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 本研究旨在评估农药对添加杀螨剂与杀虫剂的培养基中培养的莱氏蛾霉（Lecanicillium lecanii）菌株JAB 02的分生孢子（conidia）致病性的影响，供试靶标为二斑叶螨（Tetranychus urticae）。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、丙炔螨特）混合后加入马铃薯葡萄糖琼脂（PDA）培养基，随后将该培养基倾倒至培养皿中。待培养基凝固后，在培养皿的三个点位接种该真菌，将培养皿置于温度25.5±0.5℃、光照周期12h的条件下培养16天。真菌生长完成后，挑取菌落转移至含蒸馏水与吐温80（Tween 80）的试管中。将各处理组所得的真菌悬浮液浓度标准化为1×10^7 个分生孢子/毫升，取1mL该悬浮液喷雾接种于刀豆（Canavalia ensiformis）叶片上。喷雾接种后，每片叶碟放置15头二斑叶螨，分别于接种后2、4、6天通过体视显微镜评估螨类死亡率。结果表明，培养基中添加的杀螨剂与杀虫剂并未影响莱氏蛾霉分生孢子的致病性；在第6天评估时，其对二斑叶螨的死亡率介于47%至76%之间。