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Allan T. Showler - One of the best experts on this subject based on the ideXlab platform.
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Boll weevil invasion process in Argentina
Journal of Pest Science, 2011Co-Authors: Mariano Pablo Grilli, Marina Anabel Bruno, María Laura Pedemonte, Allan T. ShowlerAbstract:The Boll weevil, Anthonomus grandis grandis Boheman, is the most destructive cotton pest in the Western Hemisphere. In 1993, the pest was reported in Argentina, and in 1994 Boll Weevils were captured in cotton fields in Formosa Province on the border between Argentina and Paraguay. The pest has subsequently moved to new areas, and in 2006 it was reported in Argentina’s main cotton growing region. This study describes the first stage of the Boll weevil invasion into areas of Argentina using a network of pheromone traps from 1997 to 2000 in Pilcomayo and Pilagas departments. A temporal autocorrelation analysis of the numbers of collected Boll Weevils in seven localities, and a synchrony analysis of 70 rural settlements for the 1997–2000 period, were the approaches we used to characterize Boll weevil dispersal and establishment. Total abundances of Boll Weevils varied but a positive correlation between total number of individuals captured and the number of traps that captured them was detected. While short term temporal autocorrelation was observed, spatial synchrony was not found. The role of alternative hosts in facilitating the advance of Boll Weevils into Argentina is discussed.
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Do Boll Weevils Really Diapause
American Entomologist, 2010Co-Authors: Allan T. ShowlerAbstract:Boll weevil, Anthonomus grandis grandis Boheman, diapause has been poorly understood since the term was first applied 50 yr ago to the pest's winter dormancy in temperate regions. In this literature-based study, I found that low temperatures and changes in photoperiod are the Boll weevil diapause-induction factors most often referred to by scientists. Studies to test the influences of those factors, however, commonly rely on weak or erroneous assumptions about selected criteria for determining diapause that have been widely, and perhaps too quickly, accepted. Although declining temperatures are associated with reduced metabolic and locomotory activity and, under field conditions, with seeking shelter, the capacity of temperature to induce diapause status in Boll Weevils is contentious largely because of confusing, sometimes contradictory, experimental findings. Results for assessing the influence of photoperiod on diapause induction are also confounded by the same weak diapause characteristics. Other studies have shown that egg production does not cease under any photoperiod regime, and that active subtropical winter populations reproduce. Diapause as an overwintering modality for Boll Weevils may have been claimed prematurely and preserved in dogma. Rather, Boll weevil dormancy during temperate winters appears to comprise a temperature-related slowing of metabolism and locomotion until a threshold is reached for quiescence. The tropical origin of the Boll weevil and high overwinter mortality in temperate regions suggest that it did not evolve to endure cold winters and thus may not have developed a true diapause response.
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longevity and egg development of adult female Boll Weevils fed exclusively on different parts and stages of cotton fruiting bodies
Entomologia Experimentalis Et Applicata, 2008Co-Authors: Allan T. ShowlerAbstract:The capacities of the rind (i.e., the developing calyx and petals of squares; and the outer casing, or husk, of Bolls) and the internal reproductive portion of cotton, Gossypium hirsutum L. (Malvaceae), squares of three sizes, and Bolls of three ages to influence adult female Boll weevil, Anthonomus grandis grandis Boheman (Coleoptera: Curculionidae), longevity and egg production were evaluated in laboratory bioassays. While feeding on the reproductive portion of squares was expected to support adult Boll Weevils for considerable periods of time (e.g., medium square reproductive portion: ≈ 185 days), feeding on rinds also resulted in substantial longevity (e.g., medium square rind: ≈ 120 days). As anticipated, feeding on the reproductive portion of squares resulted in formation of chorionated eggs in mated females, but a diet comprised exclusively of rinds, particularly from large squares, was associated with gravidity and high fecundity relative to rinds of young and mature Bolls. The reproductive portion and rind of post-bloom and young Bolls as sources of food resulted in limited gravidity while mature Bolls were not associated with any egg formation. These findings further our understanding of how Boll Weevils feed on different parts of the cotton plant and how those parts as food sources are related to the biology and ecology of the Boll weevil.
