喷雾和灌根施药后吡虫啉在草莓植株中的分布及其对草莓蚜虫的防效

采用喷雾和灌根两种施药方法,设置高、低两个浓度,测定吡虫啉在草莓植株中的分布及对草莓蚜虫的防效。结果表明,喷雾处理区,草莓叶片中吡虫啉初始沉积量高于茎,叶片中持留的吡虫啉消解较快,而茎中消解较慢;灌根处理区,叶片中吡虫啉积累量于药后7 d达到最大值,之后缓慢减少,茎中吡虫啉持留量在药后1~28 d相对稳定。随着时间推移,不同施药方法对蚜虫的防效不同。喷雾法短期防效(7 d内)优于灌根法,但持效期较短。灌根施药法速效性较差,但持效期长,药后7~28 d防效保持在70%以上。同时,随着施药浓度的增加,灌根法的速效性有良好的提升。     

5种杀虫剂灌根施药对黄瓜烟粉虱的防治效果研究

以盆栽黄瓜为供试植物,利用灌根法,研究了5种杀虫剂对黄瓜烟粉虱的防治效果。结果表明:阿维菌素对黄瓜烟粉虱最高防效不足30%,吡虫啉、噻虫嗪、啶虫脒和烯啶虫胺灌根施药后7d,防效均在60%以上,10d防效达最高,其中吡虫啉130mg/L处理防效最高为94.3%,持效期长达20d。本研究为黄瓜烟粉虱防治药剂的合理使用提供了科学依据。     

甲维·吡丙醚8.5%乳油及其复配组合对烟粉虱的田间防效评价

为筛选防治烟粉虱的有效药剂,采用田间试验的方法比较不同药剂(组合)对烟粉虱的防治效果.结果表明甲维·吡丙醚8.5%乳油30mL/667m2 氯噻啉10%可湿性粉剂30g/667m2无论从速效性,还是持效性来说均优于其他处理,且对作物安全.因此可在生产上推广使用.     

甲维·吡丙醚8．5％乳油及其复配组合对烟粉虱的田间防效评价

为筛选防治烟粉虱的有效药剂,采用田间试验的方法比较不同药剂（组合）对烟粉虱的防治效果。结果表明甲维·吡丙醚8．5％乳油30mL／667m^2＋氯噻啉10％可湿性粉剂30g／667m^2无论从速效性,还是持效性来说均优于其他处理,且对作物安全,因此可在生产上推广使用。     

喷雾助剂对不同剂型吡虫啉药液理化性能与沉积的影响

为明确4种不同类型喷雾助剂对吡虫啉5种剂型的增效效果,测定了助剂与农药混用后药液的表面张力、接触角、干燥时间、扩展直径与叶面持留量,之后根据上述试验结果,选择增效作用较好的2种助剂与吡虫啉各剂型混用,对枸杞木虱进行大田防效试验,最终得到喷雾助剂与农药剂型的最优搭配。试验结果表明,添加喷雾助剂可降低药液表面张力、接触角与干燥时间,增加药液在枸杞叶片上的扩展直径与叶面持留量。其中,强力源对5%吡虫啉SL、70%吡虫啉WP的增效效果较好,矿物油对5%吡虫啉SL、70%吡虫啉WG的增效效果较好,迈润与步锐丝效果相对较差。田间试验结果表明,强力源分别与70%吡虫啉WP和5%吡虫啉SL混用防治枸杞木虱,药后7、10 d的防效较好。表面活性剂类助剂强力源可有效改善5%吡虫啉SL、70%吡虫啉WP药液物理性能,增加药液在叶片上的沉积量,并有效防治枸杞木虱,故生产上推荐使用该搭配。     

不同类型药剂防治设施番茄烟粉虱的效果

采用小区试验对常用于烟粉虱防治的16种药剂在推荐剂量下分类型进行了筛选.发现新烟碱类杀虫剂和菊酯类杀虫剂对当地设施番茄上的烟粉虱防效均较高,药后7d防效分别为90.3％～94.2％和88.6％～92.1％;昆虫生长调节剂类杀虫剂的防效不明显,药后7 d防效为62.6％～67.8％;其他类药剂矿物油防效较低,螺虫乙酯因在...     

三种药剂喷雾和灌根施药方式对西花蓟马的残留毒力

选取生产中常用的阿维菌素、噻虫嗪和螺虫乙酯,分别采用喷雾和灌根的方式施于甘蓝、甜椒和菜豆上,药后不同时间分别取3种作物上的老叶片及新生叶片,采用离心管法测定其对西花蓟马的残留毒力.结果表明,噻虫嗪灌根对西花蓟马的残留毒力最高,持效期长达一个月左右,可作为防治苗期西花蓟马的有效药剂和方法.     

