亚致死剂量阿维菌素和氟虫睛处理小菜蛾对寄生蜂菜蛾绒茧蜂生长发育的影响

分别在小菜蛾体内的菜蛾绒茧蜂处于卵期、早期幼虫和中期幼虫时,饲喂小菜蛾2龄幼虫亚致死剂量（＝LC₁₀）的阿维菌素和氟虫睛,研究上述杀虫剂处理对寄主体内菜蛾绒茧蜂结茧率和羽化率的影响。结果表明： 在菜蛾绒茧蜂处于卵期、早期幼虫和中期幼虫时,饲喂小菜蛾LC₁₀剂量阿维菌素处理的菜叶后,菜蛾绒茧蜂的结茧率分别下降26.6%,22.8%和5.8%,饲喂小菜蛾LC₁₀剂量氟虫睛处理的菜叶后,菜蛾绒茧蜂的结茧率分别下降76.9%,42.5%和18.5%。上述阿维菌素处理对菜蛾绒茧蜂成虫羽化率影响不显著,但上述氟虫睛处理可显著抑制菜蛾绒茧蜂成虫羽化率,在菜蛾绒茧蜂处于卵期、早期幼虫和中期幼虫时,饲喂小菜蛾LC₁₀ 剂量氟虫睛处理的菜叶可导致菜蛾绒茧蜂成虫羽化率分别下降53.1%,36.1%和47.8%。结果显示,即便是对寄主小菜蛾幼虫很低的剂量（LC₁₀剂量）也会显著危害小菜蛾幼虫体内的菜蛾绒茧蜂的生长发育。此外,饲喂小菜蛾幼虫亚致死剂量杀虫剂对菜蛾绒茧蜂生长发育的影响与杀虫剂种类及蛾绒茧蜂发育阶段有关。     

球形芽孢杆菌对致倦库蚊的后致死作用

研究了球形芽孢杆菌Bacillus sphaericus C3-41菌株对致倦库蚊Culex quinquefasciatus幼虫的毒力及其后致死作用。生物测定表明,该菌株对目标蚊幼虫具有很高的毒力,其丙酮粉剂对3～4龄幼虫48 h的半致死浓度(LC₅₀)为(6.92±0.22) μg/L。用不同亚致死浓度处理2～3龄致倦库蚊幼虫,存活幼虫在后期发育中存在明显的延续死亡和损伤现象,经LC₃₀、LC₅₀、LC₇₀、LC₉₀和LC₉₈剂量的C3.41粉剂处理的致倦库蚊羽化前的总死亡率分别为84%、91%、95%、97%和100%,同时存活的幼虫、蛹和成蚊的发育和行为也受到一定的影响。这种后致死作用随处理浓度的升高而增强,可能同球形芽孢杆菌毒素蛋白对处理期间蚊幼虫中肠上皮细胞造成的损伤相关。     

四种杀虫剂亚致死剂量对中黑盲蝽发育和繁殖的影响

使用瓶膜法确定4种常用杀虫剂（毒死蜱、硫丹、氯氟氰菊酯和吡虫啉）对中黑盲蝽Adelphocoris suturalis Jakovlev 1日龄成虫的亚致死剂量（LC₁₀,LC₂₀和LC₃₀）,并研究了其对中黑盲蝽的亚致死效应。结果表明：4种杀虫剂L₂₀剂量处理成虫均能降低雌雄虫的寿命,延长下一代卵的发育历期,但对卵的孵化率没有显著的影响;毒死蜱和硫丹能缩短产卵前期,氯氟氰菊酯和吡虫啉能降低产卵量。毒死蜱亚致死剂量LC₁₀和LC₃₀处理过的成虫与未处理过的成虫交叉配对后雌雄虫寿命均显著缩短;LC10各交叉处理能够缩短产卵历期,降低单雌产卵量和卵的孵化率,延长卵的发育历期;LC₃₀♀×CK♂和LC₃₀♀×LC₃₀♂的下代若虫存活率为28.00％和36.36％,显著低于对照71.88%。结果说明这4种杀虫剂的亚致死剂量对中黑盲蝽生殖均有不利影响,接触杀虫剂与未接触杀虫剂的成虫交配对其后代也有不利影响。研究对于中黑盲蝽区域性综合防治具有一定的指导意义。     