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Subtropical Boll weevil ecology
American Entomologist, 2007Co-Authors: Allan T. ShowlerAbstract:Although a great deal of research has been conducted on the Boll weevil, Anthonomus grandis grandis Boheman, originally a Mesoamerican insect, in temperate cotton, Gossypium hirsutum L., growing regions of the United States, relatively little is known about Boll weevil ecology in the subtropics and tropics, which extend from South Texas to Argentina. Unlike in temperate regions, Boll Weevils do not necessarily diapause in the subtropics. Rather, they are active and can reproduce year-round provided that adequate host plants are available. Instead of predators (excluding limited areas where the imported fire ant, Solenposis invicta Buren, has become established) and cold winter temperatures being key factors behind Boll weevil population dynamics, the availability and quality of food sources are most important. During the cotton-growing season, Boll weevil populations respond to the changing quality of the cotton plant, and component parts, which can profoundly affect gravidity, fecundity, and longevity, and susceptibility on the plant to injury from both feeding and oviposition. Immature Boll Weevils developing within fallen squares are often killed by heat and associated desiccation unless they are buried and insulated by in-season cultivation. During and after harvest operations, substantial numbers of Boll Weevils remain in the field, presumably in cotton plant debris, including fallen squares and Bolls. Although heat and desiccation also kill these Weevils until conditions cool as the typically mild subtropical winters approach, Weevils inside fruiting bodies on the soil surface can survive better than those buried by tillage. In the subtropics, Boll Weevils can reproduce during winters on volunteer cotton plants and a limited number of malvaceous plant species. Overwinter survival, however, is likely facilitated more by nutritious food sources enabling longevity that spans the cotton-free period. Some common subtropical food sources that can sustain adult Boll Weevils in this way are the endocarps of oranges, Citrus sinensis (L.) Osbeck.; grapefruit, C. paradisi Macfad.; and prickly pear, Opuntia engelmannii Salm-Dyck ex. Engel.; and other such food sources are possible. Although some researchers have maintained that Boll Weevils “migrate,” long-distance Boll weevil movement during the off-season is probably passive and opportunistic because nutritious food sources for overwintering already exist in most subtropical cotton-growing areas. Instead, Boll Weevils generally remain in the area, surviving winter in citrus orchards, and possibly other places where nutritious food is available. Flaws with the efficiency of the commonly used Boll weevil trap design, and the field sampling method used in South Texas (and possibly other areas) are discussed, as well as weaknesses of the Boll weevil spray regime that relies on pre-emptive sprays and sprays triggered by thresholds determined by sampling randomly-selected cotton squares. An alternative, proactive spray approach based on the relationship of Boll weevil populations to the changing nutritional quality of cotton fruiting bodies is described, as well as other potential in-season and off-season control tactics, including careful choice of planting date, burial of post-harvest cotton debris, citrus orchard sanitation, and mass-trapping for adult Boll Weevils in overwintering “hot spots” where Boll Weevils accumulate until cotton is planted in the spring.
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Common subtropical and tropical nonpollen food sources of the Boll weevil (Coleoptera: Curculionidae).
Environmental entomology, 2007Co-Authors: Allan T. Showler, Veronica AbrigoAbstract:It is known that substantial Boll weevil, Anthonomus grandis grandis Boheman, individuals can survive mild subtropical winters in some habitats, such as citrus orchards. Our study shows that endocarp of the fruit from prickly pear cactus, Opuntia engelmannii Salm-Dyck ex. Engel.; orange, Citrus sinensis L. Osbeck.; and grapefruit, Citrus paradisi Macfad., can sustain newly emerged adult Boll Weevils for >5 mo, which is the duration of the cotton-free season in the subtropical Lower Rio Grande Valley of Texas and other cotton-growing areas in the Western Hemisphere. Cotton, Gossypium hirsutum L., and the Boll weevil occur in the same areas with one or all three plant species (or other citrus and Opuntia species that might also nourish Boll Weevils) from south Texas to Argentina. Although adult Boll Weevils did not produce eggs when fed exclusively on the endocarps of prickly pear, orange, or grapefruit, these plants make it possible for Boll Weevils to survive from one cotton growing season to the next, which could pose challenges to eradication efforts.
