Comparison of three dispenser distribution patterns for pheromone mating disruption of Paralobesia viteana (Lepidoptera: Tortricidae) in vineyards

Over two growing seasons, Isomate GBM-Plus tube-type dispensers releasing the major pheromone component of grape berry moth, Paralobesia viteana (Clemens) (Lepidoptera: Tortricidae), were evaluated in vineyards (Vitis spp.) in Michigan, New York, and Pennsylvania. Dispensers were deployed in three different density-arrangement treatments: 124 dispensers per ha, 494 dispensers per ha, and a combined treatment with 124 dispensers per ha in the vineyard interior and 988 dispensers per ha at the vineyard border, equivalent to an overall density of 494 dispensers per ha. Moth captures and cluster infestation levels were compared at the perimeter and interior of vineyards receiving these different pheromone treatments and in vineyards receiving no pheromone. Orientation of male moths to pheromone-baited traps positioned at the perimeter and interior of vineyards was reduced as a result of mating disruption treatments compared with the nontreated control. These findings were consistent over both years of the study. Disruption of male moth captures in traps varied from 93 to 100% in treated vineyards, with the 494 dispensers per ha application rates providing significantly higher level of disruption than the 124 dispensers per ha rate, but only in 2007. Measurements of percentage of cluster infestation indicated much higher infestation at perimeters than in the interior of the vineyards in all three regions, but in both sample positions there was no significant effect of dispenser density on cluster infestation levels in either year. The contrasting results of high disruption of moth orientation to traps in vineyards that also had low levels of crop protection from this pheromone treatment are discussed in the context of strategies to improve mating disruption of this tortricid pest.     

梨园芳香植物间作区节肢动物群落时序格局

以沙地梨园间作罗勒、孔雀草、薄荷为处理,自然生草和清耕区为对照,应用最优分割法和模糊聚类法,探讨梨园节肢动物群落、害虫亚群落和天敌亚群落发生的时序格局特征及其相互联系。结果表明:总群落、害虫亚群落以及其优势种个体数时序变化趋势呈偏态分布,而天敌亚群落以及其优势种个体数的呈正态分布,高峰期出现在6月末至7月中旬,比总群落和害虫亚群落个体数发生高峰晚。在梨树年生长周期的主要时段中,芳香植物间作区较自然生草区、清耕区害虫亚群落的发生数量(4月中至8月底)少;而天敌亚群落发生数量(4月底至6月底)多。梨园各间作区节肢动物总群落和害虫亚群落时序最优格局均可划分5个时段:发展初期、发展期、稳定期、波动期和衰退期;天敌亚群落分为3个时段:发展期、稳定期、衰退期。但处理间在发生时段的时间范围、发生数量及组成特征上存在复杂的差异。梨园节肢动物总群落、害虫亚群落、天敌亚群落时序聚类结果不同,预示着处理间节肢动物总群落、害虫亚群落和天敌亚群落在各发生时段上的个体组成、物种丰富度、群落多样性指数、优势度和均匀度指数存在着差异。     

Habitat functionality for the ecosystem service of pest control: reproduction and feeding sites of pests and natural enemies

• 1 Landscape management for enhanced natural pest control requires knowledge of the ecological function of the habitats present in the landscape mosaic. However, little is known about which habitat types in agricultural landscapes function as reproduction habitats for arthropod pests and predators during different times of the year.
• 2 We studied the arthropod assemblage on six crops and on the seven most abundant native plant species in two landscapes over 1 year in Australia. Densities of immature and adult stages of pests and their predators were assessed using beat sheet sampling.
• 3 The native plants supported a significantly different arthropod assemblage than crops. Native plants had higher predator densities than crops over the course of the year, whereas crops supported higher pest densities than the native plants in two out of four seasonal sampling periods. Crops had higher densities of immature stages of pests than native plants in three of four seasonal sampling periods, implying that crops are more strongly associated with pest reproduction than native plants. Densities of immature predators, excluding spiders, were not different between native plants and crops. Spiders were, however, generally abundant and densities were higher on native plants than on crops but, because some species disperse when immature, there is less certainty in identifying their reproduction habitat.
• 4 Because the predator to pest ratio on native plant species showed little variation, and spatial variation in arthropod assemblages was limited, the predator support function of native vegetation may be a general phenomenon. Incentives that maintain and restore native remnant vegetation can increase the predator to pest ratio at the landscape scale, which could enhance pest suppression in crops.

