Influences of insecticides on toxicity and cuticular penetration of abamectin in Helicoverpa armigera

Synergistic actions for mixtures of abamectin with other insecticides in some insect pests were evaluated, and the possible synergistic mechanism was studied by the comparison in toxicity and cuticular penetration of abamectin between with and without other insecticides or synergists in Helicoverpa armigera larvae. The results of bioassay showed that horticultural mineral oil (HMO), hexaflumuron, chlorpyrifos, and some other insecticides were synergistic to abamectin with 152.0-420.0 of co-toxicity coefficient(CTC) in some agricultural insect pests. In topical application tests, HMO or piperonyl butoxide (PBO) increased the toxicity of abamectin in larvae of H. armigera, but the mortality was not affected by s,s,s-tributylphorotrithioate (DEF) and triphenylphosphate (TPP). The synergistic action of HMO was obviously higher than PBO, and when treated simultaneously with abamectin, HMO gave a more significant synergism than if treated 2 hours ahead. The highest synergistic effect (SE) was found in the mixture of ‘abamectin HMO (1:206)‘. The mortality did not increase or the toxicity drop, when a synergist or HMO was added into the mixture of ‘abamectin HMO‘ or ‘abamectin synergist‘, respectively. Results from the isotope tracing experiments showed that HMO significantly enhanced the penetration of ^3H-abamectin through the cuticle of H.armigera larvae, which resulted in the synergism of the mixture. The cuticular penetration of ^3H-abamectin was not accumulatively affected by chlorpyrifos, nor by hexaflumuron,though there was an inhibition within 30 seconds or 1 hour after treated by these two chemicals respectively. Results suggested that the synergism of abamectin mixed with hexaflumuron or chlorpyrifos might be related to inhibition of metabolic enzymes or target sites in the larvae.     

抗真菌药增效剂的研究现状及展望

近年来,随着真菌耐药问题的日益加剧,许多学者开始专注对抗真菌药增效剂的研究.该文就近年来国内、外对抗真菌药增效剂的研究进展做一综述,以期为未来临床真菌病的治疗及新药研发提供新的思路.     

菜蚜茧蜂对甲胺磷和灭多威的抗性机制

采用试管药膜法测定了菜蚜茧蜂 Diaeretiella rapae 对甲胺磷和灭多威的抗性及增效剂的增效作用,并测定了菜蚜茧蜂和菜缢管蚜 Lipaphis erysimi 乙酰胆碱酯酶动力学参数、解毒酶活性及增效剂对菜蚜茧蜂酶活性的体内抑制作用。福州地区菜蚜茧蜂已对甲胺磷和灭多威产生5.6和9.1倍的抗性,胡椒基丁醚、磷酸三苯酯和马来酸二乙酯对两种杀虫剂的抗性品系均有显著增效作用,胡椒基丁醚的作用最为显著。胡椒基丁醚对抗性菜蚜茧蜂杀虫剂敏感性的增效作用远高于对敏感菜蚜茧蜂的影响。3种增效剂对菜蚜茧蜂乙酰胆碱酯酶均无抑制作用;磷酸三苯酯和胡椒基丁醚对羧酸酯酶,马来酸二乙酯对谷胱甘肽S转移酶有显著抑制作用。抗性和敏感菜蚜茧蜂乙酰胆碱酯酶的米氏常数K_m）、最大反应速度（V_max）、羧酸酯酶及谷胱甘肽S转移酶活性值相近,但敏感菜蚜茧蜂乙酰胆碱酯酶的双分子速度常数（K_I）值远高于抗性的。此外,对菜蚜茧蜂和菜缢管蚜乙酰胆碱酯酶、羧酸酯酶和谷胱甘肽S转移酶进行了比较研究。结果表明菜蚜茧蜂对甲胺磷和灭多威的低水平抗性与乙酰胆碱酯酶的不敏感性及解毒酶的解毒代谢有关。     

昆虫病毒gp37/fusolin基因研究进展

昆虫病毒gp37fusolin基因属病毒复制非必需基因,其编码的蛋白能形成一种纺锤形包涵体(spindlebodies,SBs),该包涵体内不含有病毒粒子。Fusolin蛋白形成的SBs与纯化的Fusolin蛋白均能提高靶昆虫对杆状病毒的敏感性,推测GP37蛋白也具有类似的功能。对gp37fusolin基因的深入研究,有可能开发出新型病毒增效剂 。     