R J Coleman - One of the best experts on this subject based on the ideXlab platform.
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reproductive potential of field collected overwintering Boll Weevils coleoptera curculionidae fed on pollen in the laboratory
Insect Science, 2009Co-Authors: Shoil M. Greenberg, J.s. Armstrong, Gretchen D. Jones, Mamoudou Setamou, R J Coleman, John J Adamczyk, Frank A Eischen, Tongxian LiuAbstract:The reproductive potential of overwintering Boll weevil, Anthonomus grandis grandis (Boheman), females collected from pheromone traps in September, November and January, fed for 1, 3, and 5 weeks on plant pollens, and then provided cotton squares, was determined in the laboratory at 27 ± 1 ◦ C, 65% RH, and a photoperiod 13 : 11 (L : D) h. Duration of pollen feeding by overwintering Boll Weevils did not significantly influence egg and feeding punctures, or puncture ratios (egg to total punctures) for any of the three months of parent weevil collections when provided cotton squares on a daily basis. However, punctures and puncture ratios are significantly different when comparing mean data between months of Boll weevil collections. When Boll Weevils were provided with cottonsquaresdaily,thepre-ovipositionalperiodsoffemaleparentscapturedinSeptember, November and January were 5, 9 and 14 days, respectively. The rate of eggs by females was significantly lower during November and January than September. Female parents collected in September produced a significantly higher percentage of eggs yielding adult progeny than those collected in November and January. Life table parameters indicated that net reproductive rate (Ro) of Boll weevil females collected in September was 1.2- fold higher than those collected in November and 10.7-fold higher than those collected in January. Except for testes size, no differences in male reproductive parameters were observed during the cotton-free period compared with males captured during mid-cotton (June). The number of oocytes in the ovarioles and the number of oocytes containing yolk were significantly lower during September, November and January compared with June. The reproductive potential of overwintering Boll weevil females collected in different months is an important consideration in determining the success of any control strategy.
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reproductive potential of overwintering f1 and f2 female Boll Weevils coleoptera curculionidae in the lower rio grande valley of texas
Environmental Entomology, 2007Co-Authors: Shoil M. Greenberg, J.s. Armstrong, Thomas W Sappington, Mamoudou Setamou, R J Coleman, Tongxian LiuAbstract:The feeding and oviposition activity of overwintering Boll Weevils, Anthonomus grandis grandis (Boheman), and seasonal fluctuations in development, survival, and reproduction of progeny of overwintering and first- and second-generation Boll weevil females were determined in the laboratory at 27°C, 65% RH, and a photoperiod of 12:12 (L:D) h. During the cotton-free period in the Lower Rio Grande Valley, female Boll Weevils without access to cotton resorb their unlaid eggs and enter reproductive diapause. However, when they were provided daily with greenhouse-grown cotton squares, commencement of oviposition began after 7, 15, or 20 d, depending on when they were captured. Females captured later in the winter fed longer before laying eggs than those captured in the early fall, suggesting that it may take females longer to terminate diapause the longer they have been dormant. The rate of feeding by females was significantly less during the winter months, and this may have affected the rate of diet-mediated termination of dormancy. Females of the first and second generations after the overwintering generation produced a significantly higher percentage of progeny surviving to adulthood and a higher proportion of these progeny were females. Offspring development time from overwintering female parents was significantly longer than that from first and second generations under the same laboratory conditions. The total number of lifetime eggs produced by females of the second generation during the cotton-growing season were ≈9.9-fold higher than for overwintering females and 1.5-fold higher than for first-generation females. Life table calculations indicated that the population of second-generation Boll Weevils increased an average of 1.5-fold higher each generation than for females of the first generation and 22.6-fold higher than for overwintering females. Our data showed variation in Boll weevil survival, development, and reproductive potential among the overwintering and first- and second-generation females, suggesting inherent seasonal fluctuations in these parameters.
