Sublethal Effects of Metaflumizone on Plutella xylostella （Lepidoptera： Plutellidae）

Metaflumizone is a novel sodium channel blocker insecticide,which has been registered for controling the diamondback moth (DBM),Plutella xylostella (Lepidoptera:Plutellidae) in China.It is unavoidable ...     

Sex-Related Larval Susceptibility of Diamondback Moth,Plutella xylostella （Lepidoptera：Plutellidae） to some Reduced-Risk Insecticides

Five reduced-risk insecticides were compared for their toxicities to male and female third instar larvae of diamondback moth （DBM）, Plutella xylostella L. （Lepidoptera：Plutellidae） obtained from a laboratory colony. Leaf-dip bioassays were used to assess larval mortality at different insecticides rates （ranging from 0.01 mg AI/L to 100 mg A1/L） and exposure times （24, 48 and 72 h after treatment）. Toxicity of the insecticides generally increased with rate and exposure time. At 72 h after treatment, median lethal concentrations （LCs0s） of methoxyfenozide, spinosad, novaluron, indoxacarb and Bacillus thuringiensis （Bt） against the male third instar larvae of P, xylostella were 0.0524, 0.1117, 0.9149, 1.1939 and 4.4983 mg AI/L, respectively, and were 0.1008, 0.2583, 1.0649, 0.2850 and 5.3053 mg AI/L against female third instar larvae, respectively. At 0.1% of the approximate recommended field rates, methoxyfenozide （60%-75%） and spinosad （53%-57%） were the most toxic, while Bt （30%-45% mortality） was the least toxic to male and female P. xylostella larvae. Spinosad was the fastest acting and the only insecticide that caused significant larval mortality （17%） at 24 h after exposure. Significant sexual differences were recorded in the susceptibility of P. xylostella larvae to two of the insecticides： spinosad and indoxacarb. Male larvae were two-fold more susceptible to spinosad but 10-fold more tolerant to indoxacarb than female larvae.     

Effect of Host Plants on Development,Fecundity and Enzyme Activity of Spodoptera exigua （Hübner）（Lepidoptera：Noctuidae）

The beet armyworm,Spodoptera exigua (Lepidoptera:Noctuidae),is an economically important pest of crops worldwide,attacking plants from over 20 families including trans-continental agricultural cotton,corn and citrus crops.In this study,performance and subsequent enzyme activity of beet armyworm reared on host plants from five families were investigated.Significant differences were found in development,fecundity and enzyme activity on different host plants.Survival rate was the highest (42.8％) on asparagus lettuce (Lactuca sativar var.asparagina) and the lowest (17.0％) on sweet pepper (Capsicum annuum).Larval duration was the shortest on asparagus lettuce (12.0 d),and was 43.4％ longer on sweet peppers (21.2 d).The activity of acetylcholine esterase (AChE) and carboxylesterase (CarE) in 3rd instar larvae,and soluble carbohydrate and crude protein contents in different host plants were determined.AChE activity was the highest in the larvae feeding on Chinese cabbage (Brassica rapa),but declined by nearly 60％ on maize (Zea mays) seedlings.The ratio of soluble carbohydrate content to crude protein content in host plants was found to have a positive effect on oviposition and a negative correlation with larval duration and life time (from larval to adult stages) of the insect.     

Lethal and Sub-Lethal Effects of Transgenic Rice Containing cry1Ac and CpTI Genes on the Pink Stem Borer,Sesamia inferens（Walker）

