Effect of cotton cultivar on development and reproduction of Aphis gossypii (Homoptera: Aphididae) and its predator Propylaea japonica (Coleoptera: Coccinellidae)

The effects of three cotton cultivars with low ('ZMZ13'), medium ('HZ401'), and high ('M9101') gossypol contents on the development, reproduction, and survival of Aphis gossypii Glover and its predator Propylaea japonica (Thunberg) were investigated. Developmental duration and immature survivorship did not vary between aphids on the three cultivars, whereas A. gossypii feeding on M9101 (high gossypol cultivar) displayed significantly shorter adult longevity and lower fecundity than aphids fed on 'ZMS13' and 'HZ401'. Free fatty acid content in cotton aphids reared on 'M9101' was greater than in those reared on 'HZ401' and 'ZMS13'. No significant differences in survival and lifetime fecundity of P. japonica were observed between P. japonica fed cotton aphids reared on the three different cultivars. P. japonica fed aphids from 'M9101' showed a significantly shorter developmental period and greater adult weight than those fed aphids from the other two cultivars. The decreased larval developmental duration and increased adult weight of P. japonica fed cotton aphids reared on the high gossypol-containing cultivar might have been caused by the high fatty acid content of the prey aphids. Our results indicate that high gossypol in host cotton had an antibiotic effect on A. gossypii and showed a positive effect on growth and development of P. japonica at the third trophic level. This suggests compatibility between one form of host plant resistance and biological control by predators. The allelochemical contents should be taken into account in integrated pest management for their effects on both herbivores and entomophagous insects.     

Effects of neem-based insecticides on beet armyworm （Lepidoptera： Noctuidae）

Abstract Three commercial neem [ Azadirachta indica A. Juss (Meliaceae)]-based insecticides, Agroneem, Ecozin, and Neemix, and a non-commercial neem leaf powder, were evaluated for oviposition deterrence, antifeedant effect on larvae, and toxicity to eggs and larvae of the beet armyworm, Spodoptera exigua (Hübner) (Lepidoptera: Noctuidae), on cotton leaves in the laboratory. Oviposition deterrence in no-choice, and two- and fivechoice assays, was observed for the neem-based insecticide treatments when compared with a non-treated control. Neem-based insecticides also deterred feeding by beet armyworm larvae. Direct contact with neem-based insecticides decreased the survival of beet armyworm eggs. Survival of beet armyworm larvae fed for 7 days on leaves treated with neembased insecticides was reduced to 27, 33, 60, and 61% for neem leaf powder, Ecozin, Agroneem, and Neemix, respectively. Possibilities for adoption of neem-based insecticides in commercial cotton for beet armyworm control are discussed.     

不同方式诱导植物抗性对甜菜夜蛾幼虫及其寄生蜂斑痣悬茧蜂发育表现的影响

【目的】明确诱导植物抗性对植食性昆虫甜菜夜蛾 Spodoptera exigua (Hübner) 及内寄生蜂斑痣悬茧蜂 Meteorus pulchricornis (Wesmael) 生长发育的影响。【方法】采用取食损伤、机械损伤及外源喷施3种浓度 (0.01, 0.1和1 mmol/L) 茉莉酸甲酯 (MeJA) 3种方式来诱导菜薹抗性,观察甜菜夜蛾初孵幼虫及其寄生蜂斑痣悬茧蜂的发育表现。【结果】取食取食损伤和茉莉酸甲酯处理的菜薹后,甜菜夜蛾幼虫存活率显著降低,茉莉酸甲酯浓度与幼虫存活呈负相关; 取食0.1 mmol/L MeJA处理的菜薹后,甜菜夜蛾幼虫体重显著低于清水对照。甜菜夜蛾取食取食损伤和0.1 mmol/L MeJA处理的菜薹,其寄生蜂斑痣悬茧蜂幼虫的死亡率显著增加,同时结茧率显著降低;0.1 mmol/L MeJA处理的菜薹使成蜂体重显著低于对照。不同处理间斑痣悬茧蜂的卵巢发育无明显差异,卵巢由8~10根卵巢管组成,羽化24 h后成熟卵数量为7~10个,成熟卵的长度和宽度分别为350和78 μm。【结论】结果说明,取食损伤和茉莉酸甲酯处理诱导的菜薹反应会影响甜菜夜蛾的存活和大小,进而抑制斑痣悬茧蜂生长。     