虫酰肼及其衍生物0593对家蚕的毒性及作用机理

为明确虫酰肼衍生物0593对家蚕Bombyx mori的毒性,本研究采用食下毒叶法测定了虫酰肼及其衍生物0593对家蚕的毒性,观察了亚致死浓度下对家蚕生长发育的影响,并测定了虫酰肼及其衍生物0593对家蚕幼虫体内保护酶的影响,对虫酰肼0593的作用机理进行了初步探索。结果表明：虫酰肼及其衍生物0593对2龄家蚕96 h的LC₅₀值分别为1.2863和0.3364 mg·L^-1,属高毒级药剂;虫酰肼及其衍生物0593在亚致死剂量下对家蚕的生长发育有明显的不利性,可使幼虫历期缩短0.5～2 d;处理组眠期体重、全茧量、蛹重和化蛹率与对照相比均显著降低;对4龄幼虫体内多酚氧化酶和几丁质酶也有较明显影响,虫酰肼及其衍生物0593处理家蚕,处理后6 h对体内多酚氧化酶有明显激活作用,12 h后表现出显著的抑制作用;虫酰肼及其衍生物0593对家蚕体内几丁质酶均有激活作用。0593对保护酶的影响较虫酰肼明显。结果提示虫酰肼及其衍生物0593对家蚕毒性高,对其生长发育和保护酶类均有不利性,不适合在桑园及其周边农田使用。     

低致死剂量氯虫苯甲酰胺对沟金针虫食物利用和相关生理生化指标的剂量和时间效应

【目的】明确氯虫苯甲酰胺对沟金针虫Pleonomus canaliculatus亚致死效应的生理生化机制,阐明氯虫苯甲酰胺低致死剂量对沟金针虫食物利用、能量物质含量以及体内消化酶、保护酶和解毒酶活力的影响。【方法】室内采用土壤混药法测定氯虫苯甲酰胺对沟金针虫3龄幼虫毒力,并测定了氯虫苯甲酰胺LC₁₀, LC₂₅和LC₄₀低致死剂量对沟金针虫3龄幼虫营养指标和体内能量物质含量的影响;采用酶动力学法检测了氯虫苯甲酰胺低致死剂量处理1, 6, 12, 24, 48和72 h后沟金针虫3龄幼虫体内消化酶(蛋白酶、α-淀粉酶、脂肪酶、海藻糖酶)、保护酶(CAT, POD和SOD)以及解毒酶(CarE, MFO和GST)活力的动态变化。【结果】氯虫苯甲酰胺对沟金针虫3龄幼虫有较高毒力,其LC₅₀值为1.2397 mg/kg。LC₁₀和LC₄₀剂量氯虫苯甲酰胺处理沟金针虫3龄幼虫后,平均相对生长率(MRGR)和近似消化率(AD)显著降低,严重干扰其对食物的利用;LC₁₀, LC₂₅和LC₄₀剂量处理后沟金针虫3龄幼虫体内主要的能量物质(蛋白质、脂质、碳水化合物、海藻糖)含量和消化酶活力均明显降低,而解毒酶和保护酶活力显著增加,最终延缓其生长发育。【结论】氯虫苯甲酰胺对沟金针虫幼虫具有很高的杀虫活性,低致死剂量氯虫苯甲酰胺处理沟金针虫幼虫后,通过抑制消化酶活性,使其对食物的利用能力降低和生长发育延缓,以及诱导解毒酶和保护酶活性来阻止外界毒物侵害。研究结果为阐明氯虫苯甲酰胺对沟金针虫的亚致死效应机制及作用机理提供了一定的理论基础。     

