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1
Gavloski, J. E., U. Ekuere, A. Keddie, L. Dosdall, L. Kott, and A. G. Good. "Identification and evaluation of flea beetle (Phyllotreta cruciferae) resistance within Brassicaceae." Canadian Journal of Plant Science 80, no. 4 (October 1, 2000): 881–87. http://dx.doi.org/10.4141/p99-164.
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All currently registered varieties of canola/oilseed rape, Brassica napus and B. rapa, are susceptible to attack by flea beetles, although to varying degrees. The development of resistant cultivars would be an environmentally acceptable means to reduce the damage caused by flea beetles. Seedlings from 10 species of Brassicaceae were evaluated for levels of antixenosis resistance to flea beetles in the laboratory, along with 308 Sinapis alba/B. napus hybrids. Thlaspi arvense and 11 cultivars of S. alba were resistant to feeding by flea beetles. In addition, 34 S. alba/B. napus hybrids were resistant to feeding by flea beetle in at least one test, although many of these failed to demonstrate resistance with repeated testing. One hybrid line was resistant to feeding by flea beetles each of the four times it was tested, while another was resistant in three out of four tests. These data indicate that resistance to flea beetles within the Brassicaceae is a genetic trait and can be transferred by interspecific hybridization. This information is the first step towards introgression of genetic sources of flea beetle resistance from resistant relatives into canola varieties. Key words: Flea beetles, Phyllotreta cruciferae, Brassica, resistance, antixenosis, introgression
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Augustin, Arja, Unto Tulisalo, and Seppo Korpela. "Flea beetles (Coleoptera, Chrysomelidae, Halticinae) on rapeseed and sugarbeet in Finland." Agricultural and Food Science 58, no. 2 (April 1, 1986): 69–82. http://dx.doi.org/10.23986/afsci.72222.
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Surveys of the incidence of flea beetles on sugarbeet and rapeseed were carried out in eight localities in southern and central Finland in 1972 and 1980—83. The first flea beetles emerged from overwintering in late April to early May, depending on the temperature. The majority, however, appeared during the second half of May, when daily temperatures occasionally reached +20°C. Flea beetles found their host plants by olfactory orientation. Two population peaks occurred during the growing season. The overwintered flea beetles formed the first peak in late May to early June and the adults of the new generation the second peak starting in late July. The incidence of flea beetles fluctuated greatly on the cultivation, as the flea beetles moved only short distances and showed thus very local occurrence. The availability of host plants greatly affected their reproduction rate, and thus the annual and regional differences in the incidence of the flea beetles were great and depended solely on the availability of host plants. Therefore it was difficult to establish any countrywide differences in the incidence of the beetles. Only Phyllotreta undulata (Kutsch.) and P. striolata (F.) were of any importance aspests of rapeseed. P. undulata made up some 80—90 % and P. striolata some 10 % of the total number of flea beetles on rapeseed. P. striolata was more abundant on radish than on rapeseed. Sugarbeet was damaged only by Chaetocnema concinna (Marsh). Other species of flea beetles were also observed in small numbers on rapeseed, radish and sugarbeet. They did not, however, cause any damage, but spread from adjacent cultivated plant species or weeds. The suction trap collected only a few flea beetles, but clearly revealed their activity periods. Damage caused by flea beetles is most harmful during the short seedling stage. At that time one flea beetle per plant was considered the threshold level for control measures. Later, even several flea beetles did not significantly hamper the growth. Seed coating efficiently prevented damage by flea beetles. The general incidence of flea beetles observed during this study was so low that coating of the seed was not justified. Chemical control of blossom beetle efficiently reduced flea beetles as well. The abandoning of the cultivation of winter rape also reduced the total number of flea beetles.
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LAMB, R. J. "ASSESSING THE SUSCEPTIBILITY OF CRUCIFER SEEDLINGS TO FLEA BEETLE (Phyllotreta spp.) DAMAGE." Canadian Journal of Plant Science 68, no. 1 (January 1, 1988): 85–93. http://dx.doi.org/10.4141/cjps88-009.
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A 5-yr field study to develop a method for assessing the susceptibility of crucifer seedlings to damage by the flea beetles Phyllotreta cruciferae (Goeze) and Phyllotreta striolata (F.) is described. The recommended method consisted of five replicate 5-m rows per cultivar in a randomized complete-block design. Each test was sown three times at weekly intervals, to assure that at least one test received an appropriate level of flea beetle damage. Each test was assessed 4–5 wk after seeding by counting the number of surviving seedlings in each row and by weighing the dried aboveground portion of 10 randomly selected seedlings, although the latter discriminated fewer lines. The damage caused by flea beetles varied spatially, but this source of variation was minor and did not compromise the tests. This method proved adequate for discriminating among crucifer species and agronomically similar cultivars, some of which showed consistent, significant differences in their responses to flea beettle damage.Key words: Crucifer, rapeseed, flea beetle, pest resistance
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Pernal, S. F., D. G. Senanayake, and N. J. Holliday. "PATTERNS OF FEEDING INJURY TO POTATO BY THE POTATO FLEA BEETLE (COLEOPTERA: CHRYSOMELIDAE) IN MANITOBA." Canadian Entomologist 128, no. 5 (October 1996): 791–804. http://dx.doi.org/10.4039/ent128791-5.
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AbstractThe amount and distribution of foliar feeding injury by adult potato flea beetles, Epitrix cucumeris (Harris), were examined on individually caged potato plants grown in field plots in Manitoba. Plants were either maintained as uninfested controls, or were exposed throughout the growing season to different insect densities that mimicked the natural seasonal pattern of infestation. In 1984, a trial was conducted using cv. ‘Norland’ exposed to four different densities of potato flea beetles. In 1989 and 1990, cv. ‘Russet Burbank’ was exposed to potato flea beetles, and in some treatments, plants were exposed to early summer infestations of Colorado potato beetles, Leptinotarsa decemlineata (Say). In each trial, during the late summer period of high potato flea beetle density, the amount and distribution of flea beetle feeding injury were assessed at weekly intervals. Counts of feeding punctures in single leaflets were made from leaves in the upper, middle, and lower third of each caged plant, and these data were subjected to repeated measures analysis of variance. In each of the 3 years, increasing the number of flea beetles increased the mean number of feeding punctures per leaflet in an approximately linear fashion; however, the number of punctures per beetle varied between cultivars and years. In 1984 and 1990, the number of feeding punctures per leaflet was least in the upper third of the plants, and greater in the lower, or middle and lower, third of plants. However, in 1989, the vertical distribution of feeding punctures was relatively even. Previous feeding by Colorado potato beetles increased the mean number of flea beetle feeding punctures per leaflet and changed the vertical distribution of feeding punctures. Rainfall and temperature were correlated with patterns of flea beetle injury; injury was concentrated on lower leaflets during weeks of greater rainfall, and upper leaflets were injured most during weeks with higher average temperatures. It is concluded that flea beetles exhibit preferences for feeding in specific portions of potato plants, and that these preferences change in response to previous defoliation and are influenced by meteorological conditions. Consequently, counting feeding punctures would not be a reliable method of assessing whether control measures for potato flea beetles are justified.
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Dillard, H. R., A. C. Cobb, and J. S. Lamboy. "Transmission of Alternaria brassicicola to Cabbage by Flea Beetles (Phyllotreta cruciferae)." Plant Disease 82, no. 2 (February 1998): 153–57. http://dx.doi.org/10.1094/pdis.1998.82.2.153.
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In 1995 and 1996, flea beetles (Phyllotreta cruciferae) were observed in the field feeding on cabbage plants that were infected with Alternaria brassicicola. Flea beetles were captured in glass vials, etherized, and placed on agar media for isolation of A. brassicicola. In 1995, A. brassicicola was isolated from 13 out of 69 (18.8%) flea beetles in the first test and 38 out of 132 (28.8%) in the second test. In 1996, flea beetles were collected nine times during the growing season, and the isolation frequency increased from 0 to 77% as the crop approached maturity. In another study, flea beetles were collected from a field of A. brassicicola-infected cabbage, enclosed in plastic bags containing potted healthy cabbage plants, and then placed on a shaded greenhouse bench for 6 days. Alternaria leaf spot developed on plants that were infested with the contaminated flea beetles. Feces obtained from flea beetles that fed on cabbage infected with A. brassicicola contained intact and broken conidia of A. brassicicola and undigested pieces of cabbage leaf. The conidia were viable after passing through the flea beetles, as evidenced by their germination on the glass slides used for collecting the feces. Conidia of A. brassicicola were observed by scanning electron microscopy on all parts of flea beetle bodies, including wings, mouthparts, antennae, and legs.
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Esker, P. D., and F. W. Nutter. "Temporal Dynamics of Corn Flea Beetle Populations Infested with Pantoea stewartii, Causal Agent of Stewart's Disease of Corn." Phytopathology® 93, no. 2 (February 2003): 210–18. http://dx.doi.org/10.1094/phyto.2003.93.2.210.
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In order to better understand the epidemiology of the Stewart's disease of corn pathosystem, quantitative information concerning the temporal dynamics of the amount of pathogen inoculum present in the form of Pantoea stewartii-infested corn flea beetles (Chaetocnema pulicaria) is needed. Temporal changes in the proportion of P. stewartii-infested corn flea beetle populations were monitored by testing individual corn flea beetles for the presence of P. stewartii using a peroxidase-labeled, enzyme-linked immunosorbent assay. Approximately 90 corn flea beetles were collected each week from seven locations in Iowa from September 1998 through October 2000 using sweep nets. The proportion of P. stewartii-infested beetles at the end of the 1998 growing season ranged from 0.04 to 0.19. In spring 1999, the proportion of overwintering adult corn flea beetles infested with P. stewartii ranged from 0.10 to 0.11 and did not differ significantly from the previous fall based on χ2. During the 1999 corn-growing season, the proportion of infested corn flea beetles ranged from 0.04 to 0.86, with the highest proportions occurring in August. In fall 1999, the proportion of beetles infested with P. stewartii ranged from 0.20 to 0.77. In spring 2000, the proportion of overwintering adult corn flea beetles infested with P. stewartii ranged from 0.08 to 0.30; these proportions were significantly lower than the proportions observed in fall 1999 at Ames, Chariton, and Nashua. During the 2000 corn-growing season, the proportion of P. stewartii-infested corn flea beetles ranged from 0.08 to 0.53, and the highest observed proportions again occurred in August. Corn flea beetle populations sampled in late fall 2000 had proportions of infested beetles ranging from 0.08 to 0.20. This is the first study to quantify the temporal population dynamics of P. stewartii-infested C. pulicaria populations in hybrid corn and provides new quantitative information that should be useful in developing risk models to predict the seasonal and site-specific risks associated with Stewart's disease of corn.