Host plant resistance in romaine lettuce affects feeding behavior and biology of Trichoplusia ni and Spodoptera exigua (Lepidoptera: Noctuidae)

Lettuce quality and yield can be reduced by feeding of several lepidopterous pests, particularly cabbage looper, Trichoplusia ni (Hübner), and beet armyworm, Spodoptera exigua (Hübner) (Lepidoptera: Noctuidae). Host plant resistance to these insects is an environmentally sound adjunct to conventional chemical control. In this study we compared the survival, development, and feeding behavior of cabbage looper and beet armyworm on two romaine lettuce cultivars, resistant 'Valmaine' and susceptible 'Tall Guzmaine'. Larval mortality of both species was significantly higher on resistant Valmaine than on susceptible Tall Guzmaine. The average weight per larva after feeding for 1 wk on Tall Guzmaine plants was 6 times (beet armyworm) and 2 times (cabbage looper) greater than that of larvae feeding on Valmaine plants. Significant reduction in larval growth on Valmaine compared with that on Tall Guzmaine resulted in a 5.9- (beet armyworm) and 2.6-d (cabbage looper) increase in larval duration and almost a 1-d increase in pupal duration. Average pupal and adult weights and successful pupation of cabbage looper and beet armyworm were reduced on Valmaine compared with Tall Guzmaine. The sex ratio of progeny did not deviate from 1:1 when larvae were reared on either Valmaine or Tall Guzmaine. The fecundity of cabbage looper and beet armyworm adults that developed from larvae reared on Valmaine was about one-third that of adults from Tall Guzmaine, but adult longevity did not significantly differ on the two lettuce cultivars. The two insect species showed different feeding preferences for leaves of different age groups on Valmaine and Tall Guzmaine. Cabbage loopers cut narrow trenches on the leaf before actual feeding to block the flow of latex to the intended site of feeding. In contrast, beet armyworms did not trench. The different feeding behavior of the two species on Valmaine may explain the superior performance of cabbage looper compared with beet armyworm.     

Effects of elevated CO2 and plant genotype on interactions among cotton,aphids and parasitoids

Abstract Effects of CO₂ level (ambient vs. elevated) on the interactions among three cotton (Gossypium hirsutum) genotypes, the cotton aphid (Aphis gossypii Glover), and its hymenoptera parasitoid (Lysiphlebia japonica Ashrnead) were quantified. It was hypothesized that aphid‐parasitoid interactions in crop systems may be altered by elevated CO₂, and that the degree of change is influenced by plant genotype. The cotton genotypes had high (M9101), medium (HZ401) and low (ZMS13) gossypol contents, and the response to elevated CO₂ was genotype‐specific. Elevated CO₂ increased the ratio of total non‐structural carbohydrates to nitrogen (TNC: N) in the high‐gossypol genotype and the medium‐gossypol genotype. For all three genotypes, elevated CO₂ had no effect on concentrations of gossypol and condensed tannins. A. gossypii fitness declined when aphids were reared on the high‐gossypol genotype versus the low‐gossypol genotype under elevated CO₂. Furthermore, elevated CO₂ decreased the developmental time of L. japonica associated with the high‐gossypol genotype and the low‐gossypol genotype, but did not affect parasitism or emergence rates. Our study suggests that the abundance of A. gossypii on cotton will not be directly affected by increases in atmospheric CO₂. We speculate that A. gossypii may diminish in pest status in elevated CO₂ and high‐gossypol genotype environments because of reduced fitness to the high‐gossypol genotype and shorter developmental time of L. japonica.     