     

Surface-active arthropods in organic vineyards,integrated vineyards and natural habitat in the Cape Floristic Region

The Cape Floristic Region (CFR), South Africa, is a biodiversity hotspot challenged by intensive wine production. Innovative approaches are being explored to optimize wine production without compromising biodiversity. As organic farming enhances biodiversity conservation in many other regions, the aim here was to assess the potential of organic vineyard management for conserving CFR soil surface arthropod diversity. Pitfall traps were used to sample arthropods in three study areas, each of which included an organic vineyard, an integrated vineyard and a natural vegetation reference habitat. Overall arthropod morphospecies richness was highest in natural sites, followed by organic vineyards and then integrated vineyards. The same trend was seen for predators, saprophages and phytophages. The ability of organic vineyards to sustain more morphospecies than integrated vineyards were partially due to higher non-crop vegetation complexity and less intense management in the organic vineyards. Arthropod assemblages were similar in organic and integrated vineyards, while both land-uses differed greatly from natural sites. Variation among natural vegetation assemblages in different study areas was also much greater than among assemblages of cultivated sites. Organic vineyard management has the potential to make an important contribution to arthropod conservation in the CFR at the field scale. However, at the landscape scale, natural habitat supports a much wider variety of morphospecies, and the preservation of natural fragments in the vineyard landscape may be the most effective measure to increase biodiversity in the winelands.     

Arthropod prey of shelterbelt-associated birds: linking faecal samples with biological control of agricultural pests

Abstract  The value of insectivorous birds as agents for biological control of arthropod pests has been little studied, especially in Australia. This paper reports on the extent to which arthropods from various pest and non-pest taxa feature in the diets of birds captured in farm shelterbelts in central western New South Wales. The parameters examined were the types of arthropod fragments in bird faeces and percentage volume and frequency of occurrence of each component. The faecal data were compared with samples of the arthropod fauna trapped in shelterbelts during the period the birds were captured. In 26 of 29 faecal samples, arthropod fragments were the predominant components, the most common being from Coleoptera, Hymenoptera (especially Formicidae), Orthoptera and Araneae. The recognisable pest taxa in faecal samples were Scarabaeidae and wingless grasshopper Phaulacridium vittatum (Sjöstedt) (Orthoptera: Acrididae). The results indicate that the native bird species common in farm shelterbelts preyed on a range of arthropod taxa including several that are pests of crops and pastures. Accordingly, conservation of birds in farmlands could contribute to suppression of arthropod pests.     

Olfactory response of Typhlodromus pyri (Acari: Phytoseiidae) to synthetic methyl salicylate in laboratory bioassays

The herbivore‐induced plant volatile (HIPV) methyl salicylate (MeSA) is widely present in the chemical profile of several plant species and is known to attract natural enemies, including predatory mites. In this study, the response of Typhlodromus pyri, a key predator of pest mites in west coast vineyards, to synthetically produced MeSA was tested using a Y‐tube olfactometer in laboratory bioassays. Six doses ranging from 0.002 to 200 μg of MeSA diluted in 0.1 ml hexane were tested. Significantly higher proportions of T. pyri preferred MeSA at doses 0.02, 0.2 and 20 μg. No differences in response to MeSA were detected at the highest (200 μg), intermediate (2 μg) and lowest (0.002 μg) doses. Mite response to MeSA was a function of dose when fitting polynomial and logistic regression models using dose and square of the log dose prediction factors. Results indicate that synthetic MeSA may be applied to attract predatory arthropod populations in vineyards to enhance biological control of pest mites.     

