Effects of transgenic Bt cotton on overwintering characteristics and survival of Helicoverpa armigera

The effects of transgenic Bt cotton on the overwintering generation of the cotton bollworm, Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae), are unknown. We hypothesized that a Bt cotton diet may adversely affect fitness of this generation and examined fresh weight, lipids, glycogens, low-molecular-weight sugars and SCPs (supercooling points) of pupae, as well as survival of larvae, diapausing pupae and adult emergence in comparison with controls. Field and laboratory experiments showed that larvae fed on Bt cotton had a decreased pupation rate, and fewer entered diapause and emerged as adults compared with larvae fed non-Bt cotton. Furthermore, larvae fed Bt cotton had reduced pupal weight, glycogen content and trehalose levels both in diapausing and in non-diapausing pupae, and only diapausing pupae had an increased SCP compared to controls. The SCPs of diapausing pupae reared on Bt cotton were significantly higher than those reared on non-Bt cotton. The trehalose levels of diapausing pupae reared on Bt cotton were significantly lower than those of larvae reared on non-Bt cotton. Thus, these results suggest that a Bt cotton diet weakens the preparedness of cotton bollworm for overwintering and reduces survival of the overwintering generation, which will in turn reduce the density of the first generation in the following year. Effects of transgenic Bt cotton on the overwintering generation of cotton bollworm appear to have significantly contributed to the suppression of cotton bollworm observed throughout northern China in the past decade.     

棉铃虫老熟幼虫有效越冬虫量的分析

通过从棉田和玉米田采回的第 4代老熟幼虫的化蛹率和羽化率观察 ,发现棉田和玉米田的老熟幼虫化蛹率分别为 65%～ 83 0 5%和 55%～ 80 % ,其化蛹后的羽化率分别为 1 0 %～ 87%和 1 3 %～77% ,而且 2种寄主作物间无显著差异。由此进一步分析了棉田和玉米田老熟幼虫的有效越冬虫率和有效越冬虫量 ,作者认为 8月 3 1日至 9月 1 0日是棉铃虫老熟幼虫有效越冬虫量的主要来源期 ,且棉田显著高于玉米田 ,构成了第 2年棉铃虫种群发生基础。     

Consumptive and non‐consumptive effects of wolf spiders on cotton bollworms

Larvae of the cotton bollworm, Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae) that survive on genetically modified Bt cotton (Gossypium hirsutum L., Malvaceae) contribute to the risk of widespread resistance to Bt toxins. Current resistance management techniques include pupae busting, which involves deep tilling of the soil to kill overwintering pupae. Unfortunately, pupae busting runs counter to soil and water conserving techniques, such as minimum tillage. This problem could be relieved with biological control methods, whereby predators attack either larvae going to ground to pupate or moths emerging from the ground. We found that the wolf spider Tasmanicosa leuckartii (Thorell) (Araneae: Lycosidae), a common inhabitant of Australian cotton agroecosystems, is an effective predator of H. armigera, attacking and killing most larvae (66%) and emerging moths (77%) in simple laboratory arenas. Tasmanicosa leuckartii also reduced the number of emerging moths by 66% on average in more structurally complex glasshouse arenas. Males, females, and late‐instar juveniles of T. leuckartii were similarly effective. Tasmanicosa leuckartii also imposed non‐consumptive effects on H. armigera, as when a spider was present larvae in the laboratory areas spent less time on the cotton boll and more time on the soil and more mass was lost from the cotton boll. Increased loss of boll mass likely reflects changes in H. armigera foraging behavior induced by the presence of spiders (indirect non‐consumptive effects). Helicoverpa armigera spent more time as pupae when the spider was present in simple laboratory arenas, but not in more complex glasshouse enclosures. Overall, results indicate that T. leuckartii spiders can be effective predators of H. armigera late instars and moths but also suggest that, under some conditions, the presence of spiders could increase the damage to individual cotton bolls.     