幼虫食物对甜菜夜蛾生长发育、繁殖及飞行的影响

报道了人工饲料、圆白菜和玉米苗三种食物对甜菜夜蛾Spodoptera exigua发育历期、蛹重以及成虫产卵和飞行能力的影响。幼虫取食人工饲料时发育历期最短,蛹最重(138 mg),产卵量最高(643粒);在12 h的吊飞测试中,成虫飞行距离最远(25.5 km),飞行时间最长(6.2 h),飞行超过10 km的个体占67.9%,超过5 h的占60.7%。幼虫取食玉米苗时发育历期最长,蛹最轻(52 mg),产卵量最低(416粒),成虫仅能飞行3.3 km,1.7 h,飞行超过10 km或5 h的个体均仅占4.2%,各项指标均显著低于人工饲料组。幼虫取食圆白菜时各项指标与人工饲料组基本相似(幼虫历期和蛹重除外),而显著优于玉米苗组(幼虫历期除外)。这些结果表明,幼虫食物对甜菜夜蛾的生长发育、产卵及飞行能力均有显著的影响,因而是影响其个体发育、种群增长及种群动态的重要因素之一。同时,由于取食本人工饲料的各项指标均优于其它两种食料植物,因而可作为饲养甜菜夜蛾的实用饲料。     

甜菜夜蛾群体繁殖及其对杀虫剂毒力敏感性测定

用黄豆粉、麦胚粉、酵母粉为主要营养成份研制成人工饲料,实现了甜菜夜蛾大量饲养及群体繁殖,与自然饲料相比,人工饲料饲养甜菜夜蛾幼虫存活与成虫产卵量明显增加,室内用浸渍法测定11种杀虫剂对甜菜夜蛾2龄幼虫的毒力,结果表明,田间甜菜夜蛾种群对除尽,米满,菜喜最敏感,其次是对抑太保,卡死克,毒丝本,高效灭百可,快灵,对锐劲特,氯氰菊酯,乙酰甲胺磷的毒力均已高度不敏感。     

寄主植物对甜菜夜蛾的发育和繁殖及体内酯酶活性的影响

在恒温(2 8±1 )℃条件下考察了葱、苋菜、豇豆、蕹菜、菜心5种寄主植物对甜菜夜蛾SpodopteraexiguaH櫣ｂｎｅｒ的营养效应及体内羧酸酯酶、乙?铛ッ富钚缘挠跋?,结果表明,不同寄主植物对甜菜夜蛾幼虫和蛹的发育历期、存活率、蛹重、雌成虫产卵量等有显著影响,其中对雌成虫产卵量的影响最大。雌成虫产卵量最高为取食菜心的处理,其次是取食葱的处理。寄主植物对甜菜夜蛾体内羧酸酯酶、乙酰胆碱酯酶活性也有显著影响,但这些酶的活性与发育历期、存活率、产卵量无明显相关性。在进行预测预报、田间防治时应充分考虑寄主植物对甜菜夜蛾发育历期、产卵量、解毒酶活性的影响。     

甜菜夜蛾不同龄期幼虫对药剂的敏感性及其与酶活力的关系

【目的】明确甜菜夜蛾Spodoptera exigua(Hübner)不同龄期幼虫对甲氨基阿维菌素苯甲酸盐和毒死蜱的敏感性及其与羧酸酯酶、多功能氧化酶、谷胱甘肽S-转移酶和乙酰胆碱酯酶活性的相关性。【方法】采用室内生物测定方法检测甜菜夜蛾不同龄期幼虫对药剂的敏感性,并检测了不同龄期幼虫体内羧酸酯酶、多功能氧化酶、谷胱甘肽S-转移酶和乙酰胆碱酯酶的活力。【结果】在所测定的5个龄期中,随龄期增加,敏感性逐渐降低,其中1~5龄幼虫对甲氨基阿维菌素苯甲酸盐的LC50分别为0.1010、0.3561、0.7568、1.4325和8.4390 mg/L,对毒死蜱的LC50分别为27.4632、46.8495、87.5222、129.3217和1 356.6770 mg/L。单头幼虫的羧酸酯酶、多功能氧化酶、谷胱甘肽S-转移酶和乙酰胆碱酯酶活力随虫龄的增加而提高,与龄期间对药剂的敏感性呈负相关(由于外源化合物摄入量减少,5龄单头幼虫的多功能氧化酶活力略有降低)。【结论】甜菜夜蛾不同龄期幼虫对药剂的敏感性存在非常明显的差异,在田间防治中,应选择对杀虫剂敏感性较高的低龄幼虫作为最佳防治时期。     

Indirect Chilling Injury of Spodoptera exigua in Response to Long-Term Exposure to Sublethal Low Temperature

We report indirect chilling injury, which is caused by the long-term exposure to the low temperature above freezing point, found in the beet armyworm, Spodoptera exigua. Short (minute or hour) exposure to 5°C was not lethal to all stages of S. exigua. However, several day-exposure to 5°C gave significant nonfreezing injuries such as low egg hatchability, retarded larval development, and low pupation rates. Even though the larvae did not develop at 5°C, they used up their major nutrient reserves significantly. The mechanism of the indirect chilling injury of the beet armyworm was discussed on the basis of the oxidative stress hypothesis.     