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population dynamics of overwintering Boll Weevils anthonomus grandis grandis boheman in the lower rio grande valley of texas
2004Co-Authors: S M Greenberg, T W Sappington, R J ColemanAbstract:Survival, morphological, physiological, and reproductive changes in overwintering Boll Weevils, Anthonomus grandis grandis Boheman, in the Lower Rio Grande Valley of Texas were studied. The number of Boll Weevils captured per trap declined significantly from the postharvest period to the beginning of the spring over two overwintering seasons: 2000-2001 and 2001-2002. The proportion of males and females trapped did not differ significantly. Ninety percent of captured Weevils died within 47.6 days when fed, while 90% of unfed Weevils died after 9.0 days. This trend was not affected by month of capture. Female weevil fat body ratings were significantly greater at the beginning of fall than in the spring, while most male Weevils from September through March were rated as lean (82.5-100%). No differences in male reproductive parameters were observed in those captured during the cotton free-period compared with the middle of growing cotton season (June), except for testes size which was larger during the latter period. The percentage of females with oocytes in their ovarioles, and the percentage containing oocytes with yolk, were significantly lower in September than in June. During October-March, we did not observe any females with chorionated eggs, whereas in June 96% females contained them. We found that weevil females can oviposit eggs in the Lower Rio Grande Valley during the overwintering period after feeding 7-20 days on a reproductive diet of cotton squares. Females captured later in the winter fed at longer period before laying eggs.
Shoil M. Greenberg - One of the best experts on this subject based on the ideXlab platform.
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reproductive potential of field collected overwintering Boll Weevils coleoptera curculionidae fed on pollen in the laboratory
Insect Science, 2009Co-Authors: Shoil M. Greenberg, J.s. Armstrong, Gretchen D. Jones, Mamoudou Setamou, R J Coleman, John J Adamczyk, Frank A Eischen, Tongxian LiuAbstract:The reproductive potential of overwintering Boll weevil, Anthonomus grandis grandis (Boheman), females collected from pheromone traps in September, November and January, fed for 1, 3, and 5 weeks on plant pollens, and then provided cotton squares, was determined in the laboratory at 27 ± 1 ◦ C, 65% RH, and a photoperiod 13 : 11 (L : D) h. Duration of pollen feeding by overwintering Boll Weevils did not significantly influence egg and feeding punctures, or puncture ratios (egg to total punctures) for any of the three months of parent weevil collections when provided cotton squares on a daily basis. However, punctures and puncture ratios are significantly different when comparing mean data between months of Boll weevil collections. When Boll Weevils were provided with cottonsquaresdaily,thepre-ovipositionalperiodsoffemaleparentscapturedinSeptember, November and January were 5, 9 and 14 days, respectively. The rate of eggs by females was significantly lower during November and January than September. Female parents collected in September produced a significantly higher percentage of eggs yielding adult progeny than those collected in November and January. Life table parameters indicated that net reproductive rate (Ro) of Boll weevil females collected in September was 1.2- fold higher than those collected in November and 10.7-fold higher than those collected in January. Except for testes size, no differences in male reproductive parameters were observed during the cotton-free period compared with males captured during mid-cotton (June). The number of oocytes in the ovarioles and the number of oocytes containing yolk were significantly lower during September, November and January compared with June. The reproductive potential of overwintering Boll weevil females collected in different months is an important consideration in determining the success of any control strategy.