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Hallett, Rebecca H., Heather Ray, Jennifer Holowachuk, Juliana J. Soroka, and Margaret Y. Gruber. "Bioassay for assessing resistance of Arabidopsis thaliana L. (Heynh.) to the adult crucifer flea beetle, Phyllotreta cruciferae (Goeze) (Coleoptera: Chrysomelidae)." Canadian Journal of Plant Science 85, no. 1 (January 1, 2005): 225–35. http://dx.doi.org/10.4141/p03-122.
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A bioassay arena and a laboratory screening protocol were developed for assessing lines of Arabidopsis thaliana L. (Heynh.) for feeding damage by the adult crucifer flea beetle, Phyllotreta cruciferae (Goeze). The arena consists of a 96-well microtitre plate with a modified top to contain flea beetles and allow ventilation. Eight lines of A. thaliana, arranged in an 8 × 8 Latin square design, were screened simultaneously in each arena using 50 starved flea beetles. Two cotyledons and the first pair of true leaves per plant were rated visually under a dissecting microscope using a visual damage rating scale. The protocol was used to screen 29 wild ecotypes, eight mutant lines and a single transgenic line of A. thaliana. Discrimination between both cotyledon and leaf tissue was apparent for young beetles that were both non-reproductive or reproductive, but not for old reproductive beetles. Differences were observed between Asian and European ecotypes of A. thaliana, suggesting that geographic origin may play a role in susceptibility of Arabidopsis ecotypes to flea beetle feeding. The transparent testa regulatory gene mutants (lines 82, 111, 164) were most susceptible to flea beetle feeding, possibly indicating a role for anthocyanins and/or flavonoids in governing flea beetle susceptibility. Significant variation in damage levels indicates that expression of flea beetle resistance in the A rabidopsis genome is plastic, and that potential exists to use the wide array of publicly available Arabidopsis germplasm as tools in the transfer of resistance to agronomically important host plants. Key words: Seedling bioassay, Arabidopsis thaliana, wild ecotypes and mutants, crucifer flea beetle, Phyllotreta cruciferae, host plant resistance
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Nagalingam, Tharshinidevy, and Alejandro C. Costamagna. "Two methods for rearing the striped flea beetle Phyllotreta striolata (Coleoptera: Chrysomelidae) under laboratory conditions." Canadian Entomologist 151, no. 5 (July 26, 2019): 677–83. http://dx.doi.org/10.4039/tce.2019.44.
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AbstractThe striped flea beetle, Phyllotreta striolata (Fabricius) (Coleoptera: Chrysomelidae), is a major pest of canola (Brassica Linnaeus, Brassicaceae) on the Canadian prairies. The previously published methods to rear striped flea beetles under laboratory conditions are not sufficient to maintain laboratory colonies over a sustained period of time. Here, we describe two methods to rear striped flea beetles in the laboratory. The first method produces both immature stages and adult flea beetles using Napa cabbage (Brassica napa subsp. pekinensis (Loureiro) Hanelt) and canola as food sources. Beetles reared using this method produced an average of 9.7 ± 4.5 eggs, had a juvenile development period of between 26 and 33 days, and had an adult longevity between 17 and 55 days. Between 62% and 90% of the colony-reared eggs resulted in the successful development to an adult beetle. The second method uses canola as the only host, and facilitates easy access to high quantities of adult beetles. This method resulted in a six-fold to nine-fold increase in adult numbers per generation. Developmental time from adult to adult ranged from 25 to 30 days. Our two methods facilitated rearing striped flea beetles for several generations in the laboratory with or without hibernation.
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Michael, Saluta, Joan A. Lasota, and James E. Roberts. "Yield Response and Efficacy of Penncap-M on Chinese Cabbage, 1984." Insecticide and Acaricide Tests 10, no. 1 (January 1, 1985): 84–85. http://dx.doi.org/10.1093/iat/10.1.84a.
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Abstract A randomized complete block design replicated 4 times was used. Plots were 7.5 ft by 3 ft and consisted of 10 plants per replicate. There was a 3-ft row spacing, 1.5 ft between plants and a 3-ft alley spacing between replicates. Prior to planting, 3 lb 10-10-10- fertilizer/100 sq ft and 10 lb lime/100 sq ft were incorporated into a tilled plot. The soil was fumigated with bromomethane (1 lb/100 sq ft). Seedlings were transplanted on 31 Jul. Insecticide was applied as a foliar broadcast spray over the row using a compressed air sprayer. A Teejet 8003 Fan type nozzle (25-30 psi, 20 gal/acre) was used for the first application, and 2 Teejet 8003 nozzles, with a boom spacing of 30 inches, were used for the second and third applications. Applications, which were made on 8 Aug, 15 Aug and 5 Sept, corresponded with the seedling, post-seedling and mature plant growth stages, respectively. Prior to these experimental treatments, an application of methomyl was delivered to all plants on 2 Aug. This was necessary to reduce a heavy flea beetle infestation which would have resulted in heavy seedling mortality if left untreated (Penncap-M was not vet available for use). The presence of flea beetle adults and their damage was assessed on 15 Aug. The following rating index was used to assess the quantity of adult flea beetles per plant; (0 = ((beetles, 1 = 1- 10 beetles, 2 = 11 - 20 beetles, 3 = 21 - 30 beetles, 4 = 31 - 40 beetles, 5 = 41-50 beetles, 6 = 50+ beetles). The number of flea beetle feeding scars in a 1 cm2 area at the center of 1 randomly chosen leaf per plant was used for rating flea beetle feeding damage. Yield data were collected on 20 Sep by weighing marketable heads.
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Ruan, Yongying, Alexander S. Konstantinov, Guanya Shi, Yi Tao, You Li, Andrew J. Johnson, Xiaozhu Luo, et al. "The jumping mechanism of flea beetles (Coleoptera, Chrysomelidae, Alticini), its application to bionics and preliminary design for a robotic jumping leg." ZooKeys 915 (February 24, 2020): 87–105. http://dx.doi.org/10.3897/zookeys.915.38348.
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Flea beetles (Coleoptera, Chrysomelidae, Galerucinae, Alticini) are a hyperdiverse group of organisms with approximately 9900 species worldwide. In addition to walking as most insects do, nearly all the species of flea beetles have an ability to jump and this ability is commonly understood as one of the key adaptations responsible for its diversity. Our investigation of flea beetle jumping is based on high-speed filming, micro-CT scans and 3D reconstructions, and provides a mechanical description of the jump. We reveal that the flea beetle jumping mechanism is a catapult in nature and is enabled by a small structure in the hind femur called an ‘elastic plate’ which powers the explosive jump and protects other structures from potential injury. The explosive catapult jump of flea beetles involves a unique ‘high-efficiency mechanism’ and ‘positive feedback mechanism’. As this catapult mechanism could inspire the design of bionic jumping limbs, we provide a preliminary design for a robotic jumping leg, which could be a resource for the bionics industry.
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Milbrath, Lindsey R., Michael J. Weiss, and Blaine G. Schatz. "INFLUENCE OF TILLAGE SYSTEM, PLANTING DATE, AND OILSEED CRUCIFERS ON FLEA BEETLE POPULATIONS (COLEOPTERA: CHRYSOMELIDAE)." Canadian Entomologist 127, no. 3 (June 1995): 289–93. http://dx.doi.org/10.4039/ent127289-3.
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AbstractCultural practices (tillage, planting date) were examined for their effect on flea beetle, Phyllotreta cruciferae (Goeze), populations in three species of oilseed crucifers—Brassica napus L., B. rapa L., and Crambe abyssinica Hochst. No-till appeared to reduce flea beetle densities when compared with conventional tillage. The greater structural diversity of the no-till plots might be interfering with host plant location. Earlier plantings had significantly more flea beetles per plant than later plantings. The Brassica crops yielded higher densities of beetles compared with crambe, supporting earlier reports of crambe resistance.
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Palaniswamy, P., and R. P. Bodnaryk. "A WILD BRASSICA FROM SICILY PROVIDES TRICHOME-BASED RESISTANCE AGAINST FLEA BEETLES, PHYLLOTRETA CRUCIFERAE (GOEZE) (COLEOPTERA: CHRYSOMELIDAE)." Canadian Entomologist 126, no. 5 (October 1994): 1119–30. http://dx.doi.org/10.4039/ent1261119-5.
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AbstractThe leaf trichome densities of upper and lower surfaces of wild, Mediterranean Brassica spp. were determined using light and electron microscopic techniques. Two groups of plant species, one with a density of 2171–5312 trichomes per cm2 and the other with 0–30 trichomes per cm2, were tested in the laboratory for resistance against flea beetle feeding. The extent of feeding was determined in choice tests using leaf discs or detached whole leaves and in no-choice tests using clip-on cages on intact plants. Of the seven species tested, only two, B. villosa Biv. and B. villosa Biv. subsp. drepanensis which had a trichome density of > 2172 per cm2, were found to be highly resistant to flea beetle feeding. All other species had a trichome density of < 30 per cm2 and all suffered significant damage from flea beetle feeding. Behavioural observations indicated that a high density of trichomes on undamaged B. villosa leaves acted as a physical barrier to flea beetle feeding by preventing the flea beetles from firmly settling on the leaf surface to initiate feeding. Flea beetles readily initiated feeding on areas of B. villosa leaves where trichomes were inadvertently damaged suggesting that this plant did not contain significant concentrations of feeding deterrents. Electroantennogram (EAG) studies also indicated that B. villosa leaves are as stimulating to flea beetles as other Brassica species tested. Behavioural observations, feeding tests, and EAG studies indicated that trichomes, not other factors such as chemical repellents or feeding deterrents, are responsible for the resistance in B. villosa plants to flea beetle feeding.