阿维菌素和哒螨灵亚致死剂量对土耳其斯坦叶螨实验种群生命表的影响

为了了解阿维菌素和哒螨灵对土耳其斯坦叶螨Tetranychus turkestani Ugarov et Nikolski实验种群的亚致死效应, 为新疆土耳其斯坦叶螨的综合防治提供理论依据, 我们在室内通过叶碟饲养的方法, 利用生命表技术研究了阿维菌素和哒螨灵亚致死剂量对土耳其斯坦叶螨实验种群成螨和卵的影响。结果表明: 阿维菌素和哒螨灵LC₂₀、LC₁₀剂量处理成螨后, 可使成螨的产卵量、平均寿命和卵孵化率显著降低; 卵期、幼螨期、若螨期和产卵前期明显延长, 而成螨期和雌螨寿命又明显低于对照; 对次代种群的影响表现在净生殖率(R₀)、 周限增长率(λ)降低、生存率和平均每雌日产卵率明显降低, 内禀增长率（r_m）由0.37降低至0.17～0.29, 平均世代历期(T)除阿维菌素LC₂₀处理时长于对照外, 其他处理均低于对照, 种群倍增时间(Dt)延长。两种药剂亚致死剂量处理卵后, 内禀增长率（r_m）由0.32降低至0.11～0.22, 净生殖率(R₀)降低, 平均世代历期(T)和周限增长率(λ)降低, 而种群加倍时间(Dt)增长; 幼螨期、若螨期和产卵前期明显长于对照, 成螨期和雌螨寿命显著低于对照; 生存率和平均每雌日产雌率明显降低。这些结果证明, 在亚致死剂量下, 阿维菌素和哒螨灵能够降低土耳其斯坦叶螨种群的发育速率, 这对土耳其斯坦叶螨的综合防治策略的制定有积极意义。     

溴氰虫酰胺亚致死剂量对甜菜夜蛾生长发育及体内解毒酶活性的影响

【目的】探讨溴氰虫酰胺对甜菜夜蛾 Spodoptera exigua (Hübner)的亚致死效应,为甜菜夜蛾的综合防治和溴氰虫酰胺的合理使用提供理论依据。【方法】采用饲料混毒法,测定溴氰虫酰胺对甜菜夜蛾3龄幼虫的毒力,确定其亚致死剂量（LC₁₀和LC₂₅）,并分别用该亚致死剂量处理甜菜夜蛾3龄幼虫,研究其对甜菜夜蛾的生长发育和体内3种解毒酶活性的影响。【结果】以LC₁₀ 和LC₂₅剂量处理甜菜夜蛾3龄幼虫后,幼虫生长受到显著抑制,虫重抑制率分别为11.55%和27.68%;LC₁₀和LC₂₅处理组3龄幼虫到化蛹天数分别比对照组延长0.07和0.20 d;化蛹率显著低于对照组（80.93%）,分别为63.89%和49.43%;成虫寿命显著缩短1.11 d和2.08 d;单雌产卵量和卵孵化率也低于对照组。亚致死剂量溴氰虫酰胺处理甜菜夜蛾幼虫后24-96 h,羧酸酯酶活性和谷胱甘肽-S转移酶活性表现出相似的变化趋势,呈先激活升高、后被抑制降低;而多功能氧化酶活性在药剂处理48 h和72 h均受到不同程度的抑制作用,这种抑制作用与浓度成正比。【结论】亚致死剂量的溴氰虫酰胺对甜菜夜蛾的生长发育有显著抑制作用,对其幼虫体内解毒酶活性也有不同程度的抑制作用。     

埃玛菌素对小菜蛾幼虫的毒力及其对子代种群增长的影响

研究了不同温度下埃玛菌素（emamectin）对小菜蛾Plutella xylostella幼虫的毒力,并用生命表法研究了25℃下埃玛菌素亚致死剂量LC₃₀）处理小菜蛾3龄初期幼虫后对其子代的影响。结果表明,埃玛菌素为典型的正温度系数药剂,对小菜蛾幼虫的触杀毒力在温度16～31℃间提高了10倍左右,口服毒力在相同温度范围内提高1 000倍左右,显示了埃玛菌素对该虫极高的口服毒力。25℃下埃玛菌素亚致死剂量处理当代幼虫后,对其子代的存活和繁殖均有明显影响,处理组和对照组子代的世代存活率分别为3.7%和35.5%,平均产卵量分别为92.4和148.3,种群趋势指数分别为1.8和27.4,净增殖率（R₀）分别为3.66和33.81,内禀增长力（r_m）分别为0.0665和0.0978。     