8种不同类型杀虫剂对MED烟粉虱隐种的防治效果及其残留检测

为筛选对设施蔬菜烟粉虱具有高效、低毒、低残留的化学农药,选用8种分属于不同类型的杀虫剂对设施黄瓜和茄子上的MED烟粉虱隐种进行了药效试验和农药残留检测。结果表明,药后10d,8种杀虫剂对黄瓜田MED烟粉虱的防效为78.98%~96.66%,而对茄子田MED烟粉虱仅为39.59%~81.11%。新型杀虫剂10%溴氰虫酰胺OD和50%氟啶虫胺腈WG对MED烟粉虱防效高,药后10d对黄瓜田MED烟粉虱的防效分别达94.90%和94.18%,对茄子田MED烟粉虱的防效分别达75.24%和81.11%;3种新烟碱类杀虫剂药后10d对黄瓜田MED烟粉虱防效为78.98%~89.22%,对茄子田MED烟粉虱的防效60.58%~79.09%。酰肼类拟脱皮激素类240g/L甲氧虫酰肼SC药后10d对黄瓜田和茄子田MED烟粉虱的防效分别为80.79%和80.41%。10%溴氰虫酰胺OD中添加增效剂乙氧基改性聚三硅氧烷可使药后3~14d防治效果显著提高1.86%~67.40%。残留检测结果表明,在推荐使用剂量下,药后15d黄瓜茎叶中噻虫嗪和啶虫脒的平均残留量分别为0.52mg/kg和2.06mg/kg,茄子茎叶中阿维菌素、吡蚜酮、甲氧虫酰肼的平均残留量为0.031mg/kg、2.36mg/kg和4.75mg/kg,均高于我国对果实的最大残留限量标准,而黄瓜果实样品中7种杀虫剂均未检出(0.01mg/kg)。研究表明,10%溴氰虫酰胺OD和50%氟啶虫胺腈WG是防治设施蔬菜MED烟粉虱较为理想的新型杀虫剂。     

噻虫嗪对丽蚜小蜂寄生烟粉虱的影响

为了明确噻虫嗪对烟粉虱天敌昆虫丽蚜小蜂Encarsia formosa的影响,在室内模拟田间噻虫嗪灌根和叶面喷雾2种施药方式,研究了施药后丽蚜小蜂的直接死亡率及其寄生Q型烟粉虱的生物学参数。结果表明,经噻虫嗪叶面喷雾后,丽蚜小蜂的死亡率高达98.10%,显著高于其它处理,丽蚜小蜂对烟粉虱若虫的寄生率为5.26%,显著低于其它处理;与清水对照相比,经噻虫嗪处理后丽蚜小蜂对烟粉虱的致死率降低,且叶面喷雾处理大于灌根处理;噻虫嗪灌根和叶面喷雾处理对丽蚜小蜂的羽化率和发育历期均无显著影响,但均能显著缩短丽蚜小蜂成虫的寿命。研究表明,噻虫嗪灌根施药方式对丽蚜小蜂的死亡率及寄生率影响较小,可将噻虫嗪灌根施药方式与释放丽蚜小蜂相结合以防治烟粉虱。     

烟粉虱细胞色素CYP6EM1基因的克隆及对吡虫啉抗性的作用

烟粉虱是一种世界性农业害虫,其防治手段以化学防治为主,新烟碱类杀虫剂吡虫啉常年用于防治烟粉虱,田间烟粉虱已经形成严重的抗药性。本研究通过分析烟粉虱吡虫啉抗性和敏感种群,发现细胞色素CYP6EM1基因在吡虫啉抗性品系中上调了4.7倍,进而克隆了其全长基因,进行了荧光定量PCR分析,发现该基因在吡虫啉抗性烟粉虱3龄若虫期和雄虫成虫期过量表达,并且在抗性成虫胸部和腹部过量表达。最后通过RNA干扰的方法使成虫的CYP6EM1基因表达量下降了54.8%,之后发现当烟粉虱暴露于吡虫啉时死亡率显著升高了39.65%,这表明CYP6EM1与烟粉虱对吡虫啉抗性的形成相关。研究结果对于揭示烟粉虱对吡虫啉产生抗性的机制有帮助,也为烟粉虱抗性水平田间监测及烟粉虱综合治理提供理论依据。     