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Soroka, Juliana J., and Larry F. Grenkow. "When is fall feeding by flea beetles (Phyllotreta spp., Coleoptera: Chrysomelidae) on canola (Brassica napus L.) a problem?" Canadian Journal of Plant Science 92, no. 1 (January 2012): 97–107. http://dx.doi.org/10.4141/cjps2011-088.
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Soroka, J. J. and L. F. Grenkow. 2012. When is fall feeding by flea beetles ( Phyllotreta spp., Coleoptera: Chrysomelidae) on canola ( Brassica napus L.) a problem? Can. J. Plant Sci. 92: 97–107. Two cultivars of Brassica napus canola were seeded in mid-May and early June in three field experiments in each of 3 yr near Saskatoon, Saskatchewan, to determine the effects of late-season flea beetle feeding on seed yields. In the first experiment, canola was sprayed with insecticide late in the summer to eliminate naturally-infesting flea beetles. In the second, 1×1×1.5 m screen cages were placed over early- and late-seeded canola at flowering and infested with flea beetles as canola matured. In the third investigation, sleeve cages were placed over individual plants and infested with 100 flea beetles. Flea beetles had no detrimental effects on early-seeded canola in any experiment, but did affect seed yields of late-seeded plots in some trials. Over two cultivars in 1 year, late-seeded plants in cube cages infested with about 350 flea beetles per plant when lower pods were turning from translucent to green in colour reduced yield by 241 kg ha−1 over control yields. Seed weights in these late-seeded plots were decreased from 2.68 g per 1000 seeds in uninfested cages to 2.44 g per 1000 seeds in infested cages. Populations of 100 flea beetles per plant in sleeve cages had no effect on harvest parameters in any seeding date or year.
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Senanayake, D. G., and N. J. Holliday. "SEASONAL ABUNDANCE OF FOLIAGE-DWELLING INSECT PESTS IN COMMERCIAL FIELDS AND INSECTICIDE-FREE PLOTS OF POTATO IN MANITOBA." Canadian Entomologist 121, no. 3 (March 1989): 253–65. http://dx.doi.org/10.4039/ent121253-3.
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AbstractPatterns of seasonal abundance of Colorado potato beetle, Leptinotarsa decemlineata (Say), potato flea beetle, Epitrix cucumeris (Harris), potato leafhopper, Empoasca fabae (Harris), and aphids on potato cv. Norland are reported for the 1983–1985 growing seasons in southern Manitoba. Each year, Colorado potato beetles and potato flea beetles underwent one generation on the crop. There were two peaks of leafhopper abundance in 1983 and 1984, but only one was evident in 1985. Aphid populations rose to a single peak in August of each year.In experimental plots in the absence of insecticides, Colorado potato beetles completely defoliated plants in two seasons out of the three. In commercial fields, insecticide sprays applied in July and early August greatly reduced populations of Colorado potato beetles for the rest of the season, and there was no defoliation at harvest. Insecticides had less effect on potato flea beetle populations. Leafhopper and aphid populations were small at the time of spraying.
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Twardowski, Jacek, Michał Hurej, Radosław Ścibior, and Andrzej Kotecki. "The effect of different seeding densities of linseed (Linum usitatissimum L.) on flax flea beetles (Coleoptera: Chrysomelidae)." Journal of Plant Protection Research 57, no. 2 (June 1, 2017): 158–66. http://dx.doi.org/10.1515/jppr-2017-0022.
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AbstractLinseed, one of the oldest cultivated crops, is again gaining in importance, mainly due to its nutritional benefits and biomedical applications. Therefore, it is expected that herbivores will also exist in greater abundance. Among them the flea beetle,Aphthona euphorbiaeSchrank andLongitarsus parvulusPaykull are considered to be serious pests of flax grown for fibre and seeds in Europe. The aim of this study was to determine flax flea beetles’ abundance, species richness and seasonal dynamics on linseed grown at different densities. It was expected that linseed seeding density can significantly affect flea beetle populations. The experiment was carried out in Lower Silesia, Poland, from 2011 to 2013. A genetically modified type of linseed overproducing flavonoids was used. Flea beetles and the damages they caused were determined on plants and also a sweep net was used for the collection of adult beetles. During the three years of the study 15 species of flea beetles were identified from oil flax plants, withA. euphorbiaeandL. parvulusbeing dominant. In terms of the total catch, the tendency was for beetle numbers to decrease with increasing plant density. Flax flea beetles feeding on linseed plants, irrespective of plant density, had two peaks of abundance. The first peak was lower and occurred in June, when plants were at the blooming stage. This peak was caused by overwintering adults who colonized crops in spring. The second, higher peak of abundance was recorded in the second half of July, when plants were at the ripening stage. This peak was formed by adults of the new generation. Each year, at the higher population peak of abundance, the flea beetles were most numerous on plants grown at the lowest density. There was one period, lasting either from mid-May to the first few days of June, or from the beginning of June to mid-June, during which the number of holes and damage on plants of each treatment were highest. During the three years of the study there were several cases of significantly higher numbers of flea beetle feeding symptoms on plants grown at the lowest density as compared to the medium and highest densities.
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Ekbom, Barbara, Anna-Karin Kuusk, Gerard Malsher, Sandra Åström, and Anna Cassel-Lundhagen. "Consumption of flea beetles (Phyllotreta, Coleoptera: Chrysomelidae) by spiders in field habitats detected by molecular analysis." Canadian Entomologist 146, no. 6 (April 24, 2014): 639–51. http://dx.doi.org/10.4039/tce.2014.14.
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AbstractFlea beetles, Phyllotreta Chevrolat (Coleoptera: Chrysomelidae) species, are often found in oilseed rape (OSR), Brassica napus Linnaeus (Brassicaceae). Among predators in the generalist predator complex present in agricultural fields, wolf spiders (Araneae: Lycosidae) are found on the ground and cobweb spiders (Araneae: Theridiidae) build webs in the foliage. We present group-specific primers developed for five flea beetle species within the genus Phyllotreta and study the incidence of predation of flea beetles by these spider groups using DNA-based gut-content analysis. Wolf spiders of the genus Pardosa Koch and the cobweb spider, Phylloneta impressa (Koch), were collected in three winter OSR fields. Flea beetle densities as well as the occurrence of predators and alternative prey were monitored. In total 19.4% of the collected Pardosa tested positive for flea beetle DNA in the polymerase chain reaction analyses, whereas 10% P. impressa were positive. Pardosa were more likely to be positive for flea beetle DNA when Pardosa activity density was low. Phylloneta impressa were more likely to be positive for flea beetle DNA if they were positive for pollen beetle DNA. Implications of these results for conservation biological control and future studies of food webs in OSR are discussed.
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Menelas, B., C. C. Block, P. D. Esker, and F. W. Nutter. "Quantifying the Feeding Periods Required by Corn Flea Beetles to Acquire and Transmit Pantoea stewartii." Plant Disease 90, no. 3 (March 2006): 319–24. http://dx.doi.org/10.1094/pd-90-0319.
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The feeding periods required by corn flea beetles to acquire and transmit Pantoea stewartii were investigated in the Stewart's disease of corn pathosystem. To quantify the effect of acquisition feeding period on percentage of acquisition, field-collected corn beetles were allowed to feed for 6, 12, 24 36, 48, and 72 h on corn seedlings previously inoculated with a rifampicin- and nalidixic acid-restraint strain of P. stewartii. Acquisition of P. stewartii by corn flea beetles was considered positive if the rifampicin- and nalidixic acid-marked strain was recovered on selective media. To quantity the effect of transmission feeding period on percent transmission of P. stewartii by corn flea beetles, P. stewartii- infested corn flea beetles were allowed to feed on healthy corn seedlings for periods of 3, 6, 12, 24, 36, 48, and 72 h. After the appropriate transmission feeding period, leaf tissues surrounding the sites of feeding scars were cultured for the presence of the P. stewartii-marked strain. Transmission of P. stewartii was considered positive if the marked strain was recovered on selective media. Acquisition of P. stewartii occurred within 6 h and the percentage of corn flea beetles that had acquired P. stewartii after 72 h ranged from 68 to 94%. The change in P. stewartii acquisition by corn flea beetles (Y) with respect to acquisition feeding period (X) was best described by the Gompertz model, with R2 values ranging from 91 to 99%. The mean time for acquisition by 50% of the corn flea beetles was 36.5 ± 11.6 h. The minimum transmission feeding time required for corn flea beetles to transmit P. stewartii following a 48-h acquisition feeding period was less than 3 h. The percent transmission of P. stewartii by corn flea beetles was nearly 100% after a 48-h transmission feeding period and was 100% by 72 h. Among population growth models evaluated, the monomolecular model best described the relationship between percent transmission (Y) and transmission feeding periods (X), with R 2 values of up to 84%. However, a nonlinear form of the monomolecular model better quantified the relationship between percent transmission and transmission feeding period, because pseudo-R2 values ranged between 98.1 and 99.5%. The predicted transmission feeding time required for 50% of P. stewartii-infested corn flea beetles to transmit the pathogen was 7.6 ± 0.87 h. These results suggest that the corn flea beetle is a highly efficient vector that can quickly acquire and transmit P. stewartii, thereby requiring insecticide seed treatments and foliar insecticides that act quickly to prevent corn flea beetles from acquiring and transmitting P. stewartii to corn plants.