转Bt基因玉米对甜菜夜蛾幼虫存活和发育的影响

在室内测定了2种转Cry1Ab基因的Bt玉米MON810和Bt11不同组织对甜菜夜蛾 Spodoptera exigua （Hübner）初孵幼虫以及心叶对4龄幼虫存活和发育的影响,在田间比较了甜菜夜蛾幼虫取食Bt 和非Bt玉米雌穗的存活和为害情况。结果表明,转Cry1Ab基因的Bt玉米的不同组织对甜菜夜蛾初孵幼虫都具有明显的杀虫活性,取食Bt玉米心叶、苞叶、籽粒时甜菜夜蛾均在幼虫期死亡; 取食MON810和Bt11雄穗的初孵幼虫化蛹率分别为5.2%和2.1%,羽化率为2.1%和1.0%;取食MON810和Bt11花丝的初孵幼虫化蛹率分别为1.0%和2.1%,但不能羽化。4龄幼虫取食MON810玉米心叶的化蛹率与对照差异不显著,而取食Bt11的化蛹率与对照差异显著; 取食两种Bt玉米心叶的４龄幼虫化蛹后的雌、雄蛹重和羽化率与对照组差异显著,但蛹期和平均单雌产卵量差异不显著,虽然对照组羽化的成虫平均产卵量高于Bt玉米组。田间接种初孵幼虫10 天后的调查结果表明,在MON810和Bt11玉米花丝上幼虫存活率分别为1.3%和0.3%, 而对照组分别为12.9%和16.2%;MON810和Bt11玉米雌穗被害率分别为18.3%和5.0%,而对照组分别为93.3%和95.0%,均显著低于对照组。     

寄主植物对甜菜夜蛾三龄幼虫抗寒力的影响

寄主植物是影响昆虫抗寒性的主要因子之一。研究了不同温度下甜菜夜蛾Spodoptera exigua(Hübner)3龄幼虫取食小白菜、甘蓝、葱和菠菜后,对过冷却能力和体内冷冻保护剂的影响。结果表明,寄主植物对甜菜夜蛾3龄幼虫的过冷却能力有显著性影响,其中以取食甘蓝的幼虫过冷却点最低。温度和寄主植物对其过冷却点、结冰点和虫体含水量有明显的交互作用。寄主植物对其体内的海藻糖含量有显著性影响,而对甘油和糖原含量没有显著性影响。温度和寄主植物仅对海藻糖含量有显著的交互作用。随着温度的升高,取食不同寄主的幼虫体内海藻糖和糖原含量的变化趋势完全相反,认为海藻糖是由糖原转化而来。研究结果提示冬季合适的寄主植物有利于甜菜夜蛾低龄幼虫越冬。     

Effects of Host Cell Density on Cell Infection Level in Antheraea eucalypti (Lepidoptera: Saturniidae) Cell Cultures Persistently Infected with Nosema bombycis (Microsporida: Nosematidae)

ABSTRACT. Spores of Nosema bombycis Y9101, isolated from the beet armyworm, Spodoptera exigua , were primed with an alkaline solution and inoculated into Antheraea eucalypti cell cultures. Infected cells were subcultured every five days at three cell densities (2.5 × 10³, 5.0 × 10³, and 1.0 × 10⁴ cells/cm²). A difference was observed in the spread of N. bombycis Y9101 infection between low-density and higher-density cultures of host cells. The host cell density did not affect the productivity of secondary infective forms of the parasite. The principal factor determining the rate of microsporidian infection in vitro was the number of host cells existing within the reach of extruded short-coiled polar tubes from spores germinated intracellularly.     