大菜粉蝶根虫瘟霉菌株转染小菜蛾后侵染力变化及其与寄主血淋巴酚氧化酶活性的关系

源于大菜粉蝶Pieris brassicae的根虫瘟霉Zoophthora radicans菌株R₀通过反复转染小菜蛾Plutella xylostella而分别获得转染菌株R₁、R₃和R₅。用这些菌株对小菜蛾2龄幼虫进行生物测定,发现菌株对寄主的侵染力有随转染次数增加而增强的趋势。接种后第1～6 天,R₀的LC₂₀（孢子数/mm²）分别为14.7、14.5、9.0、7.1、6.0和5.5;R₁的LC₂₀分别为9.6、5.0、4.2、3.6、3.1和3.0;R₃的LC₂₀分别为4.6、2.9、2.8、2.5、2.4和2.2; R₅的LC₂₀分别为5.2、3.7、3.2、2.8、2.6和2.6,接种后同一天菌株 R₃的LC₂₀值最小即侵染力最强。各菌株感染小菜蛾幼虫后可显著激活寄主血淋巴中的酚氧化酶活性,但R₁、R₃和R₅对酚氧化酶的激活程度显著低于原始菌株R₀。各菌株对小菜蛾的侵染力强弱指标log₁₀ (LC₂₀)与其侵染后寄主血淋巴酚氧化酶活性呈明显正相关（0.852<0.95）,表明R0在对新寄主转染过程中逐渐获得了逃避或克服新寄主免疫防御的能力,从而增强对新寄主的侵染力。     

家蚕对马尾松毛虫质型多角体病毒的敏感性

用虫体克隆技术,对马尾松毛虫质型多角体病毒湖南株（DpCPV-HN）进行了分离纯化,鉴定为质型多角体病毒1型。以家蚕春蕾×镇珠杂种F₁代及自交的F₂代4或5日龄幼虫进行毒力测定,以纯化的家蚕质型多角体病毒对F₁代幼虫的毒力测定为对照。结果表明：家蚕品种春蕾×镇珠对家蚕质型多角体病毒敏感,马尾松毛虫质型多角体病毒湖南株能引起其感染发病;马尾松毛虫质型多角体病毒湖南株感染家蚕品种春蕾×镇珠F₁代幼虫和F₂代幼虫28天后的半致死剂量（LD₅₀）分别为885个和18个CPB(质多角体),前者为后者的49倍。马尾松毛虫质型多角体病毒湖南株感染后的家蚕,其结茧率、化蛹率、羽化率、全茧量、茧层量和单蛾产卵数均有所下降,全茧量、茧层量、茧层率和单蛾产卵数与病毒感染剂量之间无显著关联。     

Influence of juvenile hormone analogue on food consumption and digestive enzyme activities in Spodoptera mauritia Boisd

Final instar larvae of S. mauritia treated topically on day 0, 1, 2 and day 3 with a daily dose of 20 microg juvenile hormone analogue (JHA) showed an increase in most of the nutritional parameters such as approximate digestibility, efficiency of conversion of ingested food, consumption index and growth rate. Also, the activities of digestive enzymes amylase, invertase, trehalase and protease increased significantly in JHA treated larvae. The supernumerary larvae formed after JHA treatments showed an increase in the activities of digestive enzymes. Neck-ligated larvae treated with 10 microg JHA exhibited a significant increase in the activities of trehalase and protease. The results demonstrate that treatments of JHA increase the activities of digestive enzymes in the last instar larvae of S. mauritia.     