Behavioral hormoligosis in oviposition preference of Bemisia tabaci on cotton

The study on behavioral hormoligosis in oviposition preference in Bemisia tabaci (Genn.) on cotton was conducted, at Entomological Research Farm, Punjab Agricultural University (PAU), Punjab, India, during 2001 crop season and repeated in the same season. Multiple-choice test was followed for conducting the experiment. Quinalphos (250, 375, and 500), carbaryl (625, 938, and 1250), acephate (750, 1125, and 1500), endosulfan (438, 656, and 875), and fenvalerate (25, 38, and 50 g ai/ha) were repeatedly sprayed on potted plants of American cotton (var. LH-1556). The impact of these insecticides was evaluated in term of oviposition preference by B. tabaci to treated plants. Also, it investigated changes in biochemical components of treated cotton leaves and the correlation with oviposition preference. The results revealed that, fenvalerate treated plants were more preferred by whitefly for oviposition. Maximum number of eggs was observed on fenvalerate treated plants, 38, 50, and 25 g/ha (39.3, 37.3, and 36.1 eggs/leaf, respectively) followed by acephate 1500 g/ha (26.9 eggs/ leaf) compared with untreated control (14.1 eggs/leaf). Almost similar trend of results was observed in the repeated experiment. The results obtained from biochemical studies revealed that all the insecticidal treatments caused reduction in total sugars compared with untreated control except fenvalerate and low dose of quinalphos. All insecticides caused increase in total free amino acids and brought significant changes in total phenols and pH value of treated plants. These results have confirmed the behavioral hormoligosis in oviposition preference that induced by fenvalerate and acephate in B. tabaci, which may be one of the causes behind its resurgence on plants repeatedly treated with these insecticides.     

Influence of neem on susceptibility of Beauveria bassiana and investigation of their combined efficacy against sweetpotato whitefly, Bemisia tabaci on eggplant

A study on the compatibility of the entomopathogenic fungus Beauveria bassiana with neem was conducted against sweetpotato whitefly, Bemisia tabaci, on eggplant. Initially, three concentrations of neem (0.25%, 0.5% and 1.0%) were used to investigate the physiological responses of B. bassiana. Thereafter, above three concentrations of neem along with three concentrations of B. bassiana (10⁶, 10⁷ and 10⁸ conidia/ml) were used to investigate combined deterrence index, DI under two application methods (foliar and soil) of B. tabaci. Significant differences were observed among neem concentrations on all variables- germination percentage, vegetative growth, number of conidia, amount of biomass and proteolytic activity of B. bassiana. The reduction percentage of germination, vegetative growth, sporulation, biomass production and proteolytic activity of B. bassiana were as high as 12%, 13%, 35%, 38%, and 34%, respectively, to neem. Significant differences were also observed on deterrence index, DI (adult and oviposition) of B. tabaci. The current study investigated that the highest adult DI (80.15) and oviposition DI (88.25) occurred when 1.0% neem was combined with 10⁸ conidia/ml of B. bassiana. As the results show, neem is compatible with B. bassiana; and soil application of neem along with foliar application of B. bassiana might be useful for the control of B. tabaci.     

Biochemical determination of acetylcholinesterase genotypes conferring resistance to the organophosphate insecticide chlorpyriphos in field populations of Bemisia tabaci from Benin, West Africa

Resistance to chlorpyriphos insecticide in Bemisia tabaci from a field population collected in Benin, West Africa was suggested with bioassay showing the presence of two sub-populations. Patterns of acetylcholinesterase (AChE) inhibition by the organophosphate chlorpyriphos-oxon were analyzed to estimate the number of possible genotypes with different sensitivity expected in three B. tabaci field populations collected in Benin. The analysis of inhibition patterns in these populations compared with four laboratory strains of B. tabaci using chlorpyriphos-oxon allowed the differentiation of three possible genotypes. In the reference strain SUD-S we detected two different acetylcholinesterases with different sensitivity to chlorpyriphos oxon suggesting the presence of two genes ace 1 and ace 2. The proportion of the insensitive enzyme (ace 2) was estimated to be 31%. In field populations we can detect two alleles at the same gene locus ace 1: one susceptible ace1S and one resistant ace1R. Both strains called Arizona University and Mexico-S2 have lost sensitive ace1S but the field populations from Benin clearly contained at least three genotypes confirming heterogeneous populations not completely resistant.     