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Cotton Pollen Retention in Boll Weevils: A Laboratory Experiment
Palynology, 2009Co-Authors: Gretchen D. Jones, Shoil M. GreenbergAbstract:Abstract Cotton pollen is thought to exist in the gut of Boll Weevils for at least 24 hours. Because finding whole or broken cotton pollen grains are valuable clues in determining when Boll Weevils were living in cotton, the retention of cotton pollen in the gut of the weevil was examined. Boll Weevils were fed cotton buds, cotton flowers, and water for five days, then they were placed into cleaned cages without any food. However they were allowed to drink water freely. Weevils were examined at 0, 24, 48, 72, 96, and 120 hours after the buds and flowers were removed. One hundred Weevils were dissected at each time interval, and each gut was placed onto a glass slide. Light microscopy was used to determine the presence or absence of cotton pollen. More Weevils (63%) at 0 hours contained pollen than Weevils at any other interval. Whole pollen grains were not found in Weevils after 24 hours. The 120 hour interval contained a single weevil with pollen. In the laboratory test, whole cotton pollen grains indica...
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reproductive potential of overwintering f1 and f2 female Boll Weevils coleoptera curculionidae in the lower rio grande valley of texas
Environmental Entomology, 2007Co-Authors: Shoil M. Greenberg, J.s. Armstrong, Thomas W Sappington, Mamoudou Setamou, R J Coleman, Tongxian LiuAbstract:The feeding and oviposition activity of overwintering Boll Weevils, Anthonomus grandis grandis (Boheman), and seasonal fluctuations in development, survival, and reproduction of progeny of overwintering and first- and second-generation Boll weevil females were determined in the laboratory at 27°C, 65% RH, and a photoperiod of 12:12 (L:D) h. During the cotton-free period in the Lower Rio Grande Valley, female Boll Weevils without access to cotton resorb their unlaid eggs and enter reproductive diapause. However, when they were provided daily with greenhouse-grown cotton squares, commencement of oviposition began after 7, 15, or 20 d, depending on when they were captured. Females captured later in the winter fed longer before laying eggs than those captured in the early fall, suggesting that it may take females longer to terminate diapause the longer they have been dormant. The rate of feeding by females was significantly less during the winter months, and this may have affected the rate of diet-mediated termination of dormancy. Females of the first and second generations after the overwintering generation produced a significantly higher percentage of progeny surviving to adulthood and a higher proportion of these progeny were females. Offspring development time from overwintering female parents was significantly longer than that from first and second generations under the same laboratory conditions. The total number of lifetime eggs produced by females of the second generation during the cotton-growing season were ≈9.9-fold higher than for overwintering females and 1.5-fold higher than for first-generation females. Life table calculations indicated that the population of second-generation Boll Weevils increased an average of 1.5-fold higher each generation than for females of the first generation and 22.6-fold higher than for overwintering females. Our data showed variation in Boll weevil survival, development, and reproductive potential among the overwintering and first- and second-generation females, suggesting inherent seasonal fluctuations in these parameters.
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effects of burial and soil condition on postharvest mortality of Boll Weevils coleoptera curculionidae in fallen cotton fruit
Journal of Economic Entomology, 2004Co-Authors: Shoil M. Greenberg, Thomas W Sappington, A T Showler, J M BradfordAbstract:Effects of soil condition and burial on Boll weevil, Anthonomus grandis grandis Boheman, mortality in fallen cotton, Gossypium hirsutum L., fruit were assessed in this study. During hot weather immediately after summer harvest operations in the Lower Rio Grande Valley of Texas, burial of infested fruit in conventionally tilled field plots permitted significantly greater survival of Weevils than in no-tillage plots. Burial of infested squares protected developing Weevils from heat and desiccation that cause high mortality on the soil surface during and after harvest in midsummer and late summer. A laboratory assay showed that burial of infested squares resulted in significantly greater weevil mortality in wet than in dry sandy or clay soils. Significantly fewer Weevils rose to the soil surface after burial of infested Bolls during winter compared with Bolls set on the soil surface, a likely result of wetting by winter rainfall. A combination of leaving infested fruit exposed to heat before the onset of cooler winter temperatures and burial by tillage when temperatures begin to cool might be an important tactic for reducing populations of Boll Weevils that overwinter in cotton fields.