Lethal and sub-lethal effects of transgenic rice containing crylAc and CpTI genes on the pink stem borer, Sesamia inferens,were studied to collect information for ecological risk assessment on insect-resistance of transgenic rice. In vitro insectfeeding bioassays were conducted to evaluate the lethal and sub-lethal effects oftransgenic flee lines (Ⅱ YouKF6 and KF6)containing crylAc+CpTI genes on S. inferens at four different growth stages, viz., seedling, tillering and elongation, booting,and milk and maturing. Transgenie rice at seedling stage showed significantly high lethal effect on S. inferens with the shortest lethal duration for 50 and 100% individuals and the highest corrected mortalities after feeding on transgenic lines at this stage for 3 and 6 d. Followed by tillering and elongation stage, 50 and 100% S. inferens were dead after feeding on transgenic lines at this stage for 4 and 10 d, respectively. Moreover, corrected mortalities for 6 d feeding on transgenic lines at this stage were significantly higher than that at booting, and milk and maturing stages. Lethal effect of KF6 on S. inferens decreased significantly at booting stage. Lethal duration for 50% S. inferens significantly extended and its corrected mortalities for 6 d feeding also declined remarkably. However, lethal effect of Ⅱ YouKF6 on S. inferens did not decrease significantly at this stage. Transgenic rice at booting, and milk and maturing stages did not show significant lethal effect to S. inferens and it showed the longest lethal duration for 50% individuals and the lowest corrected mortalities for 3 and 6 d feeding. A few larvae of S. inferens could survive, pupate and emerge on these two transgenic lines at booting, and milk and maturing stages. Sub-lethal effect of two transgenie lines on S. inferens also differed significantly between different developmental stages. Continuously feeding on transgenic rice lines at seedling, and tillering and elongation stages delayed the development of larvae and pupae and decreased pupation rate, but no effect was observed on eclosion rate. Larval development was significantly inhibited after feeding on transgenic rice at booting stage, but no obvious effect was observed in pupal stage, pupation and eclosion rate. There were no significant differences for larval and pupal development, pupation,and eclosion rates between feeding on transgenic and control rice lines at milk and maturing stage. Larval and pupal weights significantly declined, but no influence was observed on fecundity when S. inferens infested on transgenic rice at any stage.These showed that there were significant differences in lethal and sub-lethal effects of transgenic rice on S. inferens among developmental stages, and the effects gradually decreased with the increase of growth stages of rice plant.     

Negative Effects of Oxytetracycline on Wheat （Triticum aestivum L.） Growth,Root Activity,Photosynthesis, and Chlorophyll Contents

A solution culture experiment was performed to investigate the effects of oxytetracycline (OTC) on wheat (Triticum aestivum L.) growth,chlorophyll contents,and photosynthesis at five levels of 0,10,20,40,and 80 mmol L-1 OTC.OTC is toxic to wheat.The wheat growth,especially wheat root was significantly decreased.Further OTC also significantly decreased root activity,chlorophyll contents,and photosynthetic parameters except for intercellular CO2 concentrations.The different responses of indicators such as root number,root activity and so on to OTC were also observed.The IC50 values for the tested indicators to OTC ranged from 7.1 to 113.4 mmol L-1 OTC.The order of indicator sensitivity to OTC was root number ＞ stomatal conductance ＞ chlorophyll a ＞ total chlorophyll ＞ photosynthetic rates ＞ total surface area ＞transpiration rate ＞ chlorophyll b ＞ fresh weight of root ＞ dry weight of root ＞ total length ＞ dry weight of shoot =fresh weight of shoot＞ total volume.The root number was more sensitive than other indicators with the ICs0 value of 7.1 mmol L-1 OTC,and could be taken as the sensitive indicator to predict the hazards of OTC to wheat.     

Effects of Glutamate and Na＋ on the Development and Enzyme Activity of the Oriental Migratory Locust,Locusta migratoria manilensis （Meyen） in Successive Generations

Rapid and mass rearing ofLocusta migratoria manilensis is an urgent need to meet the increasing demand for food of people. In this study, the effects of four artificial feeds on the development, reproduction and the activities of detoxification and protective enzymes of L. migratoria manilensis in three successive generations were investigated. The results showed that sucrose and monosodium glutamate （MSG） significantly increased the net reproductive rate （R0） and the intrinsic growth rate （rm） ofL. migratoria manilensis, but sodium chloride （0.17%） suppressed this increase. Furthermore, the artificial feed with sucrose and monosodium glutamate increased the activities of esterase （EST）, acetylcholinesterase （ACHE）, glutathione-S- transferase （GST）, multi-function oxidase （MFO）, phenol oxidase （PO）, catalase （CAT） and peroxidase （POD）, but inhibited the activity of superoxide dismutase （SOD）. However, sodium chloride （0.17%） increased the activities of EST, ACHE, CAT and SOD, and inhibited the activities of MFO, GST, PO and POD. Correlation analysis found that the increasing of PO activity and the decreasing of SOD activities were significantly related with the increasing of the intrinsic growth rate （rm）. The above results indicated that sucrose and monosodium glutamate could promote the development and reproduction of L. migratoria manilensis, but Na＋ inhibit such promotion with the concentration above 0.2%. The activities of PO and SOD can be used as biochemical standard to assess the effect of artificial feed.     