Swede midge (Diptera: Cecidomyiidae), ten years of invasion of crucifer crops in North America

The Swede midge, Contarinia nasturtii Kieffer (Diptera: Cecidomyiidae), a common insect pest in Europe, is a newly invasive pest in North America that constitutes a major threat to cruciferous vegetable and field crops. Since its first identification in Ontario, Canada, in 2000, it has rapidly spread to 65 counties in the provinces of Ontario and Quebec and has recently been found in canola (one of two cultivars of rapeseed, Brassica napus L. and Brassica campestris L.) in the central Prairie region where the majority of Canada's 6.5 million ha (16 million acres) of canola is grown. The first detection of Swede midge in the United States was in 2004 in New York cabbage (Brassica oleracea L.), but it has now been found in four additional states. Here, we review the biology of Swede midge, its host plant range, distribution, economic impact, pest status, and management strategies. We provide insight into this insect's future potential to become an endemic pest of brassica crops in North America. We also proposed research needed to develop tactics for handling this invasive pest in brassica crops.     

Geographic variation in diapause induction: the grape berry moth (Lepidoptera: Tortricidae)

Diapause in insects occurs in response to environmental cues, such as changes in photoperiod, and it is a major adaptation by which insects synchronize their activity with biotic resources and environmental constraints. For multivoltine agricultural insect pests, diapause initiation is an important consideration in management decisions, particularly toward the end of the growing season. The grape berry moth, Paralobesia viteana (Clemens), is the main insect pest affecting viticulture, and this insect responds to postsummer solstice photoperiods to initiate diapause. Because the range of grape berry moth extends from southern Canada to the southern United States, different populations are exposed to different photoperiodic regimes. We quantified the diapause response in grape berry moth populations from Arkansas, Michigan, New York, Pennsylvania, Texas, and Virginia, and observed latitudinal variation in diapause initiation. Populations from Michigan, New York, and Pennsylvania responded significantly different than those from Arkansas, Texas, and Virginia. We also observed, as a consequence of our experiments, that the timing of our laboratory studies influenced grape berry moth's response to photoperiod, ceteris paribus. Experiments that were conducted when grape berry moth would be naturally in diapause resulted in a significant higher proportion of diapausing pupae at photoperiods (i.e., >15 h) that generally do not induce diapause, suggesting that attention should be paid to the timing of behavioral and physiological experiments on insects. This relationship between photoperiod and diapause induction in grape berry moth across geographic regions will provide applicable knowledge to improve pest management decisions.     

The effect of an invasive alien vine, <Emphasis Type="Italic">Vincetoxicum rossicum</Emphasis> (Asclepiadaceae), on arthropod populations in Ontario old fields

Vincetoxicum rossicum is an invasive alien vine introduced from Europe in the late 1800s that is now an emerging pest in upstate New York and eastern Ontario. The plant can form dense, monotypic stands in woodlots and old fields, and may be displacing native vegetation. As a consequence, V. rossicum may be displacing arthropod fauna associated with native vegetation. In June and August 2002, we sampled V. rossicum and three other old field plants (Asclepias syriaca, Solidago altissima, and mixed graminoids) for arthropods using pitfall traps and by sampling individual plants. A total of 7868 arthropods were counted on plants and 18,195 individuals were trapped; these were sorted by feeding guild. Overall, stands of V. rossicum supported the lowest abundance of both stem- and ground-dwelling individuals, as well as the lowest number of arthropods in most phytophagous guilds. Some feeding guilds are entirely absent: V. rossicum stands are completely devoid of gall-makers and miners, and support few pollinators. This study suggests that arthropod diversity will decline if V. rossicum displaces native old-field plants.     

Carbaryl resistance in populations of grape berry moth (Lepidoptera: Tortricidae) in New York and Pennsylvania

We collected grape berry moth, Endopiza viteana (Clemens) (from cultivated and wild Vitis along Lake Erie in Pennsylvania and New York), and measured carbaryl susceptibility in first instars. A model of susceptibility was based on the concentration-mortality curve of laboratory-maintained colonies originating from wild Vitis with no prior history of carbaryl exposure, and a noncommercial vineyard with modest previous exposure to carbaryl. We estimated LC50 and LC90 for susceptible grape berry moth larvae at 45.4 and 2319 microg/ml, respectively. Bioassays on field-collected larvae from commercial vineyards in both states, where grape growers were abiding by current pest management guidelines for carbaryl use, revealed carbaryl resistance ratios from 7 to 71 at the LC50 level. With the loss or restriction of alternative chemical control tactics in the Food Quality Protection Act era, resistance management programs for grape berry moth should be immediately developed and implemented to regain the efficacy of this once effective insecticide and other related chemical compounds.     