Tongxian Liu - One of the best experts on this subject based on the ideXlab platform.
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reproductive potential of field collected overwintering Boll Weevils coleoptera curculionidae fed on pollen in the laboratory
Insect Science, 2009Co-Authors: Shoil M. Greenberg, J.s. Armstrong, Gretchen D. Jones, Mamoudou Setamou, R J Coleman, John J Adamczyk, Frank A Eischen, Tongxian LiuAbstract:The reproductive potential of overwintering Boll weevil, Anthonomus grandis grandis (Boheman), females collected from pheromone traps in September, November and January, fed for 1, 3, and 5 weeks on plant pollens, and then provided cotton squares, was determined in the laboratory at 27 ± 1 ◦ C, 65% RH, and a photoperiod 13 : 11 (L : D) h. Duration of pollen feeding by overwintering Boll Weevils did not significantly influence egg and feeding punctures, or puncture ratios (egg to total punctures) for any of the three months of parent weevil collections when provided cotton squares on a daily basis. However, punctures and puncture ratios are significantly different when comparing mean data between months of Boll weevil collections. When Boll Weevils were provided with cottonsquaresdaily,thepre-ovipositionalperiodsoffemaleparentscapturedinSeptember, November and January were 5, 9 and 14 days, respectively. The rate of eggs by females was significantly lower during November and January than September. Female parents collected in September produced a significantly higher percentage of eggs yielding adult progeny than those collected in November and January. Life table parameters indicated that net reproductive rate (Ro) of Boll weevil females collected in September was 1.2- fold higher than those collected in November and 10.7-fold higher than those collected in January. Except for testes size, no differences in male reproductive parameters were observed during the cotton-free period compared with males captured during mid-cotton (June). The number of oocytes in the ovarioles and the number of oocytes containing yolk were significantly lower during September, November and January compared with June. The reproductive potential of overwintering Boll weevil females collected in different months is an important consideration in determining the success of any control strategy.
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reproductive potential of overwintering f1 and f2 female Boll Weevils coleoptera curculionidae in the lower rio grande valley of texas
Environmental Entomology, 2007Co-Authors: Shoil M. Greenberg, J.s. Armstrong, Thomas W Sappington, Mamoudou Setamou, R J Coleman, Tongxian LiuAbstract:The feeding and oviposition activity of overwintering Boll Weevils, Anthonomus grandis grandis (Boheman), and seasonal fluctuations in development, survival, and reproduction of progeny of overwintering and first- and second-generation Boll weevil females were determined in the laboratory at 27°C, 65% RH, and a photoperiod of 12:12 (L:D) h. During the cotton-free period in the Lower Rio Grande Valley, female Boll Weevils without access to cotton resorb their unlaid eggs and enter reproductive diapause. However, when they were provided daily with greenhouse-grown cotton squares, commencement of oviposition began after 7, 15, or 20 d, depending on when they were captured. Females captured later in the winter fed longer before laying eggs than those captured in the early fall, suggesting that it may take females longer to terminate diapause the longer they have been dormant. The rate of feeding by females was significantly less during the winter months, and this may have affected the rate of diet-mediated termination of dormancy. Females of the first and second generations after the overwintering generation produced a significantly higher percentage of progeny surviving to adulthood and a higher proportion of these progeny were females. Offspring development time from overwintering female parents was significantly longer than that from first and second generations under the same laboratory conditions. The total number of lifetime eggs produced by females of the second generation during the cotton-growing season were ≈9.9-fold higher than for overwintering females and 1.5-fold higher than for first-generation females. Life table calculations indicated that the population of second-generation Boll Weevils increased an average of 1.5-fold higher each generation than for females of the first generation and 22.6-fold higher than for overwintering females. Our data showed variation in Boll weevil survival, development, and reproductive potential among the overwintering and first- and second-generation females, suggesting inherent seasonal fluctuations in these parameters.
Thomas W Sappington - One of the best experts on this subject based on the ideXlab platform.