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Brockman, Robert, Ryan Kuesel, Kendall Archer, Kyla O'Hearn, Neil Wilson, Delia Scott, Mark Williams, Ricardo Bessin, and David Gonthier. "The Impact of Plant Essential Oils and Fine Mesh Row Covers on Flea Beetle (Chrysomelidae) Management in Brassicaceous Greens Production." Insects 11, no. 10 (October 19, 2020): 714. http://dx.doi.org/10.3390/insects11100714.
Full textAbstract:
Brassicaceous leafy greens are an important crop for small growers but are difficult to produce due to damage by flea beetles. Flea beetles are problematic for growers as they chew many small holes through leaves rendering produce unmarketable. We tested the efficacy of several essential oils, the woven-mesh row cover ProtekNet, and the spunbonded row cover Agribon, compared to organic and conventional insecticides and no spray controls in the spring and fall of 2019. We found that the two row cover treatments (Agribon and ProtekNet) provided the best control of flea beetles and associated damage. Thyme oil was highly phytotoxic and killed the crop entirely and rosemary and neem essential oils caused mild phytotoxic burns. Organic insecticides rarely performed better than the no spray control. While conventional insecticides controlled most flea beetles, the crop was often still too highly damaged to sell. The results of our study suggest row covers offer producers an effective method of flea beetle control that reduces their dependence on insecticides for conventional and organic production.
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Mason, James, Adam Michael Alford, and Thomas Patrick Kuhar. "Flea Beetle (Coleoptera: Chrysomelidae) Populations, Effects of Feeding Injury, and Efficacy of Insecticide Treatments on Eggplant and Cabbage in Southwest Virginia." Journal of Economic Entomology 113, no. 2 (December 27, 2019): 887–95. http://dx.doi.org/10.1093/jee/toz355.
Full textAbstract:
Abstract Flea beetles, are common pests of cabbage Brassica oleracea L. (Brassicales: Brassicaceae) and eggplant Solanum melongena L. (Solanales: Solanaceae), but little is known about the flea beetle populations in Virginia, their impact on yield, or the most effective control methods. This research investigates flea beetle populations and the impact of their feeding injury on cabbage and eggplant in Southwest Virginia and determines the most efficacious control methods. In Whitethorne, VA, cabbage and eggplant crops were vacuum sampled weekly throughout two summers (2015, 2016). Crucifer flea beetle, Phyllotreta cruciferae (Goeze) (Coleoptera: Chrysomelidae), and striped flea beetle, Phyllotreta striolata Fabr. (Coleoptera: Chrysomelidae) were found on cabbage; whereas, eggplant flea beetle, Epitrix fucula (Crotch) (Coleoptera: Chrysomelidae), and the tobacco flea beetle, Epitrix hirtipennis (Melsheimer) (Coleoptera: Chrysomelidae) were found on eggplant. To evaluate the impact of flea beetle feeding on these plants flea beetle densities and defoliation were assessed weekly and individual plant, as well as whole plot yields, assessed at harvest. For cabbage, significant yield reductions were observed between 1 and 20% and >60% defoliation. Similarly, significant yield reductions were observed between 41 and 60% and >60% defoliation for eggplant. The efficacy of various insecticides was also evaluated. Soil application of the systemic neonicotinoid dinotefuran, imidacloprid, and the foliar-applied bifenthrin resulted in the fewest beetles, the least amount of leaf defoliation, and the highest yield in cabbage and eggplant. This research helps vegetable growers to better understand the severity of these pests and how to effectively combat them.
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Pachagounder, Palaniswamy, and Robert J. Lamb. "FEEDING PREFERENCES OF A FLEA BEETLE, PHYLLOTRETA CRUCIFERAE (COLEOPTERA: CHRYSOMELIDAE), AMONG WILD CRUCIFERS." Canadian Entomologist 130, no. 2 (April 1998): 241–42. http://dx.doi.org/10.4039/ent130241-2.
Full textAbstract:
The crucifer flea beetle, Phyllotreta cruciferae (Goeze), feeds primarily on plants in the Brassicaceae (Cruciferae) (Feeny et al. 1970). Introduced from Europe, it is now a widespread pest of canola, Brassica napus L. and Brassica rapa L., in North America (Lamb and Turnock 1982; Weiss et al. 1991). Before canola occupied so much crop land in western Canada, flea beetles were present and presumably fed mostly on wild crucifers. These native and weedy crucifers are potential sources of resistance genes that might be transferred to canola. We examine feeding preferences of flea beetles among nine wild crucifers (Table 1) to determine which, if any, are avoided. The suitability of these plants has already been examined for another crucifer-feeding chrysomelid, the red turnip beetle, Entomoscelis americana Brown (Gerber and Obadofin 1981; Gerber 1984), and the feeding responses of the beetles are compared.
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Burgess, L., and C. F. Hinks. "PREDATION ON ADULTS OF THE CRUCIFER FLEA BEETLE, PHYLLOTRETA CRUCIFERAE (GOEZE), BY THE NORTHERN FALL FIELD CRICKET, GRYLLUS PENNSYLVANICUS BURMEISTER (ORTHOPTERA: GRYLLIDAE)." Canadian Entomologist 119, no. 5 (May 1987): 495–96. http://dx.doi.org/10.4039/ent119495-5.
Full textAbstract:
Predation on adults of the crucifer flea beetle, Phyllotreta cruciferae (Goeze), by the northern fall field cricket, Gryllus pennsylvanicus Burmeister, was recorded in laboratory tests to identify predators of flea beetles that attack canola and mustard crops. In these tests, four field-collected adult crickets all ate live adult P. icruciferae, as did 15 of 16 lateinstar cricket nymphs. The tests were carried out in 60 by 20 mm disposable plastic Petri dishes, with a stoppered hole to facilitate introduction of flea beetles. A filter paper liner in the bottom of the dish gave the insects a firm footing.
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Nowatzki, Timothy M., and Michael J. Weiss. "Effects of simulated and flea beetle injury to cotyledons on growth of drought-stressed oilseed rape, Brassica napus L." Canadian Journal of Plant Science 77, no. 3 (July 1, 1997): 475–81. http://dx.doi.org/10.4141/p96-145.
Full textAbstract:
Simulated injury was compared with flea beetle injury on cotyledons of oilseed rape grown at various soil moistures to determine the effects of injury on seedling growth in the greenhouse. The cotyledons of 7-d-old seedlings were injured at 0, 25, 50, and 75% of the total area with a 0.5-mm mechanical pencil or by flea beetles. The soil moisture was maintained at the field capacity, half field capacity, and the permanent wilting point. The growth response of the seedlings was compared for simulated flea beetle injury and soil moisture 7, 14, and 21 d post-injury, and for simulated and flea beetle injury, and soil moisture 7 d post-injury. Simulated injury had the greatest effect on seedlings grown at the field capacity, at 7 d post-injury. At the reduced soil moistures, increased levels of simulated injury were necessary to cause a significant loss in growth. By 14 and 21 d post-injury, compensation to the simulated injury occurred. Simulated injury caused significantly less growth reduction across all injury levels compared with flea beetle injury. However, at injury levels above 25%, both simulated and flea beetle injury had similar trends in growth reduction. The simulated injury tested in these experiments cannot be used in place of flea beetles for resistance screening studies, but may be useful if incorporated as a preliminary tool. Key words: Phyllotreta cruciferae, canola, oilseed rape, injury, damage response
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Dively, Galen P., Terrence Patton, Lindsay Barranco, and Kelly Kulhanek. "Comparative Efficacy of Common Active Ingredients in Organic Insecticides Against Difficult to Control Insect Pests." Insects 11, no. 9 (September 8, 2020): 614. http://dx.doi.org/10.3390/insects11090614.
Full textAbstract:
There exists a lack of control efficacy information to enable decision-making about which organic insecticide product works best for a given insect pest. Here, we summarize results of 153 field trials on the control efficacy of common active ingredients in organic insecticides against 12 groups of the most difficult to control insect pests. These trials evaluated primarily the organic products Entrust (spinosad), Azera (pyrethrin and azadirachtin), PyGanic (pyrethrin) and Neemix (azadirachtin), which reduced pest infestations by an overall 73.9%, 61.7%, 48.6% and 46.1% respectively, averaged across all trials. Entrust was the most effective control option for many insect pests, particularly providing >75% control of flea beetles, Colorado potato beetle, cabbageworms and alfalfa weevil, but was relatively ineffective against true bugs and aphids. Azera provided >75% control of green peach aphid, flea beetles, Japanese beetle, Mexican bean beetle, potato leafhopper and cabbageworms. PyGanic was less effective than Entrust and Azera but still provided >75% control of green peach aphid, flea beetles and potato leafhopper. The growth inhibition effects of azadirachtin in Neemix were particularly effective against larvae of Mexican bean beetle and Colorado potato beetle but was generally less effective in trials with insect infestations consisting mainly of adult stages. Those insect pests that were particularly difficult to control included thrips, stinkbugs, cucumber beetles and fruitworms. Several caveats pertaining to the application of the results are discussed.
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SOROKA, J. J., and M. K. PRITCHARD. "EFFECTS OF FLEA BEETLE FEEDING ON TRANSPLANTED AND DIRECT-SEEDED BROCCOLI." Canadian Journal of Plant Science 67, no. 2 (April 1, 1987): 549–57. http://dx.doi.org/10.4141/cjps87-077.
Full textAbstract:
The effects of flea beetle (Coleoptera: Chrysomelidae) feeding on transplanted and direct-seeded broccoli (Brassica oleracea var. italica Pl.) were studied for 2 yr in field plots in south central Manitoba. Flea beetle populations were monitored in biweekly broccoli plantings and the plots were assessed for stand loss, plant damage and yield. Transplants of 4-, 3-, or 2-wk-old seedlings, direct-seeded plants and direct-seeded plants with carbofuran granules in furrow were compared. The earliest plantings had the greatest mortality, delayed harvest and most prolonged harvest period because of high beetle populations early in the season. Small transplants and newly emerged seedlings were the most severely defoliated by the beetles while broccoli plants beyond the 6- to 8-leaf stage suffered negligible damage. Direct-seeded plants without insecticide had the fewest and generally lowest-quality heads. Over both years direct-seeded broccoli yielded only 37% of the marketable harvest of direct-seeded, insecticide-protected broccoli. The old transplants were the most tolerant to flea beetle attack. Feeding on bud florets of the mature heads by the large summer generation of flea beetles in the second year of the study reduced marketable yields of all treatments.Key words: Flea beetle, broccoli, transplant, direct seed, carbofuran, Brassica oleracea var. italica Pl.