Temporal variation in arthropod sampling effectiveness: the case for using the beat sheet method in cotton

Predatory insects and spiders are key elements of integrated pest management (IPM) programmes in agricultural crops such as cotton. Management decisions in IPM programmes should to be based on a reliable and efficient method for counting both predators and pests. Knowledge of the temporal constraints that influence sampling is required because arthropod abundance estimates are likely to vary over a growing season and within a day. Few studies have adequately quantified this effect using the beat sheet, a potentially important sampling method. We compared the commonly used methods of suction and visual sampling to the beat sheet, with reference to an absolute cage clamp method for determining the abundance of various arthropod taxa over 5 weeks. There were significantly more entomophagous arthropods recorded using the beat sheet and cage clamp methods than by using suction or visual sampling, and these differences were more pronounced as the plants grew. In a second trial, relative estimates of entomophagous and phytophagous arthropod abundance were made using beat sheet samples collected over a day. Beat sheet estimates of the abundance of only eight of the 43 taxa examined were found to vary significantly over a day. Beat sheet sampling is recommended in further studies of arthropod abundance in cotton, but researchers and pest management advisors should bear in mind the time of season and time of day effects.     

Influence of flowering cover crops on Anagrus parasitoids (Hymenoptera: Mymaridae) and Erythroneura leafhoppers (Homoptera: Cicadellidae) in New York vineyards

Abstract 1 We tested the hypothesis that providing nectar‐producing cover crops will enhance the biological control of grape leafhoppers (Erythroneura spp.) by Anagrus wasps in commercial vineyards in New York, U.S.A. 2 We established three cover crops between vine rows in a commercial vineyard: buckwheat (Fagopyrum esculentum (Moench)), clover (Trifolium repens L.) and mowed sod (Dactylis glomerata L.). 3 There was no effect of cover crop on adult Anagrus in 1996, whereas in 1997 adults were more abundant within edge vines with buckwheat compared to vines with clover or sod; adults were more abundant at the vineyard edge, especially early in the season. 4 Parasitism of ‘sentinel’ leafhopper eggs was higher on vines with buckwheat compared to parasitism on vines with clover or sod in 1996; a similar, non‐significant trend, was observed in 1997. 5 Neither the abundance nor the distribution of leafhoppers was influenced by cover crops, although in 1997 there was a trend toward greater numbers of nymphs on edge vines with buckwheat. 6 In a cage experiment, parasitism by Anagrus of leafhopper eggs on grapes was greater when adults had access to flowering buckwheat rather than buckwheat without flowers. 7 In a laboratory study, longevity of female Anagrus was increased when provided with honey or sugar water compared to water only or nothing. 8 Our results suggest that parasitism of grape leafhoppers by Anagrus may be enhanced by providing floral resources within vineyards in New York, although it is unclear whether this will produce meaningful reductions in pest abundance.     

Impact of soil type, moisture, and depth on swede midge (Diptera: Cecidomyiidae) pupation and emergence