新烟碱类杀虫剂拌种对马铃薯甲虫幼虫食物利用和生长发育的影响

为研究马铃薯甲虫Leptinotarsa decemlineata（Say）幼虫取食新烟碱杀虫剂噻虫嗪和吡虫啉处理（有效成分18 g/100 kg种薯拌种）播种90 d后马铃薯叶片的消化吸收和生长发育情况,在室内采用重量法测定了幼虫取食量、体重增加量、食物利用率,近似消化率以及蛹重等营养指标。 结果表明：70%噻虫嗪种子处理可分散粉剂拌种后,马铃薯甲虫幼虫的取食量、体重增加量、食物利用率、食物转化率、近似消化率和相对生长率以及蛹重显著低于10%吡虫啉可湿性粉剂拌种和空白对照（P＜0.05）,发育历期显著长于10%吡虫啉可湿性粉剂拌种和空白对照（P＜0.05）;而10%吡虫啉可湿性粉剂拌种后,马铃薯甲虫幼虫的取食量和3～4龄期的体重增加量与空白对照差异显著（P＜0.05）,蛹重、1～2龄幼虫的体重增长量、食物利用率、食物转化率、近似消化率、相对生长率和生长发育历期与空白对照差异不显著（P＞0.05）。 说明70%噻虫嗪种子处理可分散粉剂拌种对马铃薯甲虫幼虫的取食有显著抑制作用,不能很好地满足其生长发育营养物质的需要,幼虫取食其叶片后,近似消化率和相对生长速率显著降低,生长发育历期显著延长。 这有利于减少当季世代数,降低危害。     

Bromatological characterization of mulberry cultivars, Morus spp., and determination of nutritional indexes of Bombyx mori L. (Lepidoptera: Bombycidae)

The objective of this work was to assess, through consumption and utilization of natural food measurements, whether mulberry cultivars, Morus spp., could be recommended to rear the silkworm, Bombyx mori L., in a commercial scale. The mulberry cultivars Miura (standard), Korin and Tailandesa and the hybrids FM 3/3, FM 86, SK 1 and SK 4 were tested. Seventy five fifth-instar commercial hybrid larvae were individualized in gerbox? unities and maintained in a rearing room (25 ± 3oC and 80 ± 10% RH).The mulberry leaves of each of the five cultivars used to feed the silkworm larvae were submitted to bromatological analysis. The dry weight of larvae at the beginning and at the end of the fifth instar, the food consumed and the feces eliminated were recorded to determine the following indexes: relative consumption rate (RCR), relative metabolic rate (RMR), relative growth rate (RGR), approximate digestibility (AD), efficiency of conversion of ingested food (ECI), efficiency of conversion of digested food (ECD), metabolic cost (MC). The bromatological composition analysis of mulberry leaf cultivars revealed that the hybrid SK 4 presented superior nutritional quality compared to the standard cultivar Miura, due to its higher content in crude protein and ethereal extract, and lower detergent fiber content. The hybrid SK 4 was the most adequate food to the silkworm larvae because it was ingested in small amounts, thus providing good digestibility to the larvae, low metabolic cost, good growth rate and one of the highest efficiencies in the conversion of the ingested food and ingested and digested in biomass.     

Effect of DIMBOA on growth and digestive physiology of Sesamia nonagrioides (Lepidoptera: noctuidae) larvae

The hydroxamic acid 2,4-dihydroxy-7-methoxy-1,4-benzoxazin-3-one (DIMBOA) was assessed for its effect on growth and digestive physiology of larvae of the stalk corn borer Sesamia nonagrioides Lef. Nutritional indices and activities of some digestive and detoxification enzymes were determined for larvae feeding on a DIMBOA-containing diet for the first two days of the third instar (short-term feeding assays), and from neonates to third instar (long-term feeding assays). DIMBOA reduced the relative growth rate and the efficiency of conversion of ingested food without affecting the relative consumption rate in long-term feeding assays, but it had no effect in short-term assays. Moreover, elastase-like activity was significantly increased by DIMBOA in short-term feeding assays, whereas microsomal oxidase activity was increased and esterase activity was reduced in long-term feeding assays. In vitro, DIMBOA inhibited the activities of carboxypeptidases, aminopeptidase, glutathione S-transferase and esterase, but it had no effect on trypsin, chymotrypsin and elastase. The implications of the altered levels of proteases and detoxification enzyme activities on the digestive physiology of larvae feeding on DIMBOA-containing diets are discussed.     