Determining the major Bt refuge crops for cotton bollworm in North China

Evaluation of the effectiveness of refuge strategies involved in cotton bollworm Bt resistance management would be aided by technologies that allow monitoring and quantification of key factors that affect the process under field conditions. We hypothesized that characterization of stable carbon and nitrogen isotopes in adult bollworm, Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae) moths may aid in determining the larval host that they developed upon. We found moths reared from larvae fed on peanut, soybean or cotton, respectively, could be differentiated using isotopic analyses that also corresponded to their respective larval host origins. These techniques were then used to classify feral second‐generation bollworm moths caught in Bt cotton (Gossypium hirsutum) fields into different populations based on their isotopic signatures. In 2006–2007 feral moths captured in Bt cotton fields predominantly correlated with the peanut (Arachis hypogea) having served as their larval host, indicating this is the most important refuge crop for Bt‐susceptible bollworm individuals (providing 58%?64% individuals) during independent moth peaks for the second generation in North China. The remaining feral moths correlated with soybean (Glycine max) (0?10%); other C₃ plant (20%?22%) and non‐C₃ plant (12%?14%) host types also provided some Bt‐sensitive moths. Field observations showed that peanut constitutes the primary refuge crop contributing to sustaining Bt‐susceptible moths dispersing into cotton in North China. These results suggest that peanut may be a more effective refuge to sustain Bt‐susceptible bollworm individuals and reduce the risk of development of a Bt‐resistant biotype.     

Effects of elevated CO2 and transgenic Bt cotton on plant chemistry, performance, and feeding of an insect herbivore, the cotton bollworm

Effects of elevated atmospheric CO₂ (double‐ambient CO₂) on the growth and metabolism of cotton bollworm, Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae), fed on transgenic Bacillus thuringiensis (Berliner) (Bt) cotton [Cry1A(c)], grown in open‐top chambers, were studied. Two levels of CO₂ (ambient and double‐ambient) and two cotton cultivars (non‐transgenic Simian‐3 and transgenic GK‐12) were deployed in a completely randomized design with four treatment combinations, and the cotton bollworm was reared on each treatment simultaneously. Plants of both cotton cultivars had lower nitrogen and higher total non‐structural carbohydrates (TNC), TNC:Nitrogen ratio, condensed tannin, and gossypol under elevated CO₂. Elevated CO₂ further resulted in a significant decrease in Bt toxin level in GK‐12. The changes in chemical components in the host plants due to increased CO₂ significantly affected the growth parameters of H. armigera. Both transgenic Bt cotton and elevated CO₂ resulted in a reduced body mass, lower fecundity, decreased relative growth rate (RGR), and decreased mean relative growth rate in the bollworms. Larval life‐span was significantly longer for H. armigera fed transgenic Bt cotton. Significantly reduced larval, pupal, and adult moth weights were observed in the bollworms fed elevated CO₂‐grown transgenic Bt cotton compared with those of bollworms reared on non‐transgenic cotton, regardless of the CO₂ level. The efficiency of conversion of ingested food and of digested food of the bollworm were significantly reduced when fed transgenic Bt cotton, but there was no significant CO₂ or CO₂× cotton cultivar interaction. Approximate digestibility of larvae reared on transgenic cotton grown in elevated CO₂ was higher compared to that of larvae fed non‐transgenic cotton grown at ambient CO₂. The damage inflicted by cotton bollworm on cotton, regardless of the presence or absence of insecticidal genes, is predicted to be more serious under elevated CO₂ conditions because of individual compensatory feeding on host plants caused by nitrogen deficiency.     

食物对棉铃虫生长发育及繁殖的影响

用棉花、花生、玉米及人工饲料作为食料,模拟幼虫田间取食习性,同时为雌蛾设立补充和无补充营养两个处理,研究了食物对棉铃虫 Helicoverpa armigera (Hübner) 生长发育及繁殖的影响。4种食料组幼虫历期之间有显著差异;雌、雄蛹重花生组显著小于其余三组。雌蛾腹部干重及其脂肪百分含量与雌蛹体重的排列顺序一样,雌蛾腹部干重人工饲料组显著大于棉花组和花生组。雌蛾寿命和繁殖受幼虫食料和成虫食物的双重影响。喂10%蜂蜜时,雌蛾寿命、交配率和产卵量在四个幼虫食料组之间没有显著差异。但喂以清水时,花生组雌蛾均未交配,寿命和产卵量显著小于其余三组。从同种幼虫食料来看,除人工饲料组外,其余3组雌蛾喂清水时的产卵量和寿命均比喂10%蜂蜜溶液时的显著下降。基于这些结果,作者认为棉花、玉米比花生更适合于棉铃虫的生长发育和繁殖。在田间自然栽培状态下,不同食料植物的糖分含量对棉铃虫生长发育和繁殖影响较大,含氮量的变化影响小。     