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reproductive potential of overwintering f1 and f2 female Boll Weevils coleoptera curculionidae in the lower rio grande valley of texas
Environmental Entomology, 2007Co-Authors: Shoil M. Greenberg, J.s. Armstrong, Thomas W Sappington, Mamoudou Setamou, R J Coleman, Tongxian LiuAbstract:The feeding and oviposition activity of overwintering Boll Weevils, Anthonomus grandis grandis (Boheman), and seasonal fluctuations in development, survival, and reproduction of progeny of overwintering and first- and second-generation Boll weevil females were determined in the laboratory at 27°C, 65% RH, and a photoperiod of 12:12 (L:D) h. During the cotton-free period in the Lower Rio Grande Valley, female Boll Weevils without access to cotton resorb their unlaid eggs and enter reproductive diapause. However, when they were provided daily with greenhouse-grown cotton squares, commencement of oviposition began after 7, 15, or 20 d, depending on when they were captured. Females captured later in the winter fed longer before laying eggs than those captured in the early fall, suggesting that it may take females longer to terminate diapause the longer they have been dormant. The rate of feeding by females was significantly less during the winter months, and this may have affected the rate of diet-mediated termination of dormancy. Females of the first and second generations after the overwintering generation produced a significantly higher percentage of progeny surviving to adulthood and a higher proportion of these progeny were females. Offspring development time from overwintering female parents was significantly longer than that from first and second generations under the same laboratory conditions. The total number of lifetime eggs produced by females of the second generation during the cotton-growing season were ≈9.9-fold higher than for overwintering females and 1.5-fold higher than for first-generation females. Life table calculations indicated that the population of second-generation Boll Weevils increased an average of 1.5-fold higher each generation than for females of the first generation and 22.6-fold higher than for overwintering females. Our data showed variation in Boll weevil survival, development, and reproductive potential among the overwintering and first- and second-generation females, suggesting inherent seasonal fluctuations in these parameters.
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using genetic markers and population assignment techniques to infer origin of Boll Weevils coleoptera curculionidae unexpectedly captured near an eradication zone in mexico
Environmental Entomology, 2006Co-Authors: Kyung Seok Kim, Pedro Canorios, Thomas W SappingtonAbstract:Several Boll Weevils, Anthonomus grandis Boheman, were captured in pheromone traps in 2004 near Tlahualilo, Durango, Mexico, an area where none had been reported for ≈10 yr. It is possible that they were from an endemic population normally too low in numbers to be detected but that increased in response to more favorable rainfall conditions in 2004. Alternatively, they may represent an influx of migrants or the immediate descendents of migrants. To identify the most likely origin of the Boll Weevils captured in this area, we characterized microsatellite variation of the Tlahualilo Weevils and compared it with the variation from three other populations in northern Mexico and from one in southern Texas. Measures of gene flow and individual assignment tests suggest that the Boll Weevils captured near Tlahualilo were primarily from an endemic low-level population, but that this area also is receiving immigrants from a cotton growing region ≈200 km to the north, near Rosales, Chihuahua, which is currently under a Boll weevil eradication program. Similarly, Rosales is receiving immigrants from Tlahualilo. This study shows that microsatellite markers and population assignment techniques will be practical tools for determining the most likely origins of Boll Weevils reintroduced to eradication zones in the United States and Mexico. Population assignment strategies based on genetic markers hold promise for replacing conventional, but spatially constrained, mark-recapture studies of insect dispersal. This relatively new and powerful analytical approach is widely used in conservation genetics and fisheries studies, but has been underused by entomologists.