Pb2+在甜菜夜蛾体内的积累及对种群的影响

重金属的污染及其治理是目前倍受关注的生态学问题之一.甜菜夜蛾是我国长江流域及以南地区蔬菜、棉花等作物上的主要害虫,近几年突发趋势明显.本文以甜菜夜蛾为靶标对象,设计5个浓度(0.3、1.2、4.8、19.2、76.8 mg · kg^-1)重金属Pb²⁺处理,探讨处理后甜菜夜蛾各虫态体内Pb²⁺的积累和排泄,并根据甜菜夜蛾各虫态的生长与存活情况,构建了该虫连续3个世代的种群生命表.结果表明: 取食含有不同浓度Pb²⁺的人工饲料后,各虫态甜菜夜蛾体内Pb²⁺的浓度在同一世代不同处理间存在显著差异,且呈显著的剂量 反应关系.各虫态体内Pb²⁺的浓度基本上随胁迫世代数的延长而增加.受Pb²⁺胁迫后,各虫态体内Pb²⁺的浓度顺序为5龄幼虫＞成虫＞蛹;该虫可通过粪便、预蛹蜕和蛹壳排泄体内部分重金属,且粪便和预蛹蜕中的Pb²⁺浓度远大于蛹蜕中的浓度;根据Pb²⁺不同浓度条件下甜菜夜蛾各虫态的存活率、雌性比和产卵量,构建的种群生命表表明,低浓度Pb²⁺胁迫可促进甜菜夜蛾的种群增长,而高浓度胁迫使种群增长衰退;且随着重金属的持续胁迫,其种群衰退更明显.研究结果为长期、客观评价重金属的危害性以及对重要农业害虫的种群影响提供了借鉴.     

Pb2+在甜菜夜蛾体内的积累及对种群的影响

重金属的污染及其治理是目前倍受关注的生态学问题之一.甜菜夜蛾是我国长江流域及以南地区蔬菜、棉花等作物上的主要害虫,近几年突发趋势明显.本文以甜菜夜蛾为靶标对象,设计5个浓度(0.3、1.2、4.8、19.2、76.8 mg · kg^-1)重金属Pb²⁺处理,探讨处理后甜菜夜蛾各虫态体内Pb²⁺的积累和排泄,并根据甜菜夜蛾各虫态的生长与存活情况,构建了该虫连续3个世代的种群生命表.结果表明: 取食含有不同浓度Pb²⁺的人工饲料后,各虫态甜菜夜蛾体内Pb²⁺的浓度在同一世代不同处理间存在显著差异,且呈显著的剂量 反应关系.各虫态体内Pb²⁺的浓度基本上随胁迫世代数的延长而增加.受Pb²⁺胁迫后,各虫态体内Pb²⁺的浓度顺序为5龄幼虫＞成虫＞蛹;该虫可通过粪便、预蛹蜕和蛹壳排泄体内部分重金属,且粪便和预蛹蜕中的Pb²⁺浓度远大于蛹蜕中的浓度;根据Pb²⁺不同浓度条件下甜菜夜蛾各虫态的存活率、雌性比和产卵量,构建的种群生命表表明,低浓度Pb²⁺胁迫可促进甜菜夜蛾的种群增长,而高浓度胁迫使种群增长衰退;且随着重金属的持续胁迫,其种群衰退更明显.研究结果为长期、客观评价重金属的危害性以及对重要农业害虫的种群影响提供了借鉴.     

The effect of GNA lectin on the α-amylase activity of the beet armyworm,Spodoptera exigua Hb. (Lepidoptera: Noctuidae)

Beet armyworm (Spodoptera exigua Hb.) (Lepidoptera: Noctuidae) is the major pest of sugar beet (Beta vulgaris). Pesticide applications are the main method of the insect control. So, alternative method/s is/are needed to control this insect species. So, in the current study, the effect of Galanthus nivalis agglutinin (GNA) (snowdrop lectin) on beet armyworm α-amylase was studied. Measurement of the amylase activity of the larval midgut fed on artificial diet and sugar beet leaves showed that the enzyme activity was higher when the larvae fed on artificial diet. However, in both cases, the fourth instar larvae had the greatest amylase activity. Thus, fourth instar larvae were offered artificial diet containing 1 and 2% GNA. Both treatments of the lectin significantly reduced the α-amylase activity of the insect. For example, amylase activity of the fourth instar larvae in the control (fed only on artificial diet) was 2.62 Uml^?1 whilst the activity of the enzyme in the two treatments including diet containing 2 and 1% lectin was 1.45 and 1.75 Uml^?1, respectively. The achieved data showed that lectin, in addition to have toxic effect on the larval growth and development, affects the α-amylase activity of the insect gut.     