寄主植物对棉铃虫越冬蛹抗寒能力的影响

通过对滞育蛹过冷却点的测定 ,初步明确寄主对棉铃虫Helicoverpaarmigera的越冬抗寒性有影响 ,幼虫取食棉花时产生的滞育蛹的过冷却点低于取食玉米的滞育蛹的过冷却点 ,即前者的抗寒能力高于后者 ;但用Bt棉喂养后的棉铃虫滞育蛹抗寒能力下降     

Spring phenology of cotton bollworm affects wheat yield

Climate change has changed numerous species phenologies. Understanding the asynchronous responses between pest insects and host plants to climate change is helpful in improving integrated pest management. It is necessary to use long‐term data to analyze the effects of climate change on cotton bollworm and wheat anthesis. Data for cotton bollworm, wheat yield, and wheat anthesis collected since 1990 were analyzed using linear regression and partial least‐squares regression, as well as the Mann–Kendall test. The results showed that warmer temperatures in the spring advanced the phenologies of cotton bollworm and wheat anthesis, but the phenology changes in overwintering cotton bollworm were faster than those in wheat anthesis, and the eclosion period of overwintering was prolonged, resulting in an increase in overwintering adult abundance. This might lead to more first‐generation larvae and subsequent wheat damage. An early or late first‐appearance date significantly affected the eclosion days. The abrupt changes of phenologies in cotton bollworm, wheat anthesis, and climate were asynchronous, but the abrupt phenology changes occurred after or around the climate abrupt change, especially after or around the abrupt changes of temperature in March and April. The expansion of asynchronous responses in the change rate of wheat anthesis and overwintering cotton bollworm would likely decrease wheat yield due to climate warming in the future. Accumulated temperature was the major affecting factor on the first eclosion date (t₁), adult abundance, and eclosion days. Temperatures in March and April and precipitation in the winter mainly affected the prepeak date (t₂), peak date (t₃), and postpeak date (t₄), respectively, and these factors indirectly affected wheat yield. Thus, the change in the spring phenology of the cotton bollworm and wheat anthesis, and hence wheat yield, was affected by climate warming.     

转基因抗虫棉种植面积变化对花生田棉铃虫种群影响

【目的】棉铃虫Helicoverpa armigera(Hübner)是花生田主要害虫之一。转基因抗虫棉全面推广后,棉铃虫种群(包括棉田、花生田、玉米田)得到有效控制。近年,随着转基因抗虫棉种植面积逐年下降,花生田棉铃虫种群呈现逐年上升趋势。【方法】本文通过调查山东省花生主产区(非棉区)龙口、招远、莱阳、文登四个县级市花生田棉铃虫成虫、卵量、幼虫量等的发生情况,分析了棉铃虫发生面积及种群数量15年(2000—2014年)的变化规律,并重点分析了主要影响因素。【结果】结果表明:花生棉铃虫发生面积受棉花种植面积影响较大,二者呈显著负相关性;花生田棉铃虫累计诱蛾量总体呈下降趋势,但与棉花种植面积相关性不显著;棉铃虫卵量、虫量与抗虫棉种植面积呈显著负相关性。【结论】所以,转基因抗虫棉种植面积减少是导致花生田棉铃虫种群数量上升的主要因素。另外,近年玉米田棉铃虫发生面积也呈逐年上升趋势,与抗虫棉种植面积呈显著负相关。所以,随转基因抗虫棉种植面积的下降,若不采取有效措施,棉铃虫种群可能会出现大发生趋势。     

Transgenic cotton expressing synthesized scorpion insect toxin AaHIT gene confers enhanced resistance to cotton bollworm (Heliothis armigera) larvae

A synthetic scorpion Hector Insect Toxin (AaHIT) gene, under the control of a CaMV35S promoter, was cloned into cotton via Agrobacterium tumefaciens-mediated transformation. Southern blot analyses indicated that integration of the transgene varied from one to more than three estimated copies per genome; seven homozygous transgenic lines with one copy of the T-DNA insert were then selected by PCR and Southern blot analysis. AaHIT expression was from 0.02 to 0.43% of total soluble protein determined by western blot. These homozygous transgenic lines killed larvae of cotton bollworm (Heliothis armigera) by 44–98%. The AaHIT gene could used therefore an alternative to Bt toxin and proteinase inhibitor genes for producing transgenic cotton crops with effective control of bollworm.     