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dispersal of Boll Weevils coleoptera curculionidae from cotton modules before ginning
Journal of Economic Entomology, 2006Co-Authors: Thomas W Sappington, Alan D Brashears, Megha N Parajulee, Stanley C Carroll, Mark D Arnold, Allen E Knutson, John W NormanAbstract:Abstract We characterized the level of risk of Boll weevil, Anthonomus grandis grandis Boheman, reintroduction to an eradication zone posed by dispersal from cotton modules during and after transport to the gin. Mark–release-recapture experiments in August and September in Texas indicated that most Weevils disperse rapidly from the module surface, temperature permitting, unless confined under a module tarp, where most died. Nevertheless, 1–5% of released Weevils were recovered alive after 24 h on the side and top surfaces of modules, representing potential dispersants. Mortality of Boll Weevils caged on the top surface of a module was 95–100% after 1–4 d when maximum air temperatures were ≥33°C and 72–100% when minimum temperatures were −7°C or lower, but a few survived even after experiencing a minimum daily temperature of −12°C. Under warm (daily maximum temperatures ≥25°C) and cold (daily minimum temperatures ≤0°C) weather conditions, survival was higher under the tarp than on the open surface of the m...
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potential for escape of live Boll Weevils coleoptera curculionidae into cottonseed motes and cleaned lint at the cotton gin
Journal of Economic Entomology, 2004Co-Authors: Thomas W Sappington, Alan D Brashears, Megha N Parajulee, Stanley C Carroll, Mark D Arnold, Roy V BakerAbstract:Reintroductions of the Boll weevil, Anthonomus grandis grandis Boheman, into areas of the United States where it has been eradicated or suppressed are very expensive to mitigate. There is concern that a cotton gin in an eradication zone may serve as a site of Boll weevil reintroductions when processing cotton harvested in a neighboring infested zone. Similarly, there is a question whether weevil-free areas can safely import gin products, such as cottonseed and baled lint, from infested areas without risking an introduction. Many countries require fumigation of imported U.S. cotton bales to protect against Boll weevil introductions, costing the U.S. cotton industry millions of dollars annually. In previously reported experiments, we quantified the potential for Boll Weevils to survive passage through precleaning machinery in the gin. In this study, we quantified survival potential of Boll Weevils passing through the gin stand and segregating into the cottonseed, mote, or lint fractions. We also examined Boll weevil survival when passed with ginned lint through a lint cleaner. We present a flow chart of experimentally determined survival potentials of Boll Weevils passing through the various subprocesses of the gin, from which one can calculate the risk of a live Boll weevil reaching any point in the process. Our data show that there is virtually no chance of a Boll weevil being segregated alive into the cottonseed or of one surviving in the lint to approach the bale press. Therefore, quarantine or fumigation of cottonseed and cotton bales to guard against Boll weevil introductions is unnecessary.
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potential for transport of Boll Weevils coleoptera curculionidae to the cotton gin within cotton modules
Journal of Economic Entomology, 2004Co-Authors: Thomas W Sappington, Alan D Brashears, Megha N Parajulee, Stanley C Carroll, Mark D Arnold, John W Norman, Allen E KnutsonAbstract:There is concern that cotton gins located in Boll weevil, Anthonomus grandis grandis Boheman, eradication zones serving customers in adjacent infested zones may serve as a site for Boll weevil reintroductions if Weevils are transported alive inside cotton modules. We surveyed fields in three distinct areas of Texas and found that Weevils can be present in large numbers in cotton fields that have been defoliated and desiccated in preparation for harvest, both as free adults and as immatures inside unopened Bolls. Harvested cotton taken from module builders indicated that ≈100–3,700 adult Boll Weevils were packed inside modules constructed at the sampled fields. Marked Weevils were forced through a laboratory field cleaner (bur extractor) commonly mounted on stripper-harvesters, and 14% were recovered alive in the seed cotton fraction and lived at least to 24 h. Survival of Weevils placed inside modules declined over time up to 7 d, but the magnitude of the decline varied with experimental conditions. In one experiment, 91% of the Weevils survived to 7 d, whereas under harsher environmental conditions, only 11% survived that long. Together, our results indicate that when cotton is harvested in an infested area, Boll Weevils likely will be packed alive into cotton modules, and many will still be alive by the time the module is fed into the gin, at least up to 7 d after the module’s construction.