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Bodnaryk, R. P., and R. J. Lamb. "Influence of seed size in canola, Brassica napus L. and mustard, Sinapis alba L., on seedling resistance against flea beetles, Phyllotreta cruciferae (Goeze)." Canadian Journal of Plant Science 71, no. 2 (April 1, 1991): 397–404. http://dx.doi.org/10.4141/cjps91-055.
Full textAbstract:
Seedlings of Brassica napus L. 'Westar' or Sinapis alba L. 'Ochre' grown from seeds of various size were offered to flea beetles, Phyllotreta cruciferae (Goeze) in feeding tests for damage assessment. The proportion of cotyledon area damaged in both species was highest for seedlings grown from small seeds in choice and no-choice feeding tests. The proportion of seedlings killed by flea beetle feeding was also highest in seedlings from small seeds, an effect that was especially pronounced at high beetle densities (10/seedling) where 100% of seedlings from small seeds of B. napus were killed compared to 28.3% of seedlings from big seeds. For S. alba, at 20 beetles/seedling, 45.4% of seedlings from small seeds were killed compared to only 9.1% of seedlings from big seeds. Seedlings grown from big seeds of S. alba tolerated low levels of damage caused by flea beetle feeding or by scissors. No evidence for tolerance was obtained for seedlings from small seeds of S. alba or for seedlings from big or small seeds of B. napus. "Big seeds" appears to be a desirable trait that enhances crucifer seedling resistance to flea beetle attack and results in increased seedling survival. Key words: Brassica napus 'Westar', Sinapis alba 'Ochre', Phyllotreta cruciferae, flea beetle, seed size, resistance
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Palaniswamy, P., and R. J. Lamb. "WOUND-INDUCED ANTIXENOTIC RESISTANCE TO FLEA BEETLES, PHYLLOTRETA CRUCIFERAE (GOEZE) (COLEOPTERA: CHRYSOMELIDAE), IN CRUCIFERS." Canadian Entomologist 125, no. 5 (October 1993): 903–12. http://dx.doi.org/10.4039/ent125903-5.
Full textAbstract:
AbstractLaboratory experiments were conducted to determine the effect of wounding the cotyledons of Sinapis alba L. cv. Ochre, Brassica napus L. cv. Westar, B. rapa L. cv. Tobin, and C8711, a selection from Tobin, on subsequent feeding damage by the flea beetle, Phyllotreta cruciferae (Goeze). Cotyledons of 7-day-old seedlings were wounded either by puncturing them with needles (mechanical wounding) or by exposing them to flea beetles. One, 2, or 9 days following wounding, the wounded and unwounded seedlings were exposed to flea beetles and the feeding damage was estimated as a measure of antixenosis. Mechanical wounding of one of the cotyledons with 96 needle punctures induced a significant reduction in the damage of the unwounded cotyledons of S. alba, 1 or 2 days following wounding. True leaves of the wounded seedlings also showed consistently less damage than unwounded controls, 9 days following wounding. In S. alba, all three levels of mechanical wounding (i.e. 6, 24, or 96 punctures per cotyledon) reduced subsequent flea beetle damage to a similar extent. Wrapping a cotyledon of S. alba with a plastic film produced an effect similar to wounding it with needles. As with mechanical wounding, flea beetle wounding also reduced subsequent flea beetle damage in S. alba. Other plant species (B. napus and B. rapa) tested showed no measurable induced effects on subsequent feeding damage.
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Pachagounder, Palaniswamy, Robert J. Lamb, and Robert P. Bodnaryk. "RESISTANCE TO THE FLEA BEETLE PHYLLOTRETA CRUCIFERAE (COLEOPTERA: CHRYSOMELIDAE) IN FALSE FLAX, CAMELINA SATIVA (BRASSICACEAE)." Canadian Entomologist 130, no. 2 (April 1998): 235–40. http://dx.doi.org/10.4039/ent130235-2.
Full textAbstract:
AbstractFeeding damage by the crucifer flea beetle, Phyllotreta cruciferae (Goeze), was assessed on 51 accessions of false flax, Camelina sativa L., and compared with damage to seven other crucifer species. Three experiments were conducted on seedlings in laboratory arenas infested with field-collected beetles. Feeding damage was estimated visually at daily intervals for up to 7 days. Natural infestation of false flax and other crucifers was observed in the field. Flea beetles fed little (0–10% consumption) on cotyledons or true leaves of any of the false flax accessions, and fed more (59–100% consumption) on the other crucifers. Flea beetles were observed sitting on false flax in the field, sometimes in high numbers, but they did not feed. In the laboratory, beetles eventually fed on cotyledons and leaves and once feeding was initiated, it tended to continue. Resistance in false flax may result from the absence of cues that initiate feeding, rather than a feeding deterrent. The high level of resistance in false flax would likely be economically beneficial if this species is developed as an oilseed crop. False flax could also be useful experimentally for identifying the cues that attract flea beetles to plants and stimulate their feeding.
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Bodnaryk, R. P., and R. J. Lamb. "Mechanisms of resistance to the flea beetle, Phyllotreta cruciferae (Goeze), in mustard seedlings, Sinapis alba L." Canadian Journal of Plant Science 71, no. 1 (January 1, 1991): 13–20. http://dx.doi.org/10.4141/cjps91-002.
Full textAbstract:
Antixenosis (nonpreference) and tolerance were identified as two mechanisms of resistance in seedlings of mustard, Sinapis alba 'Ochre', that likely account for the high level of resistance that this plant shows to flea beetles, Phyllotreta cruciferae Goeze, in the field. Sinapis alba showed antixenosis in no-choice and choice feeding tests with a susceptible species, Brassica napus 'Westar'. The beetles consumed about twice as much of the B. napus foliage as compared with S. alba. The highest level of antixenosis occurred in younger seedlings, indicating that S. alba puts forth an optimum defense when it is most vulnerable to flea beetle herbivory. Seedlings of S. alba were tolerant of low levels of flea beetle feeding damage to their cotyledons and continued to grow at almost the same rate as undamaged seedlings, whereas the growth of B. napus declined continuously with the level of feeding damage. The level of tolerance shown by S. alba combined with antixenosis probably accounts for the resistance reported for this crop in the field. In comparison with S. alba, B. napus seedlings, which show no tolerance and are preferred hosts, succumb rapidly to flea beetle attack unless protected with an insecticide. Key words: Insect resistance, mechanism, flea beetle, seedling, mustard, Sinapis alba
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Vernon, Robert S., and Donald R. Thomson. "OVERWINTERING OF TUBER FLEA BEETLES, EPITRIX TUBERIS GENTNER (COLEOPTERA: CHRYSOMELIDAE), IN POTATO FIELDS." Canadian Entomologist 123, no. 1 (February 1991): 239–40. http://dx.doi.org/10.4039/ent123239-1.
Full textAbstract:
Early season infestations of adult tuber flea beetles, Epitrix tuberis Gentner, usually are concentrated at the edges of potato fields, and it generally has been assumed that they move into potato fields from the outside inward. This edge-effect suggests that tuber flea beetles overwinter outside potato fields, and other species of flea beetles have been reported to behave similarly (Wolfenbarger 1940; Dominick 1971; Burgess 1981). This may not be true of E. tuberis, however. Hoerner and Gillette (1928), in Colorado, noted that potatoinfesting flea beetles [probably E. cucurneris (Harris), E. subcrinata (Lec.), or E. tuberis] often congregated under piles of old potato vines in potato fields, and Hill and Tate (1942) observed flea beetles feeding on cull tubers in a potato field after harvest. These observations suggest, but do not confirm, that some flea beetles including E. tuberis may remain in harvested potato fields during winter.
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Roberts, James E., Michael Saluta, and Joan A. Lasota. "Yield Response and Efficacy of Penncap-M on Chinese Mustard, 1984." Insecticide and Acaricide Tests 10, no. 1 (January 1, 1985): 118. http://dx.doi.org/10.1093/iat/10.1.118.
Full textAbstract:
Abstract The experimental plot was a randomized block design, where each of 3 vegetable crops (Chinese cabbage, Chinese broccoli, and Chinese mustard) were replicated 4 times. Plot size for each commodity per replicate was 7.5 ft by 3 It and consisted of 10 plants. Rows were 3 ft apart, plants 1.5 ft apart, and there was a 3-ft alley spacing between replicates. Three lb 10-10-10 fertilizer/100 sq ft and 10 lb lime/100 sq ft were incorporated into the tilled plot prior to planting. Seedlings were transplanted on 31 Jul following soil fumigation with bromomethane (1 lb/100 sq ft on 27 Jul. Insecticide applications were made on 8, 15 Aug, and 5 Sep to seedling, post-seedling and mature plants, respectively. Teejet 8003 Fan type nozzles (1 for the first application and 2, with a 30-inch boom spacing, for the second and third applications) were used on a compressed air sprayer to deliver a foliar broadcast spray over the rows. Due to an extensive flea beetle infestation which would have resulted in heavy seedling mortality if left untreated, an application of Lannate was made to all plants on 2 Aug. (Penncap-M had not yet been secured for use). Flea beetle adults and their damage was assessed on 15 Aug. Flea beetle feeding damage was rated by counting the number of feeding scars in a 1 cm2 area at the center of 1 randomly chosen leaf per plant. The quantity of (lea beetles per plant was determined using the following rating index: 0 = 0 beetles, 1 = 1-10 beetles, 2 = 11-20 beetles, 3 = 21-30 beetles, 4 = 31-40 beetles, 5 = 41-50 beetles, 6 = 50+ beetles. Yield data were collected on 20 Sep by weighing whole plants.