三种植物次生物质对B型烟粉虱羧酸酯酶活性及其对药剂敏感度的影响

采用人工饲料添加法,研究了不同浓度的槲皮素、2-十三烷酮和葫芦素B 3种植物次生物质对B型烟粉虱Bemisia tabaci羧酸酯酶(CarE)活性的影响,同时比较研究了用3种植物次生物质处理后敌敌畏、脱叶磷、灭多威、乐果和氧乐果5种药剂对CarE 的抑制中浓度(I50)的变化。结果表明: 0.01~1.0 mg/mL的槲皮素对B型烟粉虱成虫CarE活性均具有明显的诱导增加作用,最高为对照的4.32倍; 0.1和0.5 mg/mL的2-十三烷酮处理使CarE活性比对照分别下降了22%和58%; 0.75~30.0 mg/L的葫芦素B对烟粉虱CarE活性均表现为抑制作用;用1.0 mg/mL的槲皮素处理24 h后,敌敌畏和脱叶磷对烟粉虱CarE的I50值分别增加为对照的20.05和3.16倍; 3.75 mg/L 的葫芦素B处理后,敌敌畏和灭多威对CarE 的I50值分别增加为对照的25.94、2.45倍; 1.0 mg/mL的2-十三烷酮处理后敌敌畏、脱叶磷和乐果对CarE 的I50值分别降低了89%、83%和90%。     

寄生Q型烟粉虱的丽蚜小蜂生长发育特性

为了阐明丽蚜小蜂Encarsia formosa对Q型烟粉虱的寄生特性及寄主植物携带病毒对其寄生的影响,采用微虫笼饲养法研究了寄生Q型烟粉虱的丽蚜小蜂生物学特性。结果显示,丽蚜小蜂寄生Q型烟粉虱3龄若虫时,其生长发育显著优于寄生Q型烟粉虱2龄若虫。丽蚜小蜂在感染黄化曲叶病毒（TYLCV）番茄和健康番茄上寄生Q型烟粉虱（分别为VW和NVW）3龄若虫时,其生长发育特性发生了明显变化。丽蚜小蜂以VW若虫为寄主时的寿命为10.25 d,显著长于寄生NVW的丽蚜小蜂寿命（5.90 d）;对VW和NVW后代3龄若虫的寄生率分别为23.81%和17.62%,致死率分别为38.95%和26.52%,差异均显著;而丽蚜小蜂的羽化率和发育历期不存在显著差异。说明丽蚜小蜂寄生Q型烟粉虱3龄若虫时更适宜其生长发育,寄主植物番茄携带TYLCV显著提高丽蚜小蜂对烟粉虱的寄生效果。     

Two cytochrome P450 genes are involved in imidacloprid resistance in field populations of the whitefly, Bemisia tabaci, in China

The sweet potato whitefly, Bemisia tabaci (Gennadius) (Hemiptera:Aleyrodidae), is an invasive and damaging pest of field crops worldwide. The neonicotinoid insecticide imidacloprid has been widely used to control this pest. We assessed the species composition (B vs. Q), imidacloprid resistance, and association between imidacloprid resistance and the expression of five P450 genes for 14–17 B. tabaci populations in 12 provinces in China. Fifteen of 17 populations contained only B. tabaci Q, and two populations contained both B and Q. Seven of 17 populations exhibited moderate to high resistance to imidacloprid, and eight populations exhibited low resistance to imidacloprid, compared with the most susceptible field WHHB population. In a study of 14 of the populations, resistance level was correlated with the expression of the P450 genes CYP6CM1 and CYP4C64 but not with the expression of CYP6CX1, CYP6CX4, or CYP6DZ7. This study indicates that B. tabaci Q has a wider distribution in China than previously reported. Resistance to imidacloprid in field populations of B. tabaci is associated with the increased expression of two cytochrome P450 genes (CYP6CM1 and CYP4C64).     

吡虫啉包衣对黄瓜瓜蚜的防治效果及包衣后药剂在植株体内的分布

为探讨吡虫啉包衣对黄瓜瓜蚜的防治效果及包衣后吡虫啉在黄瓜植株体内的分布动态,以不同剂量的40%吡虫啉悬浮种衣剂包衣处理黄瓜种子,并测定了不同时间内其对瓜蚜Aphis gossypii Glover的防治效果,同时使用HPLC检测了瓜苗出土后不同时期吡虫啉在黄瓜植株各部位的分布量。结果表明,100 kg黄瓜种子用吡虫啉(有效成分)240 g、480 g和960 g的处理在瓜苗出土35 d后,瓜苗上所接瓜蚜的校正虫口减退率仍分别达到89.2%、92.0%和97.7%。经过吡虫啉包衣处理后的黄瓜种子在出苗后 3~14 d内,植株体内的吡虫啉含量逐渐增加,14 d时达到峰值后逐渐减少; 黄瓜植株不同地上部位中吡虫啉的含量不均匀,其中下部叶片药剂含量最高,其次是上部叶片,茎部最低。     

