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对从未喷药的中国农业大学校园露地栽培的辣根上采集的介壳虫制作成永久玻片后进行鉴定,初步判断为梨绒蚧(Eriococcus tokaedae Kuwana)。将蜡蚧轮枝菌(Lecanicillium lecanii)Bj085-1菌株分生孢子配成(1.4×104)～(1.4×108)孢子/mL的5个处理浓度,对梨绒蚧若虫进行第1次毒力测定。结果显示,各个处理浓度之间的平均累计死亡率大致随着孢子浓度的增加而增加,其中以(1.4×108)孢子/mL浓度处理的最高,但只有45.7%。其后将第1次毒力测定试验中死亡虫体经保湿后出现的菌丝体进行分离纯化,获得了新株系(Lecanicillium lecanii-01Et)进行第2次毒力测定(方法同第1次)。结果表明,不同浓度的L.lecanii-01Et分生孢子对梨绒蚧若虫的杀虫速度随浓度的增加而明显加快,浓度增至(1.4×108)孢子/mL时,杀虫速度最快,LT50仅为3.95 d,平均累计校正死亡率达84.1%。说明分离纯化后的蜡蚧轮枝菌新株系(L.lecanii-01Et)分生孢子对梨绒蚧若虫有较好的防治作用。
Scale insects collected from open-field horseradish cultivated on the campus of China Agricultural University, which had never been sprayed, were made into permanent glass slides, and then identified as Eriococcus tokaedae Kuwana. The conidia of Lecanicillium lecanii Bj085-1 strain were spiked at a concentration of (1.4 × 104) ~ (1.4 × 108) spores / mL for 5 treatments, and the first virulence Determination. The results showed that the average cumulative mortality between treatments increased with increasing spore concentration, with (1.4 × 108) spores / mL being the highest, but only 45.7%. After that, the mycelia that emerged from the dead parasites in the first virulence assay were isolated and purified, and a new strain (Lecanicillium lecanii-01Et) was subjected to the second virulence assay (the same method as the first time) . The results showed that the insecticidal rates of L. conantii-01Et conidiospores on Pestalottidae nymphs significantly increased with the increase of the concentration. When the concentration was increased to (1.4 × 108) spores / mL, the insecticidal speed was the fastest, The LT50 was only 3.95 d, with a cumulative cumulative adjusted mortality of 84.1%. This indicated that the isolated and purified conidia of L. lecanii-01Et had better preventive and therapeutic effects on the pest.