Contarinia nasturtii (Kieffer) (Diptera: Cecidomyiidae), a common insect pest in Europe and a new invasive pest in North America, causes severe damage to cruciferous crops. Currently, many counties in Canada and the United States in which C. nasturtii has not been previously reported are at risk of being infested by C. nasturtii. Effectiveness of chemical control is limited, especially under high population pressure in fields, because the cryptic habits of C. nasturtii protect them from insecticidal sprays. Alternative management strategies against C. nasturtii that are needed to protect crucifers and soil management for the pupal stage were studied as one option. Six different types of soils (loam fine sand, fine sand, clay loam, muck, Chenango shale loam, and silt loam soil) were collected from commercial cabbage fields in New York and studied in the laboratory for their impact on C. nasturtii pupation and emergence. The results indicated that extremely wet or dry soils significantly hindered C. nasturtii emergence, regardless of soil type, suggesting that soil type alone may not be a major factor regulating C. nasturtii abundance. Optimal moisture content for C. nasturtii emergence varied for different soils. Most C. nasturtii pupated within the top 1 cm of soil. Furthermore, we found that >5 cm of soil cover effectively reduced the emergence number and delayed the time of emergence. Based on these results, we suggest that soil manipulation (moisture content and cultivation practices) should be considered as an important component in an overall integrated pest management program for C. nasturtii.     

Field spray abdominal gland secretions of rove beetles: Effects on the pest abundance and arthropod community

Alternative environmentally friendly methods for pest control are in high demand because of the environmental impacts of pesticides. Notably, predator-released kairomone is a natural compound released by natural enemies, which mediates non-consumptive effects between natural enemies and prey. However, this novel pest control agent is underutilized relative to pesticides and natural enemies. Additionally, the effects of spraying predator kairomone on the number and diversity of arthropods in fields and whether this method is environmental-friendly are poorly understood. In the present study, a predator kairomone, rove beetle (Paederus fuscipes Curtis) abdominal gland secretion (AGS), was sprayed in rice fields to investigate whether AGS can suppress pest populations or will affect the fields’ arthropod communities. After AGS spraying, the abundance of arthropods decreased throughout the first 12-d period, including arthropod pests such as hemipterans (small brown planthopper, Laodelphax striatellus (Fallén), brown planthopper, Nilaparvata lugens (Stål), white-backed planthopper, Sogatella furcifera (Horváth), and leafhoppers), and lepidopterans (rice leaf folder, Cnaphalocrocis medinalis Guenée). The abundance of arthropod predators was not affected, except for predatory spiders, which decreased, and rove beetles (P. fuscipes), which increased. In the terms of arthropod diversity, neither pests nor their natural enemies were changed by AGS application. This work highlights that predator kairomone can temporarily suppress pest populations in fields but has no adverse effects on arthropod diversity; thus, this approach is environmentally friendly and can be used in real-world applications. Broadly, present studies suggest that the application of predator kairomone may have synergistic or cumulative effects on pest suppression.     

A New PCR-Based Method Shows That Blue Crabs (Callinectes sapidus (Rathbun)) Consume Winter Flounder (Pseudopleuronectes americanus (Walbaum))

Winter flounder (Pseudopleuronectes americanus) once supported robust commercial and recreational fisheries in the New York (USA) region, but since the 1990s populations have been in decline. Available data show that settlement of young-of-the-year winter flounder has not declined as sharply as adult abundance, suggesting that juveniles are experiencing higher mortality following settlement. The recent increase of blue crab (Callinectes sapidus) abundance in the New York region raises the possibility that new sources of predation may be contributing to juvenile winter flounder mortality. To investigate this possibility we developed and validated a method to specifically detect winter flounder mitochondrial control region DNA sequences in the gut contents of blue crabs. A survey of 55 crabs collected from Shinnecock Bay (along the south shore of Long Island, New York) in July, August, and September of 2011 showed that 12 of 42 blue crabs (28.6%) from which PCR-amplifiable DNA was recovered had consumed winter flounder in the wild, empirically supporting the trophic link between these species that has been widely speculated to exist. This technique overcomes difficulties with visual identification of the often unrecognizable gut contents of decapod crustaceans, and modifications of this approach offer valuable tools to more broadly address their feeding habits on a wide variety of species.     