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Lasota, Joan A., James E. Roberts, and Michael Saluta. "Yield Response and Efficacy of Penncap-M on Chinese Broccoli, 1984." Insecticide and Acaricide Tests 10, no. 1 (January 1, 1985): 74. http://dx.doi.org/10.1093/iat/10.1.74.
Full textAbstract:
Abstract Broccoli yield, population estimates and feeding damage of cruciferous pests were used as indicators to determine the efficacy of Penncap-M. There was a 3-ft row spacing, 1.5 ft between plants, and 3 ft alley spacing between replicates. Treatments were arranged in a randomized block design with 4 replicates. Seedlings were transplanted on 31 Jul, following incorporation of 3 lb 10-10-10 fertilizer/100 sq ft and 10 lb lime/100 sq ft into a tilled plot and fumigation with bromomethane (1 lb/100 sq ft). A compressed air sprayer, with Teejet 8003 Fan type nozzles (one for the first application and 2, with a boom spacing of 30 inches, for the second and third applications) were used to deliver a foliar broadcast spray. Applications were made on 8, 15 Aug, and 5 Sep, coinciding with the seedling, post-seedling and mature plant growth stages. On 2 Aug it was necessary to treat all plants with Lannate to reduce a flea beetle population which would have caused high seedling mortality if left uncontrolled. Yield data were collected on 20 Sep bv weighing whole plants. Adult flea beetle populations on whole plants were assessed on 15 Aug by using the following rating index: 0 = 0 beetles, 1 = 1-10 beetles, 2 = 11-20 beetles, 3 = 21-30 beetles, 4 = 31-40 beetles, 5 = 41-50 beetles, 6 = 50+ beetles. Flea beetle feeding damage was also evaluated on 8 Aug by counting the number of feeding scars in a 1 cm2 area at the center of 1 randomly chosen leaf per plant. At the time of harvest (20 Sep) all imported cabbageworm and cabbage looper larvae on 5 randomly chosen plants per replicate were counted.
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Elliott, R. H., M. C. Benjamin, and C. Gillott. "Laboratory studies of the toxicity of spinosad and deltamethrin to Phyllotreta cruciferae (Coleoptera: Chrysomelidae)." Canadian Entomologist 139, no. 4 (August 2007): 534–44. http://dx.doi.org/10.4039/n06-070.
Full textAbstract:
AbstractLaboratory experiments were conducted to evaluate the contact and oral toxicity of commercial formulations of spinosad and deltamethrin to adults of the crucifer flea beetle, Phyllotreta cruciferae (Goeze). Method of exposure had a significant effect on flea beetle mortality and feeding damage to canola seedlings. Topical treatment of flea beetles with deltamethrin or different concentrations of spinosad resulted in significantly lower mortality and higher feeding damage than exposure to treated canola cotyledons. Results indicated that spinosad was more toxic by ingestion than by topical contact. Mortality from treated cotyledons was significantly higher with 60 ppm deltamethrin than with 80 or 120 ppm spinosad after 24 h exposure but not after 120 h exposure. Delayed mortality in the spinosad treatments did not result in high feeding damage; damage after 120 h was not significantly different in the spinosad and deltamethrin treatments. Low concentrations of spinosad (40 ppm) strongly inhibited feeding activity within 24 h after exposure. Mortality from spinosad was higher after beetles were exposed to treated cotyledons for 120 h than for 24 h. Mortality from spinosad, but not deltamethrin, was significantly higher at 25 °C than at 15 °C. An ionic surfactant, polyethylenimine, increased the toxicity of 40 ppm spinosad. Our study suggests that spinosad has potential for use as an insecticide against crucifer flea beetles on canola.
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Palaniswamy, P., R. J. Lamb, and R. P. Bodnaryk. "ANTIBIOSIS OF PREFERRED AND NON-PREFERRED HOST-PLANTS FOR THE FLEA BEETLE, PHYLLOTRETA CRUCIFERAE (GOEZE) (COLEOPTERA: CHRYSOMELIDAE)." Canadian Entomologist 129, no. 1 (February 1997): 43–49. http://dx.doi.org/10.4039/ent12943-1.
Full textAbstract:
AbstractThe antibiosis of crucifers to flea beetles, Phyllotreta cruciferae (Goeze), was compared for Brassica juncea L., B. napus L., and B. rapa L. with low antixenosis, B. carinata L. and Sinapis alba L. with moderate antixenosis, and Thlaspi arvense L. with high antixenosis. Adult flea beetles collected from the field in early spring fed actively on intact or excised leaves of all plants except T. arvense. The beetles survived, and gained weight and fat on the Brassica species and S. alba, but not on intact foliage of T. arvense. No antibiosis was detected in any of the Brassica species or in S. alba. Intact foliage of T. arvense was so antixenotic that beetles probably starved rather than suffered from antibiosis. A low level of antibiosis was detected in excised foliage of T. arvense where the antixenosis was lost. These experiments show that estimates of beetle survival, dry weight, and fat content can be used in the laboratory to test small numbers of candidate plants for antibiosis. However, the level of antibiosis appears to vary less among Brassica species and related plants than does the level of antixenosis, and so the latter is a more promising type of resistance for use against flea beetles in canola.
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D’Alessandro, Paola, and Maurizio Biondi. "Ugandaltica gen. n., a tiny flea beetle from the forest canopy in Central Africa (Coleoptera, Chrysomelidae, Galerucinae, Alticini)." ZooKeys 746 (March 27, 2018): 123–36. http://dx.doi.org/10.3897/zookeys.746.23637.
Full textAbstract:
In this contribution,Ugandalticawagnerigen. n.andsp. n., collected from the canopies in the Budongo Forest, Uganda, is described. Similarities and affinities with other small-sized and convex-shaped flea beetle genera, occurring in the Afrotropical region, are discussed. Micrographs of diagnostic characters, including male and female genitalia, are supplied. Finally, some considerations on the ecology of canopy flea beetles are also reported.
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Zhang, Zhi-Qiang, and Peter B. McEvoy. "Responses of ragwort flea beetleLongitarsus jacobaeae(Coleoptera: Chrysomelidae) to signals from host plants." Bulletin of Entomological Research 85, no. 3 (September 1995): 437–44. http://dx.doi.org/10.1017/s0007485300036178.
Full textAbstract:
AbstractResponses of adult flea beetlesLongitarsus jacobaeae(Waterhouse), to signals from ragwort plants (Senecio jacobaeaLinnaeus) were studied by recording their directions of movement in a wind tunnel and their colonization of host-plants in the field. Starved beetle individuals, irrespective of gender, orientated toward upwind host-plants over a distance of 60 cm in the wind tunnel, whereas satiated beetles did not. In the absence of upwind host-plants, all beetles moved randomly in all directions, regardless of whether they were starved or satiated. Starved beetle individuals did not show directed movement towards hosts when plants were downwind in the wind tunnel, nor when in the presence of host-plants when the wind was absent. Groups of starved beetles orientated to upwind host-plants in the wind tunnel, as did individual beetles. In the field, plants over 60 cm upwind of the released beetles were found and colonized by more beetles than downwind plants, in spite of the presence of background vegetation. This confirms the result of laboratory experiments thatL. jacobaeaecan orient to upwind host-plants.
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Vernon, R. S., J. R. Mackenzie, and D. L. Bartel. "MONITORING TUBER FLEA BEETLE, EPITRIX TUBERIS GENTNER (COLEOPTERA: CHRYSOMELIDAE) ON POTATO: PARAMETERS AFFECTING THE ACCURACY OF VISUAL SAMPLING." Canadian Entomologist 122, no. 3 (June 1990): 525–35. http://dx.doi.org/10.4039/ent122525-5.
Full textAbstract:
AbstractThe accuracy of visual observations in estimating numbers of tuber flea beetles, Epitrix tuberis Gentner, on young potatoes was determined. Potential sources of observational error examined were as follows: (a) observer competence and experience; (b) time spent observing each plant; (c) time of day; (d) plant height; and (e) weather. Observational accuracy versus tuber flea beetle density on plants followed a linear relationship for both experienced and inexperienced observers. Marked differences between experienced and inexperienced observers generally were reduced after 2 h of sampling experience, but some observers were consistently less accurate at sighting beetles than others. When observing small plants, 5-s observations generally were more accurate at sighting beetles per second of observation than 2-, 8-, or 10-s observations. Under uniform weather conditions, accuracy was the same in the morning as in the afternoon. Observer accuracy was significantly reduced under the combined influences of observer fatigue and wind. The relationship of 5-s-per-plant sampling accuracy to plants between 14 and 56 cm in height was linear; however, a quadratic relationship is suspected for plants over the full range of plant heights (i.e. >1 cm). From these data, total tuber flea beetles per plant estimated by 5-s visual observations per plant would be: TFB = TFB0/EhE0n where TFB0 is the total number of flea beetles observed, n is the total number of plants sampled, Eh is a sampling accuracy constant for the mean plant height sampled, and E0 is the observer accuracy constant calculated as a proportion of the most proficient observer(s).
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Elliott, R. H., C. Franke, and G. F. W. Rakow. "Effects of seed size and seed weight on seedling establishment, vigour and tolerance of Argentine canola (Brassica napus) to flea beetles, Phyllotreta spp." Canadian Journal of Plant Science 88, no. 1 (January 1, 2008): 207–17. http://dx.doi.org/10.4141/cjps07059.