不同食料植物对棉铃虫生长发育和繁殖的影响

报道了棉花、烟草、番茄和辣椒4种植物对棉铃虫Helicoverpa armigera生长发育和繁殖的影响。棉铃虫成虫喜欢在番茄上产卵,在辣椒上的着卵量最少。初孵幼虫喜选食嫩棉叶,选食辣椒嫩叶的虫数最少。4组幼虫取食嫩叶时的平均相对生长速率都有显著差异,顺序为棉叶组>烟叶组>番茄叶组>辣椒叶组。幼虫存活率以取食棉花时最高,取食番茄时最低。棉花组成虫的产卵量最高,烟草组的产卵量最低。取食棉花的棉铃虫种群增长的速度约为取食番茄时的14倍。6龄幼虫能有效利用和转化棉铃、烟草蒴果、辣椒果实,而对番茄果实的利用和转化效率较低。棉铃虫可分别以这4种植物的不同器官为食完成世代循环。其中,棉花是最适宜的寄主,辣椒和番茄是较不适宜的寄主。     

Regulation of the seasonal population patterns of <Emphasis Type="Italic">Helicoverpa armigera</Emphasis> moths by <Emphasis Type="Italic">Bt</Emphasis> cotton planting

Transgenic cotton expressing the Bacillus thuringiensis (Bt) Cry1Ac toxin has been commercially cultivated in China since 1997, and by 2000 Bt cotton had almost completely replaced non-transgenic cotton cultivars. To evaluate the impact of Bt cotton planting on the seasonal population patterns of cotton bollworm, Helicoverpa armigera, the dynamics of H. armigera moths were monitored with light traps from four locations (Xiajin, Linqing and Dingtao of Shandong Province; Guantao of Hebei Province) in high Bt density region and five locations (Anci and Xinji of Hebei Province; Dancheng and Fengqiu of Henan Province; Gaomi of Shandong Province) in low Bt density region from 1996 to 2008. A negative correlation was found between moth densities of H. armigera and the planting years of Bt cotton in both high and low Bt density areas. These data indicate that the moth population density of H. armigera was reduced with the introduction of Bt cotton in northern China. Three generations of moths occurred between early June and late September in the cotton regions. Interestingly, second-generation moths decreased and seemed to vanish in recent years in high Bt density region, but this tendency was not found in low Bt density region. The data suggest that the planting of Bt cotton in high Bt density region was effective in controlling the population density of second-generation moths. Furthermore, the seasonal change of moth patterns associated with Bt cotton planting may regulate the regional occurrence and population development of this migratory insect.     

Effect of water-deficit stress on cotton plants expressing the Bacillus thuringiensis toxin

Bacillus thuringiensis (Bt) crops require a high dosage of Bt toxin to delay development of insect resistance, in particular, when the refuge strategy is applied. This strategy is threatened by plant developmental and environmental factors that might reduce Bt toxin concentration and Bt efficacy in Bt crops. Growth of Bt (Cry1Ac) cotton under prolonged, moderate water deficit as a single stress factor was evaluated. Bt cotton plants were analysed for physiological performance, Bt toxin concentration and Bt efficacy. For performance analysis, leaf and total plant dry weight and leaf area were measured. Bt toxin concentration was determined by an immuno‐assay. Effects of Bt toxin on growth and mortality of African cotton bollworm, Helicoverpa armigera, larvae were measured in different plant organs. Leaves from young plants exposed for 30 days to moderate water deficit had both higher Bt toxin concentrations and were more effective against larvae than leaves, flowers or bolls from mature flowering plants exposed to 60 days of moderate water deficit. Although growth of Bt cotton plants under moderate water‐deficit conditions decreased Bt concentrations in leaves, flowers and bolls, this had no effect on efficacy against first‐instar cotton bollworm larvae. No significant evidence was found that moderate water deficit, as a single stress factor, decreases Bt efficacy in Bt cotton.     

