PESTICIDE EFFECTS ON THE PATHOGENICITY OF CONIDIA OF LECANICILLIUM LECANII TO TETRANYCHUS URTICAE

ABSTRACT The objective of this study was to evaluate the effect of pesticides on the pathogenicity of conidia of Lecanicillium lecanii, strain JAB 02, produced in culture media containing acaricides and insecticides, to the two-spotted mite Tetranychus urticae. A blend was made of insecticides (acephate, cyromazine, endosulfan, formetanate hydrochloride, imidacloprid, methiocarb, methomyl, monocrotophos, thiamethoxam) and acaricides (abamectin and propargite) in the culture media PDA, that was poured into a Petri dishes. After solidification, the fungus inoculation was realized at three points and the dishes were incubated for 16 days at a temperature of 25.5 ± 0.5º C and 12 hours of photophase. After the fungus growth, the colonies were cut out and removed to test tubes containing distilled water and detergent Tween 80Ò. The fungus suspension obtained for each treatment was standardized at 1 x 107 con./mL and 1 mL was sprayed on Canavalia ensiformis leaves. After the spraying, 15 mites were placed on each leaf disk and after 2, 4 and 6 days the mortality was evaluated in a stereoscopic microscope. The presence of acaricides and insecticides in the culture media did not affect the pathogenicity of conidia of L. lecanii, which on the 6th evaluation day presented a confirmed mortality in the range of 47 to 76% on two-spotted mites T. urticae.摘要 本研究旨在评估添加了杀螨剂与杀虫剂的培养基中培养所得的蜡蚧轮枝孢（Lecanicillium lecanii）JAB 02菌株分生孢子，对二斑叶螨（Tetranychus urticae）的致病力。将杀虫剂（乙酰甲胺磷、环丙氨嗪、硫丹、盐酸伐虫脒、吡虫啉、甲硫威、灭多威、久效磷、噻虫嗪）与杀螨剂（阿维菌素、克螨特）混合于马铃薯葡萄糖琼脂（Potato Dextrose Agar，PDA）培养基中，随后倒入培养皿中。待培养基凝固后，于培养基三点接种该真菌，随后将培养皿置于温度为25.5±0.5℃、光照周期12小时的条件下培养16天。待真菌菌落长出后，切取菌落并转移至装有蒸馏水与吐温80（Tween 80）清洁剂的试管中。将各处理所得的真菌悬浮液浓度标准化为1×10^7 孢子/mL，随后取1mL悬浮液喷施于刀豆（Canavalia ensiformis）叶片上。喷施完成后，每个叶碟上放置15头二斑叶螨，分别于接种后2、4、6天借助立体显微镜评估螨类死亡率。培养基中添加杀螨剂与杀虫剂并未影响蜡蚧轮枝孢分生孢子的致病力，在第6次评估时，该菌株对二斑叶螨的致死率可达47%至76%。