Acute toxicity and sub-lethal effects of a pyrethroid (cypermethrin) on survival,development and fitness of Helicoverpa armigera

The chickpea pod borer, Helicoverpa armigera (Hübner) is one of the most destructive pests of India and most of the countries. In this experiment, sub-lethal effects of cypermethrin were evaluated against sixth instar larvae of this pest that had ingested insecticide-treated chickpea pods. The LC₅₀, LC₃₀ and LC₁₀ values of cypermethrin were 80.38, 26.65 and 5.41?mg a.i.?L^?1, respectively, against sixth instar. The sub-lethal effects on fitness, eggs, larvae, pupae, adult longevity and reproduction were observed in H. armigera population that survived exposure to the sub-lethal doses of LC₅₀, LC₃₀ and LC₁₀ of cypermethrin. Survivorship was reduced to 36?days if H. armigera exposed to the sub-lethal dose of LC_50, whereas it was 42?days in unexposed groups. Larvae treated with LC₅₀ dose exhibit lowest intrinsic rate of increase (r_m) (0.0413 females/female/day) and highest (0.0517) with the unexposed group. Time taken by H. armigera to complete one generation (T_c) was 40.09?days, while this time significantly lowered to 32.85?days when exposed to the sub-lethal dose of LC₃₀. Hatching eggs were greatly reduced in the larvae exposed to cypermethrin at all the sub-lethal doses. About 430 eggs/female/generation were recorded after treatment with 80.38?mg/L as compared with untreated females (1390). Larvae that were exposed to sub-lethal concentrations of cypermethrin exhibited lower pupal weight and prolonged pupal developmental times compared control larvae. The overall fitness performance was better in the unexposed population as compared to the population exposed to sub-lethal doses.     

美洲黑杨不同无性系对分月扇舟蛾幼虫的抗性及相关机理

为了选育出在生产上具有推广价值的美洲黑杨Populus deltoides优良抗虫品系,本研究以分月扇舟蛾Clostera anastomosis 3龄幼虫为材料,以I-72杨为对照评价和分析了18个美洲黑杨无性系在实验室条件（28±1℃,RH 70%,16L∶8D）下的抗虫性,通过选择性和非选择性取食实验筛选出了11个具有较强抗性的无性系; 测定了美洲黑杨主要营养物质和次生代谢物质含量,研究了不同无性系对分月扇舟蛾体内保护酶和消化酶活性及对该虫生长发育和食物利用的影响。结果表明：美洲黑杨不同无性系抗性的大小与它们叶片中总酚含量呈明显正相关趋势; 抗性水平不同的无性系对分月扇舟蛾幼虫的生长发育和食物利用有不同的影响,表现在幼虫体重、每日体重增加量、相对生长率、近似消化率、食物利用率和食物转化率等主要生长发育指标的变化上,同时对分月扇舟蛾幼虫取食量和排粪量亦有不同的影响。结果说明,分月扇舟蛾对次生代谢物质的反应更为敏感,抗性无性系对分月扇舟蛾幼虫体内SOD和CAT酶活性有明显的激活作用。     

Detoxification,antioxidant, and digestive enzyme activities and gene expression analysis of Lymantria dispar larvae under carvacrol

Carvacrol is a terpene compound with various biological activities. However, few studies have specifically focused on its insecticidal activity and mechanism of carvacrol. The larvae of Lymantria dispar are seriously harmful herbivorous insect. This study measured the antifeedant, growth-inhibitory, and toxic effects of carvacrol on L. dispar larvae. To further clarify the insecticidal mechanism of carvacrol, the effects of carvacrol on detoxifying enzymes, antioxidative enzymes, digestive enzyme activities, and the mRNA expression of the above-mentioned enzyme genes were investigated. The results of the study showed that the median lethal concentration (LC₅₀) and the sublethal concentration (LC₂₀) of carvacrol were 1.120 mg/mL and 0.297 mg/mL, respectively, at 72 h. After LC₂₀ treatment of L. dispar larvae for 72 h, food intake and weight gain were significantly lower compared with the control. Enzyme activity assays showed that carvacrol significantly inhibited the activities of carboxylesterase (CarE), glutathione S-transferase (GST), and acetylcholinesterase (AchE), and the inhibition rate of AchE activity was highest (66.51%). Carvacrol also activated the activities of superoxide dismutase (SOD) and catalase (CAT), while it inhibited the activities of lipase (LIP) and amylase (AMS), and first inhibited and then activated protease. In addition, qRT-PCR tests showed that carvacrol affected the mRNA expression levels of CarE, GST, AchE, SOD, CAT, LIP, AMS, and protease. This study helps to clarify the insecticidal mechanism of carvacrol on L. dispar larvae.     