Possible involvement of gut-lumen bacteria in in-vivo proteolytic degradation of Bacillus thuringiensisδ-endotoxins

Larval gu juice from aseptically reared beet armyworm, Spodoptera exigua , exhibited lowered processing activity towards the parasporal inclusion proteins of Bacillus thuringiensis as compared with that from normal larvae. Of the seven aerobic bacteria predominantly found in guts of normal larvae, a Bacillus isolate showed marked proteolytic activity against inclusion proteins. The results suggest the possible participation of gut-lumen micro-organisms in in-vivo degradation and processing of B. thuringiensis δ-endotoxins.     

Comparison of the growth and development of beet armyworm,Spodoptera exigua (Hübner) (Lepidoptera: Noctuidae) on two different diets

Beet armyworm (Spodoptera exigua (Hübner)) (Lepidoptera: Noctuidae) is the most economically important sugar beet (Beta vulgaris) pest worldwide. In this study, a comparison was made between two different diets: one was based on Merkx diet (Holidic diet) and the other was based on sugar beet leaf (Oligidic diet). Results showed that the whole development time from larvae to adult between two diets (Merkx and leaf) was not significantly different. For example, developmental time from first instar larvae to adult in Merkx diet was 11.33?days, whilst developmental time of larvae to adult when larvae fed with sugar beet leaf was 10.33?days. However, analysis of variance showed that in some cases like development time of the first instar, third instar and fifth instar larvae and pupae was significantly different between two treatments (p?<?0.05). Larval weight showed differences when larvae fed on Merkx diet and sugar beet leaves. For example, significant differences were shown between first, third and fourth instar larvae weight when larvae fed on Merkx diet and sugar beet leaves (p?<?0.05). However, significant differences were not observed between weight of second and fifth instar as well as pupae weight when larvae fed on Merkx diet and sugar beet leaves (p?>?0.05).     

Temporal allocation of metabolic tolerance to transgenic Bt cotton in beet armyworm, <Emphasis Type="Italic">Spodoptera exigua</Emphasis> (Hübner)

Digestive and detoxification enzyme activity and nutrient composition were examined in the body of fourth instar beet armyworms, Spodoptera exigua (Hübner), fed on transgenic Bacillus thuringiensis (Bt) and non-Bt cotton for different time periods. Nutrient composition and specific enzyme activities differed significantly between the S. exigua fed Bt vs. non-Bt cotton. At 1, 6 and 24 h, free fatty acid and glucose levels were significantly lower in S. exigua fed on Bt cotton than those fed on non-Bt cotton. S. exigua fed on Bt cotton had significantly higher trypsin and total superoxide dismutase (T-SOD) activities and significantly lower lipase, carboxylesterase and acetylcholinesterase activities than non-Bt fed worms for all feeding time periods. Differences were also observed among feeding times within each cotton variety group. Significantly lower free fatty acid and total amino acid were observed in S. exigua fed on Bt cotton for 24 h than in those fed for 1 h. Significantly lower activities of lipase and trypsin were detected in S. exigua fed on Bt cotton for 24 h than those for 1 and 4 h. However, carboxylesterase and acetylcholinesterase activities in S. exigua fed on Bt cotton for 24 h were significantly higher than those for 1, 4 and 6 h. The interaction between cotton variety and feeding time significantly affected the activities of lipase, trypsin, acetylcholinesterase and T-SOD enzymes in S. exigua. Measuring the temporal allocation of protection and detoxification enzyme activities in the body of S. exigua in response to B. thuringiensis can provide a meaningful evaluation on the metabolic tolerance of herbivorous insects under the continuous selection pressure of a toxic protein.