Changes of the Biomass and Acid Phosphatase Activity in Maize （Zea mays L.） Lines Under Low-P Stress

A pot culture trial was conducted to investigate the changes of the biomass and acid phosphatase （APase） activity in 10 maize lines under low-P stress. P-deficiency significantly decreased the biomass, but induced the significant enhancement of the APase activity. Since P-deficiency had smaller effects on the low-P tolerant maize lines compared with P-sensitive lines, it was demonstrated that differences of tolerance to P-deficiency existed among 10 different maize lines. In addition, the relative biomass and APase activity changed during the vegetative stage of development, and there existed a significant correlation between the biomass and APase activity under low-P stress. These results suggest that the biomass and APase activity can be regarded as indicative traits of maize lines for tolerance to low-P stress at seedling stage.     

A New Strain of Entomopathogenic Bacillus of the Tea Pest,Eterusia magnifica （Butl.） （Zyganiidae： Lepidoptera） from Darjeeling Foothill Region of India

An entomopathogenic strain of Bacillus sp. was isolated from diseased red slug caterpillars of the leaf-feediug pest of tea, Eterusia magnifica, from the Darjeeling foothill region. Analysis of the bacterimn based on polyphasic approach such as growth phase, biochemical tests, whole body＂ protein, crystal protein profiles along with bioassay （i.e. LC50 and LT50 values） established it as a different strain but close to Bacillus thuringiensis kurstaki （Btk）, the commercial microbial pesticides of lepidopterans. Among biochemical parameters differences were noted between the new strain and Btk in ONPG, lysine decarboxylase, omithin decarboxylase, urease, nitrate reduction, V-P and glucose utilization tests. PAGE analysis of the whole body protein for the new strain recorded a 34 kDa band which was absent in Btk （used as reference）. Crystal protein profile of the newly isolated bacterial strain showed 53 and 49 kDa bands whereas in Btk only 52 kDa band was evident. Although the LC50 values of the new strain and Btk were close, their LT50 values were much different, the new strain showing a lower value than Btk. In light of the above differences and in absence of any report of entomopathogenic bacterial strain of E. magnifica, the isolated strain of Bacillus appeared to be new to science and hence was designated as RS01. The new strain opens up the possibility of its futttre use as microbial pesticide after standardizing its formulation and checking its safety aspects.     

Sub-Lethal Effects of Fenvalerate on the Development,Fecundity, and Juvenile Hormone Esterase Activity of Diamondback Moth,Plutella xylostella (L.)

The toxicities of fenvalerate (20% EC) to the 3rd instar larvae of diamondback moth (DBM), Plutella xylostella (L.), reared on three host plants viz., radish, oilseed rape, and cabbage were tested. The LC50 values of fenvalerate to the 3rd instar larvae of DBM varied with host plants, however, there wasn’t any significant difference among them (P 0.05). Similarly, DBM fed on three host plants had same pupal weight, pupal period, pupation rate, adult emergence rate, female ratio, and fecundity. The activity of juvenile hormone esterase (JHE, EC 3.1.1.1) in the 3rd instar larvae of DMB did not significantly vary with host plants, either. These suggested that DBM had similar fitness on the three host plant species. When fed on the host plants pretreated with fenvalerate at the concentrations equivalent to LC20, LC50 and LC80, the pupation rate, pupal weight, adult emergence rate, female ratio, fecundity, and JHE activity of the tested insects were declined as compared with insects in control treatments fed on the same host plant species. Furthermore, the pupal period of the tested insects was extended after fenvalerate treatment. The decrease in JHE activity after fenvalerate treatment in the tested insects could partly explain the changes in the mentioned growth parameters. Whether the role of fenvalerate in the inhibition of JHE activity could serve as a new way to control DBM needs further investigation.     

小菜蛾成虫对十字花科9种植物挥发性物质的触角电生理反应

采用昆虫触角电位测定方法,以十字花科9种植物挥发性物质为对象,研究小菜蛾雌、雄成虫对不同浓度植物挥发性物质的触角电位反应.试验结果表明:六碳醇或六碳醛均能引起较强的EAG反应,如正己醛、反-2-己烯醛、正己醇,而萜烯类化合物如(1R) -(+)-α-蒎烯、α-萜品烯,(+)-3-莰烯、桉树脑和D-柠檬烯激发的EAG相对...     