媒介虫口密度、植株苗龄及温度对B型烟粉虱传播台湾番茄曲叶病毒的影响

台湾番茄曲叶病毒(Tomato leafcurl Taiwan virus,ToLCTWV)近年来在我国部分番茄种植区流行成灾,对番茄生产造成了严重损失。作者研究了B型烟粉虱对ToLCTWV的获取、保持,并测定了虫口密度、温度及植株苗龄对其传播该病毒的影响。结果表明,B型烟粉虱在感染ToLCTWV的番茄植株上取食0.5h即可在3.3%个体内检测到ToLCTWV DNA,取食48h后,带毒率达100%;ToLCTWV DNA可在B型烟粉虱体内终生存留。B型烟粉虱是ToLCTWV的高效媒介,每株1头带毒烟粉虱取食48h,植株发病率达50%～60%;每株5头取食,发病率达到或接近100%。介体虫口密度及植株苗龄是决定苗期发病程度的重要因子,虫口密度增加,病情指数上升;苗龄增大,病情指数下降。温度对发病率有显著影响,但对病情指数影响不显著。此外,温度与苗龄的互作、虫口密度与苗龄的互作以及三因子之间的互作都对病情指数有显著影响。这些结果提示,培育无病壮苗是防治台湾番茄曲叶病毒病的关键。     

吡虫啉的不同施药方式对丽蚜小蜂的寄生效果评价

烟粉虱Q隐种是近几年新传入我国的入侵烟粉虱,主要危害蔬菜、棉花和花卉等经济作物,对多种化学农药都产生了很高的抗药性。为了了解吡虫啉不同施药方式对丽蚜小蜂控制烟粉虱效果的影响,本研究在实验室条件下,调查了经吡虫啉叶面处理和灌根处理两种不同施药方式处理,烟粉虱Q隐种的存活率、丽蚜小蜂的存活率和寄生率。结果表明：1、5、10、50mg·L^-1。浓度吡虫啉灌根处理的丽蚜小蜂校正死亡率分别为21．8％、14．9％、19．3％、16．2％;1、5、50mg·L^-1浓度吡虫啉叶面处理的丽蚜小蜂校正死亡率分别为52．2％、81．8％、93-3％。相同浓度的吡虫啉处理中,叶面处理的丽蚜小蜂死亡率显著高于灌根处理;在吡虫啉和丽蚜小蜂协同作用中,用浓度5、10、50mg·L^-1的吡虫啉灌根处理时,烟粉虱的死亡率分别为41．5％、39．1％、45．9％,丽蚜小蜂寄生率分别为11．9％、15．9％、7．9％;用浓度5、50mg·L^-1的吡虫啉叶面处理时,烟粉虱的死亡率分别为12．6％、37.2％,丽蚜小蜂寄生率均为2％左右。灌根处理对寄生蜂的存活率影响较小,且有利于丽蚜小蜂对烟粉虱的寄生和取食;而叶面处理显著降低了寄生蜂的存活率及寄生率。     

单种或多种寄主植物混合共存对B型烟粉虱成虫的影响

为探究B型烟粉虱Bemisia tabaci(Gennadius)成虫对寄主植物多样性的适应性,采用生态测定和生化方法,比较了油菜、棉花、番茄、黄瓜4种寄主植物同时存在与单种寄主植物存在时对B型烟粉虱存活率、产卵量、总蛋白、海藻糖、超氧化物歧化酶(superoxide dismutases, SOD)、碱性磷酸酶(alkaline phosphatase, AKP)、海藻糖酶、蔗糖酶、淀粉酶等指标的影响.同时,利用“Y”型嗅觉仪,测定了B型烟粉虱雌成虫对4种寄主混合共存和单独存在时的行为反应.结果表明,与单种寄主植物相比,4种寄主植物混合共存时,烟粉虱9 d时存活率显著降低,为(64.0±3.8)%,总产卵量为907±52.5粒,大于棉花,小于油菜、黄瓜,与番茄无显著差异;海藻糖含量及SOD、AKP、海藻糖酶、蔗糖酶、淀粉酶活性相对增大;行为研究表明4种寄主植物混合共存与单种植物存在时相比,除油菜外,B型烟粉虱雌虫对单种植物选择趋性较强.