Effect of vermicompost on nutrition and intermediary metabolism of Colorado potato beetle,Leptinotarsa decemlineata (Say) (Coleoptera: Chrysomelidae)

Colorado potato beetle (CPB) is the important pest of potato throughout the world. The study showed the effects of vermicompost on nutritional indices, digestive enzyme activities and intermediary metabolism of the larvae and the adults of CPB. Vermicompost affected significantly the efficiency of conversion of ingested food (ECI) and efficiency of conversion of digested food (ECD) in addition to activities of carbohydrases and proteases in both larvae and adults. Amount of total phenol compounds increased in the leaves of the potatoes grown on the soil containing 30% of vermicompost compared to control and it were amended by 15% of vermicompost. In case of intermediary metabolism, activities of aspartate aminotransferase and γ-glutamyl transferase showed no significant differences in the control and the treated larvae, but those were fluctuated upper and lower when 15% of vermicompost was added into growth plots. The amount of low-density lipoproteins (LDL) and high-density lipoproteins (HDL) in the larvae of CPB showed no significant differences among treatments. However, the amounts of LDL, HDL, glycogen and protein of the adults significantly increased using 30% of vermicompost. Results of the current study clearly revealed significant effects on some physiological processes in CPB fed on the plants grown in the different vermicompost treatments.     

Growth versus molting time of caterpillars as a function of temperature,nutrient concentration and the phenolic rutin

Summary A factorial experiment tested the effects of varying nutrient concentration (normal versus diluted), presence or absence of the phenolic allelochemical rutin and daytime temperature (20, 25 and 30° C) on growth, molting and food utilization efficiencies of tobacco hornworms (Manduca sexta). Two of the utilization efficiencies (approximate digestibility and efficiency of conversion of ingested food) were unaffected by temperature; the third one, efficiency of conversion of digested food, was affected by temperature but there was no consistent effect. Lower temperatures significantly increased the proportion of the stadium spent molting, with larvae at a daytime temperature of 20° C spending 9% more of the stadium in molting than larvae at 30° C. Growth time was not influenced by nutrient concentration. When temperature was low and rutin absent, molt time and the proportion of the stadium spent molting were affected by nutrient concentration. Addition of the phenolic rutin did not have an appreciable effect on growth time or digestive processes. However, it increased molting time by 7 to 14% and thus increased the duration of the stadium and reduced relative growth rate. These results indicate that the effect of food quality on growth rate is a function of the thermal conditions of insect herbivores. At cooler temperatures, a disproportionate increase in time spent molting, rather than altered food utilization efficiencies, contributed to lower growth rates. The consequences for larval growth of fluctuating temperatures due to diurnal cycles and the presence of predators forcing larvae into thermally suboptimal microhabitats are discussed.     

Role of Challenger pesticide and plant extracts on some physiological parameters of the cotton leafworm,Spodoptera littoralis (Boisd.)

Fourth instar larvae of cotton leafworm, Spodoptera littoralis (Boisd.), fed on castor bean leaves treated with sub-lethal concentrations of both alcohol and hexane extracts of Egyptian conyza and Challenger 36% SC insecticide as well to study their effects on mortality, food consumption and utilisation of food. The tested insecticides exhibited relatively high mortality in alcoholic extract of Egyptian conyza (5.0% concentration) followed by Challenger (1.0% concentration). Results showed a slight reduction in the consumption index for larvae treated with both alcoholic extract and Challenger at low concentrations, while hexane extract (5%) recorded significant increase. The approximate digestibility (AD) was reduced in all treatments of alcoholic extract and the relative growth rate insignificantly decreased at 5% concentration, whereas AD increased for larvae fed on Challenger 0.25% concentration. The lower concentration of alcoholic extract of conyza and all treatments of Challenger pesticides induced insignificant decrease in the efficiency of conversion of the ingested food, while hexane extract exhibited insignificant increase. Challenger at all tested concentrations achieved insignificant decrease in the efficiency of the conversion of digested food with respect to the control.