The emergence and control of overwintering Helicoverpa armigera pupae in southern New South Wales

Abstract  The extent and timing of the spring emergence of Helicoverpa armigera moths from overwintering pupae was measured in southern New South Wales (NSW). Survival was comparable to that in northern NSW, suggesting that the colder conditions did not significantly reduce the survival of overwintering pupae. Most adults emerged from mid-October to mid-November, approximately 2 weeks later than reported in northern NSW. The pattern of emergence is similar to that predicted by the HElicoverpa Armigera and Punctigera Simulation (HEAPS) model, although it tended to be earlier than predicted. Simulation of the pattern of emergence from 1990 to 2001 predicted a range of approximately 4 weeks in the date of emergence. This suggests that moths will not emerge in this part of southern NSW before October. The impact of locally used cultivation techniques on the survival of overwintering pupae supported previous findings highlighting the need for either plant line or full cultivation to ensure adequate control of overwintering pupae. Neither direct drilling nor shallow cultivation (Lillistons) provided consistently reliable control. Practical management of overwintering pupae in the region requires adequate cultivation before October     

Effects of elevated CO2 on the foraging behavior of cotton bollworm, Helicoverpa armigera

Effects of elevated CO2 on the foraging behavior of cotton bollworm Helicoverpa arrnigera Hübner reared on milky grains of spring wheat grown in ambient, 550μL/L and 750μL/L CO2 concentration atmospheres in open-top chambers （OTC） were studied. The results indicated that： （i） elevated CO2 significantly affected both the type and amount of food eaten by H.arrnigera reared on milky grains of ambient CO2-grown wheat were significant higher than those for bollworm larvae reared on wheat grains grown in 550 and 750μL/L CO2 atmospheres; （ii） when bollworm larvae were reared on mixed milky grains from different CO2-grown wheat （food-choice condition）, larval duration increased significantly-pupal weight, adult longevity, and fecundity decreased significantly, comparing with those reared on milky grains of ambient CO2-grown wheat, 550μL/L CO2-grown wheat and 750μL/L CO2-grown wheat respectively; （iii） significant decreases in the contents of fructose and gross protein （GP） and significant increases in the contents of glucose, amylose, total saccharides （TSC）, TSC： GP ratio, free amino acids and soluble protein in the wheat grains with CO2 rising; （iv） and selected-foraging amount/food-choice index of cotton bollworm H.armigera were significantly positive correlated with the contents of fructose and GP of wheat grains, but they had significantly negative relationships with the contents of glucose, amylose, TSC and TSC： GP ratio of wheat grains.     

Overwintering cost associated with resistance to transgenic cotton in the pink bollworm (Lepidoptera: Gelechiidae)

Fitness costs associated with resistance to transgenic crops producing toxins from Bacillus thuringiensis (Bt) may have important effects on the evolution of resistance. We investigated overwintering costs in pink bollworm, Pectinophora gosypiella (Saunders), strains with different degrees of resistance to Bt cotton. Frequency of resistant individuals in a strain was not associated with induction of diapause or emergence from diapause in early winter. Emergence from diapause in the spring was 71% lower in three highly resistant strains than in two heterogeneous strains from which the resistant strains were derived. This underestimates the overwintering cost because the frequency of the resistance allele was relatively high in the heterogeneous strains. Emergence in the spring in hybrid progeny from crosses between the resistant and heterogeneous strains was greater than in resistant strains but did not differ from susceptible strains, showing that the overwintering cost was recessive to some extent.     

Overwintering of Heliothis virescens (F.) and Helicoverpa zea (Boddie) (Lepidoptera: Noctuidae) in cotton fields of northeast Mississippi

Following the 1995-2001 crop seasons, population densities of pupae of tobacco budworm, Heliothis virescens (F.), and corn earworm, Helicoverpa zea (Boddie), overwintering in cotton fields, Gossypium hirsutum L., in Monroe County, MS, were estimated by digging a total of 43,542 m-row. Densities of pupae varied greatly among years with the highest densities occurring in years with low rainfall in the late summer and early fall. The sex ratio of pupae was variable and significantly male-biased in some years. The total area-wide, tobacco budworm population emerging from all overwintering sites was estimated from catches in pheromone traps whose absolute efficiency is known. After the introduction of Bacillus thuringiensis Berliner (Bt)-transgenic cotton in 1996 but before a several-fold increase in use of herbicide resistant (HR)-transgenic cotton cultivars in 2001, local cotton fields accounted for <2% of the total overwintered tobacco budworm population. In the pretransgenic cotton production era, it is estimated cotton fields typically accounted for <10% of the overwintered tobacco budworm population. Driving surveys of the tillage status of cotton fields and pheromone trapping to determine the timing of adult emergence in the spring indicate that--until the 2000 crop season--postseason tillage destroyed most tobacco budworm and corn earworm pupae overwintering in cotton fields. Adoption of HR-transgenic cultivars has quintupled cotton field area planted no-till, but the contribution of cotton fields to overwintered tobacco budworm populations has remained low. Preemptive tillage of cotton fields to kill overwintering tobacco budworm pupae would not appreciably suppress in-season population densities of this pest. However, the absence of such tillage might increase the rate at which the tobacco budworm develops resistance to insecticides and counteradaptation to antibiotic host plant resistance traits including the Bt-transgenic trait.     