含生物型增效剂棉铃虫病毒悬浮剂的应用效果研究

本文报道含生物型增效剂棉铃虫核多角体病毒(Helicoverpa armigera nucleopolyhedrovirus,HaNPV)悬浮剂对害虫的防治效果及其对天敌数量的影响。作者筛选灭幼脲类似物作为棉铃虫核多角体病毒的生物型增效剂,HaNPV 4．2ppm氟啶脲(chlorfluazuron)感染3龄初棉铃虫幼虫,感染幼虫的半致死时间(LT50)为2．24d,比单用HaNPV感染幼虫的LT50缩短2．66d。含生物型增效剂的棉铃虫核多角体病毒悬浮剂在田间应用,施药后5d,对2代和4代棉铃虫的防治效果分别为81．4％-85．2％和70．7％-82．6％,施药后7d,对2代和4代的防治效果分别为85．2％-86．3％和69．6％-82．9％。棉铃虫病毒悬浮剂中的生物型增效剂对天敌数量仅有轻微影响。含生物型增效剂棉铃虫核多角体病毒悬浮剂不仅能有效控制害虫,而且对天敌有很好的保护作用。     

药用植物源抗真菌药增效剂研究进展

近年来,随着真菌耐药问题的日益加剧,许多学者尝试从药用植物中筛选出对抗真菌药具有协同增效作用的药物.该文就近年来国内、外对植物源性抗真菌药增效剂的研究进展做一综述,以期为耐药真菌病的治疗提供更为安全、有效、价廉的抗真菌药增效剂.     

溴敌隆加增效剂防治林区鼢鼠试验

1992-1994年在陕西北部林区对防鼠药物进行筛选和防治试验。结果筛选溴敌隆作为首选药物进行推广使用,成本低,致死率高,结果表明：加增效剂水杨酸钠后能增强毒饵作用,提高致死率,促使内出血,减少使用浓度,节约饵料和药剂,降低成本,饵料以小麦最好;投饵量每洞10g;插洞法适合林区防鼠。     

OB增效剂对斜纹夜蛾核多角体病毒的增效作用

本文以OB作为斜纹夜蛾核多角体病毒（Spodoptera litura nucleopolyhedrovirus,SpltNPV）的增效剂,对斜纹夜蛾Spodoptera litura幼虫进行生物测定,结果表明,在0．25％-1．00％的浓度范围内,随着OB增效剂浓度的提高,其对斜纹夜蛾核多角体病毒的增效作用也随着提高,最高增效倍数达85．1倍;在2～4龄幼虫范围内,随着虫龄的增大,OB增效剂对斜纹夜蛾核多角体病毒的增效作用也增加;而随着温度的升高,增效剂的增效作用无显著提高。     

钙粘蛋白片断可使Bt毒素增效

苏云金芽胞杆菌（Bt）可以分泌产生有杀虫性的结晶状蛋白，它已被广泛地应用到农业害虫防治中，且起到了重要的作用。钙粘着蛋白Bt—R1是一种结合蛋白，存在于烟草天蛾中肠上皮细胞里，可结合BtCry1A毒素。Adang等科学家先前鉴定出Bt—R1区很接近细胞膜的CR12-MPED区（Cry1Ab介导的细胞毒素途径所必需的一个结合区）。2007年8月28日《PNAS》报道了一个含有CR12-MPED区的肽，并在大肠杆菌中表达，可作为Cry1A毒性的增效剂，防治鳞翅目幼虫。CR12-MPED肽结合在刷状缘膜囊和中肠微绒毛上，但不改变中肠上Cry1Ab或Cry1Ac结合位点。通过BIAcore分析，证明Cry1Ab可结合在CR12-MPED的高、低2个亲合位点上。     

茶皂素对尼索朗杀灭桔全爪螨的增效作用

本文就茶皂素对尼索朗杀灭桔全爪螨的增效作用,进行了室内及田间药效试验。