Full textAbstract:
A 3-yr study was conducted on four Brassica napus L. cultivars to determine the effects of seed size and seed weight on the performance and tolerance of canola seedlings to feeding damage by flea beetles, Phyllotreta spp. (Coleoptera: Chrysom elidae). Seed lots of a doubled haploid cultivar Cyclone, hybrid cultivar AC H102 and two open-pollinated cultivars Profit and AC Elect were sieved to obtain small, medium, large and very large seeds (1.4–1.6, 1.6–1.8, 1.8–2.0 and 2.0–2.2 mm diameter, respectively). Under controlled environmental conditions, leaf area, shoot weight and biomass of seedlings from large and very large seeds were 1.3–2.0 times greater than those of seedlings from small seeds. Under field conditions without insecticides, seedlings from small seeds of each cultivar had the highest flea beetle damage, poorest establishment, and lowest shoot weight, biomass and yield. Compared with small seeds, large seeds improved seedling establishment, shoot weight, biomass and yield by 1.1, 1.6–2.0, 3.0–3.5 and 1.5 times, respectively. Results indicated that seedlings from large seeds are more vigorous and tolerant to flea beetle damage than seedlings from medium or small seeds. Seedling vigour and tolerance was due to a higher initial shoot biomass and higher growth rate when flea beetle damage was severe. When damage exceeded 50%, large heavy seeds had the best stand establishment, best shoot growth and highest yield in each cultivar. Key words: Canola, flea beetles, seed size, seed weight, seedling vigour, tolerance
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Lundin, Ola. "Economic Injury Levels for Flea Beetles (Phyllotreta spp.; Coleoptera: Chrysomelidae) in Spring Oilseed Rape (Brassica napus; Brassicales: Brassicaceae)." Journal of Economic Entomology 113, no. 2 (December 27, 2019): 808–13. http://dx.doi.org/10.1093/jee/toz347.
Full textAbstract:
Abstract Flea beetles (Phyllotreta spp.) are major insect pests in spring oilseed rape (SOSR; Brassica napus L.). Prohibited use of three neonicotinoid insecticides in the European Union means that there are currently no insecticide seed treatment options available. Insecticide spraying remains as a control option, but there is a need to estimate the economic threshold for crop injury. As a first step to this end, economic injury levels were determined for flea beetles in SOSR. Data from 16 field experiments were used to quantify the relationship between flea beetle crop injury and SOSR yield, and additional data from paired sprayed and unsprayed plots in 12 commercial SOSR fields were used to determine the reduction in crop injury from a pyrethroid spray. There was a strong linear negative effect of flea beetle injury with 19 kg/ha yield loss per percent crop injury to seedlings and a pyrethroid spray reduced crop injury by 39%. These results gave an economic injury level of 11% defoliation of SOSR seedlings under average oilseed rape prices and insecticide use costs in 2017. This is considerably lower than previously used nominal thresholds of 25–30% injury to cotyledons. Increased yields and increasingly cheaper pyrethroids might be the reason for the lower levels of crop injury that warrant chemical control. The economic injury levels presented here can be used to construct economic thresholds that preferably should also take into account crop growth stage, crop growth rate, and anticipated flea beetle activity.
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Islam, M. R., M. R. Ali, W. R. Ahmed, M. M. Rahman, and H. Hira. "Varietal performance of cabbage on the incidence of flea beetles (Phyllotreta spp.)." ENTOMOLOGIA HELLENICA 24, no. 1 (June 1, 2017): 1. http://dx.doi.org/10.12681/eh.11540.
Full textAbstract:
A study was conducted at the Sher-e-Bangla Agricultural University, Bangladesh, during September 2007 to February 2008 to evaluate the varietal performance of cabbage on the incidence of flea beetles [Phyllotreta spp., (Coleoptera: Chrysomelidae)]. The experiment was laid out in a Randomized Complete Block Design comprising seven varieties viz. V1: BARI badhakopi-1/Provati, V2: BARI badhakopi-2/Agrodot, V3: Atlas-70, V4: Autumn queen, V5: Tropical queen, V6: T-776 and V7: Seisho YR. Among the different varieties of cabbage V5 (Tropical queen) performed as the best variety in terms of the lowest incidence of flea beetles (0.00 larvae/plant), lowest percent of leaves infestation (0.87 %) as well as plant infestation (2 %) caused by flea beetles. These findings will be valuable for the most appropriate management of flea beetles.
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Kozłowski, Marek Wojciech, and Hanna Legutowska. "The invasive flea beetle Luperomorpha xanthodera (Coleoptera: Chrysomelidae: Alticinae), potentially noxious to ornamental plants – first record in Poland." Journal of Plant Protection Research 54, no. 1 (January 1, 2014): 106–7. http://dx.doi.org/10.2478/jppr-2014-0017.
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Abstract A specimen of a flea beetle collected by plant sweeping from an experimental plot of oregano in Warsaw showed characteristics of the invasive species Luperomorpha xanthodera. This beetle, originating from Far East, appeared in Europe at the beginning of this century and seems to extend its range continuously. So far, it has been noted from England, Italy, France, The Netherlands, Germany, Austria and Hungary but not from Poland. Being polyphagous, adult flea beetles of this species may appear in numbers on flowers of various ornamental plants causing considerable damage.
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Culliney, Thomas W. "PREDATION ON ADULT PHYLLOTRETA FLEA BEETLES BY PODISUS MACULIVENTRIS (HEMIPTERA: PENTATOMIDAE) AND NABICULA AMERICOLIMBATA (HEMIPTERA: NABIDAE)." Canadian Entomologist 118, no. 7 (July 1986): 731–32. http://dx.doi.org/10.4039/ent118731-7.
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On three occasions in late August 1985, during the course of a study of the arthropod community associated with collards (Brassica oleracea var. acephala) (Cruciferae) in central New York State, two species of predaceous Heteroptera, the spined soldier bug, Podisus maculiventris (Say), and Nabicula americolimbata (Carayon), were observed feeding on adult flea beetles of the genus Phyllotreta. Evidence for predation on adult flea beetles is rare. Tahvanainen and Root (1972) and Kareiva (1985) reported practically no predation on adult Phyllotreta cruciferae (Goeze) in central New York, but scattered observations in Canada have documented occasional attacks on adult crucifer-infesting flea beetles by various insect predators (Gerber and Osgood 1975; Burgess 1977, 1980, 1982). This is the first record of predation on adult flea beetles by P. muculiventris and N. americolimbata. Burgess (1982) noted predation on adult P. cruciferae by another nabid, Nabis alternatus Parshley.
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Palaniswamy, P., F. Matheson, and R. J. Lamb. "FEEDING PREFERENCES OF PHYLLOTRETA CRUCIFERAE (COLEOPTERA: CHRYSOMELIDAE) FOR WILTED AND NONWILTED CRUCIFER SEEDLINGS." Canadian Entomologist 130, no. 3 (June 1998): 385–86. http://dx.doi.org/10.4039/ent130385-3.
Full textAbstract:
Water stress, especially wilting, can increase the susceptibility of plants to herbivory by insects (Holtzer et al. 1988). Insects as diverse as locusts and leaf-cutting ants prefer wilted foliage (Bernays and Lewis 1986; Vasconcelos and Cherrett 1996). Palaniswamy et al. (1997) observed that the crucifer flea beetle, Phyllotreta cruciferae (Goeze) (Coleoptera: Chrysomelidae), fed on excised and wilted foliage of Thlaspi arvense L. (Cruciferae) but not on intact and turgid foliage. If water stress can make unpalatable plants more palatable, identifying robust resistance to pests such as flea beetles will be difficult. The purpose of this study was to determine whether wilting affects feeding by the crucifer flea beetle and in particular if wilting differentially affects feeding on preferred and nonpreferred plants.
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Reed, J. T., M. R. Williams, and D. Fleming. "INTERIM RESULTS FROM THE SWEET POTATO RAMP GRANT IN MISSISSIPPI." HortScience 41, no. 3 (June 2006): 518A—518. http://dx.doi.org/10.21273/hortsci.41.3.518a.
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Results from research funded by RAMP (Risk Assessment and Mitigation Program) funds conducted with sweetpotato growers in Mississippi during 2004 and 2005 are discussed. Insects were sampled on a weekly (2004) or biweekly (2005) schedule on land planted to potatoes with and without insecticidal input. Potatoes were harvested from each cooperator's field and evaluated for insect damage one or more times at the end of the season. Insect pest populations in Mississippi sweetpotatoes were relatively low during 2004 and 2005. Under these conditions, the percentage of sweetpotatoes damaged by insects was only slightly reduced by insecticides. Chrysomelid leaf beetles including flea beetles, cucumber beetles and tortoise beetles were the most obvious group of pest insects. The most prominent insect species in sweep net samples during the season was the sweetpotato flea beetle, however damage by this pest was negligible. The most damaging insect based on our evaluation of root damage was the twelve-spotted cucumber beetle. Root feeding by whitefringed beetles, white grubs, and sugarcane beetles was sporadic within the fields in the study, and damage by these insects was generally minimal in 2004 and 2005. Preliminary assessments of the effect of crops planted the year previous to the planting of sweetpotatoes indicate the following order of greater to lesser insect damage: pasture, soybeans, corn, sweetpotato, and cotton. Delay of harvest beyond the optimum harvest date tended to increase insect damage in marketable roots. Pesticide evaluations associated with the study indicate that some reduction in damaged roots may be derived from application of a soil-incorporated insecticide at lay by.
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Elliott, R. H., L. W. Mann, and O. O. Olfert. "Effects of seed size and seed weight on seedling establishment, seedling vigour and tolerance of summer turnip rape (Brassica rapa) to flea beetles, Phyllotreta spp." Canadian Journal of Plant Science 87, no. 2 (April 1, 2007): 385–93. http://dx.doi.org/10.4141/p06-166.