Effects of the Cry1Ac toxin of Bacillus thuringiensis on Microplitis mediator, a parasitoid of the cotton bollworm, Helicoverpa armigera

Interactions between the cotton bollworm, Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae), its larval parasitoid Microplitis mediator (Haliday) (Hymenoptera: Braconidae), and the Cry1Ac toxin of Bacillus thuringiensis Berliner were evaluated under laboratory conditions. The growth of H. armigera larvae was delayed and its pupal rate and pupal weight decreased when they were fed on a diet containing Cry1Ac toxin. Due to the lowered growth rate of the host larvae, the time available for parasitization of H. armigera by M. mediator increased when the host larvae were reared on a diet containing Cry1Ac toxin at concentrations of 0.5, 1, 2, and 4 µg g^?1. The longevity of female and male parasitoids was not significantly affected when newly emerging wasps fed on honey solutions containing three different concentrations of Cry1Ac toxin (125, 250, and 500 µg ml^?1). When female parasitoids were fed on honey solutions containing Cry1Ac, their offsprings’ egg and larval development period, pupal weight, length of pupation, adult weight, and adult longevity did not change significantly in most of the treatments compared with controls. When the female parasitoids parasitized host larvae that had been fed on a diet containing 0.5, 1, 2, 4, and 8 µg g^?1 Cry1Ac toxin, their offsprings’ eggs and larvae were significantly delayed. Their pupal weight, adult weight, and adult longevity were also significantly less than controls.     

Next‐generation transgenic cotton: pyramiding RNAi and Bt counters insect resistance

Transgenic crops producing insecticidal proteins from the bacterium Bacillus thuringiensis (Bt) are extensively cultivated worldwide. To counter rapidly increasing pest resistance to crops that produce single Bt toxins, transgenic plant ‘pyramids’ producing two or more Bt toxins that kill the same pest have been widely adopted. However, cross‐resistance and antagonism between Bt toxins limit the sustainability of this approach. Here we describe development and testing of the first pyramids of cotton combining protection from a Bt toxin and RNA interference (RNAi). We developed two types of transgenic cotton plants producing double‐stranded RNA (dsRNA) from the global lepidopteran pest Helicoverpa armigera designed to interfere with its metabolism of juvenile hormone (JH). We focused on suppression of JH acid methyltransferase (JHAMT), which is crucial for JH synthesis, and JH‐binding protein (JHBP), which transports JH to organs. In 2015 and 2016, we tested larvae from a Bt‐resistant strain and a related susceptible strain of H. armigera on seven types of cotton: two controls, Bt cotton, two types of RNAi cotton (targeting JHAMT or JHBP) and two pyramids (Bt cotton plus each type of RNAi). Both types of RNAi cotton were effective against Bt‐resistant insects. Bt cotton and RNAi acted independently against the susceptible strain. In computer simulations of conditions in northern China, where millions of farmers grow Bt cotton as well as abundant non‐transgenic host plants of H. armigera, pyramided cotton combining a Bt toxin and RNAi substantially delayed resistance relative to using Bt cotton alone.     

紫茎泽兰乙醇提取物对棉铃虫生长发育和繁殖力的影响

采用室内生物测定法研究了紫茎泽兰Eupatorium adenophorum Spreng乙醇提取物对棉铃虫Helicoverpa armigera (Hübner)生长发育和繁殖力的影响。结果表明,当给棉铃虫幼虫饲喂含紫茎泽兰提取物浓度分别为0.088、0.44、2.2和11 g/kg的饲料时,棉铃虫的死亡率显著高于对照,而羽化率和蛹重均显著低于对照（P≤0.05）。在棉铃虫成虫产卵实验中,0.08、0.4和2 g/L紫茎泽兰提取物对产卵有一定引诱作用,而10 g/L则对产卵有驱避作用。取食浓度分别为0.08、0.4、2和10 g/L紫茎泽兰提取物的棉铃虫卵孵化率降低。表明取食紫茎泽兰提取物对棉铃虫的生长发育和繁殖有明显不利影响。