生态控制配套措施对小菜蛾种群的控制研究

应用害虫种群系统的理论和方法,以苏云金杆菌(Bt)、赤眼蜂(Techogrammer confursam)、性诱剂为基本措施,辅以小菜蛾颗粒体病毒(Plutella xyloste UaGranulosisvirus,PxGV)、爱比菌素(Abamectin)和印楝素等非化学杀虫剂,组配成9种生态控制配套措施,评价其对小菜蛾的控制作用。其中7套措施可将小菜蛾种群趋势指数(Ⅰ)持续控制在1．0以下,不同地区可合理选择使用。     

小菜蛾细胞色素P450基因的cDNA片段克隆及其序列分析

以小菜蛾[Plutella xylostella(L.)]3龄幼虫(对氰戊菊酯的LC50为38.75 mg/L)的总RNA为模板,利用简并引物,采用反转录-多聚酶链式反应(RT-PCR)方法扩增出1个长度为240 bp的cDNA片段。序列分析结果表明,扩增出的cDNA片段与细胞色素P450的Cyp6基因有较高的同源性。     

唑虫酰胺对小菜蛾的亚致死效应研究

为了解唑虫酰胺对小菜蛾实验种群的亚致死效应,为小菜蛾的综合防治提供理论依据,采用浸叶法确定了唑虫酰胺对小菜蛾3龄幼虫的亚致死剂量（ LC30和LC50）,研究其对小菜蛾的生长发育、繁殖及其体内解毒酶的影响。结果表明,经唑虫酰胺亚致死浓度（ LC30和LC50）处理后,小菜蛾幼虫体质量与蛹质量减轻,幼虫历期和蛹期明显延长,成虫寿命缩短,羽化率、单雌产卵量与卵孵化率亦均低于对照,小菜蛾3龄期幼虫体内的酯酶、谷胱甘肽-s-转移酶和多功能氧化酶活性均显著低于对照。亚致死浓度的唑虫酰胺对小菜蛾的种群增长有一定的抑制作用,对小菜蛾体内的酯酶、谷胱甘肽-s-转移酶和多功能氧化酶均有明显的抑制作用。这一结果可为唑虫酰胺的科学应用以及制定小菜蛾综合防治策略提供理论依据。     

小菜蛾寄生性天敌的动态调查与作用分析

停止使用化学杀虫剂1年后,调查梅菜不同品种上小菜蛾寄生性天敌的寄生作用。结果表明,菜蛾绒茧蜂(Cotesia plutellae)在矮脚白梗仔、三联种上发生2个世代,高峰期分别为11月中下旬与1月上中旬,其平均寄生率分别为20.83%与31.73%、16.71%与22.63%。菜蛾啮小蜂(Oomyzus sokolowskii)在矮脚白梗仔、三联种上发生1代,高峰期为11月20日,寄生率分别达28.75%、26.00%。将寄生性天敌的作用合并,早中熟品种上寄生性天敌的作用比晚熟品种强。其中以矮脚白梗仔和大梗齐尾品种上的寄生作用最大,排除作用控制指数EIPC(Exclusive index of population control)分别为2.634 1和2.355 0,即如果排除寄生性天敌,小菜蛾将分别增长2.634 1倍、2.355 0倍。晚熟品种矮脚黒叶仔、陂(B)种上寄生作用较强,EIPC分别为1.639 9和1.589 4。     

小菜蛾研究的概况与进展

简述了小菜蛾（Plutella xylostella)在种群饲养，生物学，生态学特性，天敌昆虫,病原微生物、寄主植物及抗药性研究方面的概况与进展，对不同饲养方法的特点，已报道的生长发育起点温度，有效积温常数值以及与小菜蛾生长发育有关的空气相对湿度范围，光照对成虫交尾行为的影响情况进行了比较。     

小菜蛾对阿维菌素的抗药性研究进展

小菜蛾是十字花科蔬菜的重要害虫,阿维菌素是目前防治这一害虫的当家产品。笔者对小菜蛾抗阿维菌素品系的选育、抗性监测、交互抗性、抗性遗传、抗性机理等方面的研究进展进行了综述。     

10%阿维·毒乳油对小菜蛾的田间药效评价

经过两年田间试验结果表明,10%阿维.毒乳油1500m l/hm2,药后3~7d对小菜蛾的防效为85.43%~87.03%,与对照药剂1.8%集琦虫螨克乳油450m l/hm2的防效相当,而与48%毒死蜱乳油600m l/hm2的防效达极显著差异。     

60种植物提取物对小菜蛾的杀虫活性筛选

用浸虫浸叶法测定了广西地区60种植物甲醇提取物对小菜蛾Plutella xylostella(L.)三龄幼虫的生物活性,结果表明,对小菜蛾具有较高毒杀活性(校正死亡率50%以上)的植物有山茶科的木荷、油茶,茄科的颠茄,大戟科的三年桐,含羞草科的猴耳环,即4科5种,其中木荷的毒杀活性最高,72 h后的校正死亡率达到100%。其次为油茶、颠茄、三年桐、猴耳环,72 h后的校正死亡率分别为98.50%,84.60%,66.70%,59.00%。