Full textAbstract:
A 3-yr study was conducted on three synthetic Brassica rapa L. cultivars to determine the effects of seed size and seed weight on seedling establishment, seedling growth and susceptibility to feeding damage by flea beetles, Phyllotreta spp. (Coleoptera: Chrysomelidae). Seed lots of AC Boreal, Fairview and Hysyn 110 were sieved to obtain small, medium and large seeds (1.4–1.6, 1.6–1.8 and 1.8–2.0 mm, respectively). In the laboratory, seedlings grown from large seeds had the largest cotyledons, highest shoot dry weight and highest biomass. Shoot weights increased as seed size increased. Sized seeds of the three cultivars were grown in the field without insecticides in 1998–2000. Seedlings of small seeds had the highest flea beetle damage and poorest seedling establishment. Shoot dry weight and biomass 14–35 d after planting increased as seed size and seed weight increased. Compared with small seeds, large seeds improved shoot dry weight, biomass and seed yield by 13–43, 25–57 and 12%, respectively. Results indicated that seedlings of medium and large seeds are more vigorous and tolerant to flea beetle damage than seedlings of small seeds. Tolerance was due to a higher initial seedling weight rather than higher relative growth rate. Shoot dry weights, biomass and yield of the three cultivars were more strongly correlated with 1000-seed weight than with seed diameter. Key words: Canola, flea beetles, seed size, seedling vigour, tolerance, seed weight
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Kjer, Karl, Sung Jin Kim, and Catherine Duckett. "Comparison between molecular and morphological-based phylogenies of galerucine/alticine leaf beetles (Coleoptera: Chrysomelidae)." Insect Systematics & Evolution 34, no. 1 (2003): 53–64. http://dx.doi.org/10.1163/187631203788964890.
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AbstractPhylogenies of representative genera based on 3 molecular markers are presented. These data are combined with previously published morphological data (Lingafelter & Konstantinov 2000). The results of separate 28S-D2 rRNA, combined analysis of molecular data and molecular data combined with morphological characters for 27 genera indicate monophyly of Galerucinae s.s. and paraphyly of Flea Beetles. These results also mean that our molecular data do not support the Flea Beetles as a tribal ranking (Alticini) within the Galerucinae, nor is it's status as a separate subfamily (Alticinae) as has been proposed by other researchers. We suggest that addition of more independent characters is still needed to resolve the question of the relationships between the Flea Beetles and the galerucines.
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DAMAŠKA, ALBERT FRANTIŠEK, YONGYING RUAN, and MARTIN FIKÁČEK. "The genus Cangshanaltica (Coleoptera: Chrysomelidae: Alticinae): overview, new species, and notes on species complexes." Zootaxa 5219, no. 1 (December 7, 2022): 49–64. http://dx.doi.org/10.11646/zootaxa.5219.1.2.
Full textAbstract:
Moss-inhabiting flea beetles form a diversified ecological group of beetles with a number of recently described new species. Here, we present an overview of known species of the moss-inhabiting flea beetle genus Cangshanaltica Konstantinov, Chamorro, Prathapan, Ge & Yang, 2013 which is distributed in Eastern and South-Eastern Asia. We describe three new species: Cangshanaltica guanxiensis sp. nov. from Guanxi, China, C. marginata sp. nov. from Yunnan, China, and C. javana sp. nov., from Java, Indonesia. Additionally, we redescribe Cangshanaltica castanea (Gruev, 1985) comb. nov., a species formerly placed in Ivalia. Based on our studies of the morphological characters, we assume that some of the currently recognized species may in fact represent species complexes. Our findings also extend the known distribution of Cangshanaltica to Indonesia. A key of all described Cangshanaltica species, and an annotated checklist are provided.
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Vernon, R. S., and J. R. Mackenzie. "EVALUATION OF FOLIAR SPRAYS AGAINST THE TUBER FLEA BEETLE, EPITRIX TUBERIS GENTNER (COLEOPTERA: CHRYSOMELIDAE), ON POTATO." Canadian Entomologist 123, no. 2 (April 1991): 321–31. http://dx.doi.org/10.4039/ent123321-2.
Full textAbstract:
AbstractThe efficacies of registered and unregistered foliar sprays against the tuber flea beetle, Epitrix tuberis Gentner, were compared in 1987, 1988, and 1989 at Abbotsford, B.C. Beetles were released serially in treatment plots and visually counted after each release to determine the effectiveness and longevity of residual control. In 1989, emergence cages placed over previously treated plants measured the effect of sprays on the next generation of beetles. Pyrethroids generally resulted in beetle mortality for longer periods of time than did the nonpyrethroids carbaryl, endosulfan, chlorpyrifos, and methamidophos. Several pyrethroids provided residual beetle control for up to 7 days after application. In 1989, bifenthrin, cyfluthrin, cypermethrin, and deltamethrin were as effective in suppressing emergence of the next generation of beetles as was granular phorate applied at seeding. These studies demonstrated that foliar sprays can be a key component of E. tuberis management programs, especially those operating on soil types where the use of granular insecticides is restricted.
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Turnock, W. J., and S. A. Turnbull. "THE DEVELOPMENT OF RESISTANCE TO INSECTICIDES BY THE CRUCIFER FLEA BEETLE, PHYLLOTRETA CRUCIFERAE (GOEZE)." Canadian Entomologist 126, no. 6 (December 1994): 1369–75. http://dx.doi.org/10.4039/ent1261369-6.
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AbstractThe contact toxicities of 11 insecticides were determined with a Potter spray tower using adults of crucifer flea beetles (Coleoptera: Chrysomelidae) collected from three locations over a 3-year period. Flea beetles collected from an experimental farm at London, Ontario, where no insecticides had been used, were compared with those from canola-growing areas near Saskatoon, Saskatchewan, and Winnipeg, Manitoba. Lindane, in a seed dressing, is widely used in both Saskatchewan and Manitoba whereas carbofuran, as in-furrow granules, has been more heavily used in Manitoba than in Saskatchewan. The flea beetles from Winnipeg were significantly less susceptible to all three carbamates tested (carbofuran, carbaryl, oxamyl) than those from Saskatoon or London. Both the Winnipeg and Saskatoon flea beetles were significantly less susceptible to methamidophos than the London population but not to the other organophosphates, the organochlorine (endosulfan), or the pyrethroids that were tested. These differences may indicate resistance in the Manitoba population, but this low level would not affect the efficacy of the currently recommended insecticides. The results emphasize the need to develop control strategies that will minimize the chances that the level of resistance will increase.
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Stewart, Jeff G., Jennifer Feldman, and Debby A. LeBlanc. "RESISTANCE OF TRANSGENIC POTATOES TO ATTACK BY EPITRIX CUCUMERIS (COLEOPTERA: CHRYSOMELIDAE)." Canadian Entomologist 131, no. 4 (August 1999): 423–31. http://dx.doi.org/10.4039/ent131423-4.
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AbstractPotato plants (Solanum tuberosum, cv. Russet Burbank) genetically altered to produce the CryIIIA protein from Bacillus thuringiensis var tenebrionis were tested for susceptibility to attack by the potato flea beetle, Epitrix cucumeris (Harris), on Prince Edward Island, Canada, from 1993 to 1996. Average weekly damage to the fourth terminal leaf of transgenic potato plants was 31% lower in 1993 and 20% lower in 1994 compared with nontransgenic plants. Transgenic plants had 29% fewer potato flea beetle adults when compared with nontransgenic plants in 1994, although no difference was detected between the two plant types in 1993. Recovery of potato flea beetle pupae in the soil was noticeably lower from transgenic plants expressing the CryIIIA protein in all parts of the plant (Construct No. RBBT02-10Y1) than from either the transgenic plants that expressed the CryIIIA protein primarily in the green foliage (Construct No. RBBT04-01) or the nontransgenic plants. Adult potato flea beetles, when given a choice between transgenic and nontransgenic leaf material, fed preferentially on nontransgenic material. In contrast, when adults were not given a choice, feeding damage was similar between treatments. These results suggest that the reason for reduced feeding on transgenic potato plants by the potato flea beetle is, at least in part, due to some toxicity of the plants to immature growth stages and a preference for adults to feed on nontransgenic material when it is available.
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Bodnaryk, Robert P. "Will low-glucosinolate cultivars of the mustards Brassica juncea and Sinapis alba be vulnerable to insect pests?" Canadian Journal of Plant Science 77, no. 2 (April 1, 1997): 283–87. http://dx.doi.org/10.4141/p96-113.
Full textAbstract:
Foliar concentrations of the predominant glucosinolates in the mustards B. juncea (allyl glucosinolate, sinigrin) and S. alba (p-hydroxybenzyl glucosinolate, sinalbin) were determined in lines that had been selected in breeding programs for low levels of glucosinolates in their seeds for the oilseed market. The glucosinolate concentrations found in the cotyledons and leaves of the selected lines were also low, often by three or more orders of magnitude, compared with the unselected parent. The flea beetle, Phyllotreta cruciferae Goeze, and the diamondback moth, Plutella xylostella (L.), (both crucifer specialists) fed at equal rates on B. juncea and its low-glucosinolate lines, indicating that these species are insensitive to sinigrin and suggesting that their pest status on low-glucosinolate lines of B. juncea will likely remain unchanged. By contrast, the bertha armyworm, Mamestra configurata Wlk. (a generalist) fed up to fivefold more on the leaves of low-glucosinolate lines, suggesting that its pest status on low-glucosinolate B. juncea is likely to worsen relative to the mustard B. juncea. Flea beetles, diamondback moth, and the bertha armyworm fed at equal rates on the mustard S. alba and a low-glucosinolate line indicating that the status of these pests on low-glucosinolate S. alba will unlikely be much different from the mustard S. alba.Lines of S. alba differing in their sinalbin concentration by 1000-fold had equal levels of antixenosis resistance in their cotyledons against flea beetles, leaving little doubt that this resistance is independent of glucosinolates. Flea beetle resistance was also detected in the cotyledons of a low-glucosinolate line of B. juncea. The resistance was not detected in the parental line or in another low-glucosinolate line and appears to have arisen fortuitously during crossing and selection. Since resistance occurs in a line with concentrations of sinigrin three or more orders of magnitude lower than non-resistant lines, this resistance is also unlikely to be glucosinolate based. The mustards S. alba and B. juncea are a useful source of cotyledon resistance against flea beetles that is compatible with the aims of oilseed breeding. Key words: Glucosinolate, Brassica juncea, Sinapis alba, Phyllotreta cruciferae, Plutella xylostella, Mamestra configurata, resistance, mustard, canola, insect