Comparative footprint of alien, agricultural and restored vegetation on surface-active arthropods

Both invasive alien trees and agricultural conversion have major impacts on biodiversity. We studied here the comparative impact of these two types of land transformation on a wide range of surface-active arthropod species using pitfall traps, with evergreen sclerophyllous natural vegetation (fynbos) as the control. The study was in the Cape Floristic Region, a global biodiversity hotspot, where alien trees are of major concern and where vineyards replace natural fynbos vegetation. Surface-active arthropods were selected as they are species rich, relatively immobile, and occur in high abundance. We hypothesized that the impact of the two types of land cover transformation would produce similar qualitative and quantitative effects on the arthropods. We also compared the results in the transformed and natural areas with those in areas cleared of alien trees. Arthropod species richness in cleared areas was higher than in vineyards and more similar to that in natural fynbos, while alien trees had the lowest. Overall abundance scores were highest in cleared areas, closely followed by fynbos, then vineyards and lowest in alien trees. Several species were restricted to each vegetation type, including alien trees. In terms of assemblage composition, all vegetation types were significantly different, although fynbos and vineyards grouped, suggesting that vineyards have less impact on the arthropod community than do alien trees. When rare species were excluded, vineyards and cleared sites grouped, indicating some recovery but only involving those species that were common and habitat tolerant. Our results suggest that vineyards retain a greater complement of indigenous species than alien trees, but that clearing of these aliens soon encourages establishment of indigenous species. Although there were significant differences in soil moisture and litter depth within and between vegetation types, we did not record them as significantly affecting species richness or abundance, even in alien vegetation, an encouraging sign for restoration.     

转基因抗草甘膦抗虫棉对棉田冠层节肢动物群落的影响

【背景】随着转基因抗虫棉在我国的广泛种植,一种具有抗虫和耐除草剂（草甘膦）的双价棉被培育成功。这种转双价基因棉和转单价基因抗虫棉对棉田节肢动物群落结构的影响可能不同。因此,在该类转双价基因棉花进行环境释放之前,有必要研究其对棉田节肢动物群落的影响,评价其环境安全性。【方法】试验于2010年5月9日~9月23日和2011年5月10日~9月24日在河南省安阳市中国农业科学院棉花研究所试验农场进行,棉田类型有3种——转基因抗草甘膦抗虫棉田、转Bt棉田和常规棉田,每种棉田种植3个小区,每个小区面积为200 m2（8 m×25 m）。采用对角线5点取样方法,每5 d调查1次棉田的节肢动物群落,通过目测对节肢动物鉴定到属。【结果】抗草甘膦抗虫棉田、Bt棉田和常规棉田节肢动物群落、害虫亚群落和天敌亚群落的结构与组成无明显差异;抗草甘膦抗虫棉田害虫种群数量低于抗虫棉田和常规棉田,而其天敌种群数量与常规棉田相当,略低于Bt棉田;3种棉田节肢动物群落、害虫亚群落和天敌亚群落的多样性指数、均匀性指数均无明显差异。【结论与意义】种植转基因抗草甘膦抗虫棉花不会对棉田节肢动物群落组成造成显著影响。本研究为转基因抗草甘膦抗虫棉田的环境安全性评价提供了依据。     

Diversity of natural enemies in Central Otago,New Zealand apple orchards: a practical measure of sustainability in pest management?

The diversity of the arthropod fauna in apple orchards in Central Otago was recorded from 1994 to 1999 using beating trays, pitfall traps, and sticky traps and the data analysed by the Shannon–Wiener Index. Three different fruit production systems were compared, conventional (CFP), integrated (IFP), and biological (BFP), to determine whether total arthropod diversity and/or the diversity of natural enemies (predators and parasitoids) could be used to measure the sustainability of their pest management practices. The contribution of natural enemies to the diversity indices was also examined to determine if they reflected the key species essential for sustainable pest management. The diversity of natural enemies in beating trays was found to be the measure most sensitive to changes in pest management. The diversity of both the total arthropod fauna and natural enemies was much lower under CFP than under either IFP or BFP, due to the use of broad-spectrum pesticides. This practice made the CFP programme unsustainable and it is no longer used. During the transition from CFP to IFP, the diversity indices rose to become similar to that in the BFP programme by the third season. The introduction of frequent applications of fungicides in BFP, including lime sulphur, appeared to reduce total arthropod and natural enemy diversity. Falls in the diversity indices for natural enemies were shown to reflect reduced numbers, range, and evenness of natural enemies but not necessarily the key species known to be critical for sustainable pest management. It is proposed that a Shannon–Wiener Index for natural enemies in beating trays of 0.2 or less in summer is strongly indicative of unsustainable pest management in Otago apple orchards. On the other hand, indices of 0.3–0.8, as found under IFP and BFP, do not give unequivocal or quantitative indications of the sustainability of pest management. A suite of other measures of sustainability are more useful, notably combining lower pesticide use, reduced pest damage and presence at harvest, the greater roles of key natural enemies, more effective plant resistance to pests and diseases, and higher profitability.     

Expression of Bt-Cry3A in transgenic <Emphasis Type="Italic">Populus alba</Emphasis> × <Emphasis Type="Italic">P. glandulosa</Emphasis> and its effects on target and non-target pests and the arthropod community

During the growing seasons of 2006–2008, feeding tests and field studies were conducted in Beijing, China, to investigate the effects of transgenic Bacillus thuringiensis (Bt) poplar (BGA-5) expressing the Cry3A protein (0.0264–0.0326% of the total soluble protein) on target and non-target pests and the arthropod community. The effects of BGA-5 on the target pest Plagiodera versicolora (Coleoptera, Chrysomelidae) and a non-target pest Clostera anachoreta (Lepidoptera, Notodontidae), were assessed under laboratory conditions. Total mortality of P. versicolora larvae fed with BGA-5 leaves was significantly higher than that of the control (P < 0.05). The exuviation index of P. versicolora larvae fed with BGA-5 tended to be higher than that of CK, but it was not significantly different. The pupation rate and eclosion rate of the survived larvae fed with BGA-5 were lower than that of CK, but it was also not significantly different. Additionally, no significant differences were detected in the mortality, exuviations index, pupation rate, or eclosion rate of C. anachoreta fed with leaves of transgenic and non-transgenic poplars. Furthermore, the arthropod communities in the Bt poplar and CK field stands were similar, as indicated by four diversity indices (Berge-Parker index, Shannon-Wiener indices, evenness index, and Simpson’s inverted index) and the Bray-Curtis index. Therefore, the Bt-Cry3A poplar decreased damage by the target pest (P. versicolora), had no effects on a non-target pest (C. anachoreta), and generally did not have any significant negative effect on the poplar arthropod community.     

Influence of herbicide tolerant soybean production systems on insect pest populations and pest-induced crop damage

Conventional soybean weed management and transgenic herbicide-tolerant management were examined to assess their effects on soybean insect pest populations in south Georgia in 1997 and 1998. Soybean variety had very little impact on the insect species observed, except that maturity group effects were observed for stink bug, primarily Nezara viridula (L.), population densities on some sampling dates. Stink bugs were more abundant on the early maturing varieties in mid-season. Velvetbean caterpillar, Anticarsia gemmatalis Hübner, potato leafhopper, Empoasca fabae (Harris), and grasshoppers Melanoplus spp. were more numerous on either conventional or herbicide-tolerant varieties on certain dates, although these differences were not consistent throughout the season. Soybean looper, Pseudoplusia includens (Walker), threecornered alfalfa hopper, Spissistilus festinus (Say), and whitefringed beetles, Graphognathus spp , demonstrated no varietal preference in this study. Few weed treatment differences were observed, but if present on certain sampling dates, then pest numbers were higher in plots where weeds were reduced (either postemergence herbicides or preplant herbicide plus postemergence herbicide). The exception to this weed treatment effect was grasshoppers, which were more numerous in weedy plots when differences were present. In post emergence herbicide plots, there were no differences in insect pest densities between the conventional herbicides (e.g., Classic, Select, Cobra, and Storm) compared with specific gene-inserted herbicide-tolerant materials (i.e., Roundup and Liberty). Defoliation, primarily by velvetbean caterpillar, was different between soybean varieties at some test sites but not different between herbicide treatments. We did not observe differences in seasonal abundance of arthropod pests between conventional and transgenic herbicide-tolerant soybean.