杀菌剂对斜纹夜蛾SL细胞系和幼虫的生物活性

以MTT法筛选了19种杀菌剂对斜纹夜蛾Spodoptera litura SL细胞的毒杀活性，并以该方法研究了三唑类杀菌剂对SL细胞的毒力。结果表明: 福美双、烯唑醇、己唑醇、氟硅唑、苯霜灵、苯醚甲环唑、戊唑醇和腈菌唑等杀菌剂对SL细胞具有优异的毒杀活性。三唑类杀菌剂腈菌唑、烯唑醇、己唑醇和戊唑醇处理SL细胞48 h后，LC₅₀值分别为21.94 μg/mL、 23.80 μg/mL、 33.16 μg/mL和47.63 μg/mL。以考马斯亮蓝G₂₅₀法研究了腈菌唑对SL细胞中蛋白质含量和乳酸脱氢酶(LDH)漏出率的影响, 20 μg/mL腈菌唑处理12 h、24 h、48 h和72 h后，SL细胞中蛋白质含量分别降低8.55%、25.95%、42.95%和67.05%；处理24 h和48 h后，SL细胞的LDH漏出率分别为30.66%和32.05%。以浸叶喂食法处理斜纹夜蛾3龄幼虫，三唑类杀菌剂可显著抑制试虫体重增长。以0.5 μg/头、 1.0 μg/头和2.0 μg/头剂量的腈菌唑注射处理72 h后，斜纹夜蛾4龄幼虫血细胞数量分别降低12.31%、 25.96%和25.73%；腈菌唑注射处理48 h和72 h后，对斜纹夜蛾幼虫的LD₅₀值分别为1.59 μg/头和1.53 μg/头。结果显示以离体培养细胞为对象，从现有杀菌剂中寻找新的杀虫剂先导化合物具有良好的研究潜力。

Bioactivities of fungicides against Spodoptera litura cells and larvae

The cytotoxicities of 19 kinds of fungicides against Spodoptera litura (SL) cells were studied by using MTT method. The results showed that thiram, diniconazole, hexaconazole, flusilazone, benalaxyl, difenoconazole, tebuconazole and myclobutanil possessed high toxicity against SL cells. The LC₅₀ values of myclobutanil, diniconazole, hexaconazole and tebuconazole, which belong to triazoles fungicides, at 48 h after treatment were 21.94 μg/mL, 23.80 μg/mL, 33.16 μg/mL and 47.63 μg/mL, respectively. Effect of myclobutanil on the protein content and the leakage rate of lactate dehydrogenase (LDH) of SL cells were studied by using colorimetric method of Coomassie brilliant blue G₂₅₀. The reduced rates of protein content of SL cells treated with myclobutanil at concentration of 20 μg/mL for 12 h, 24 h, 48 h and 72 h were 8.55%, 25.95%, 42.95% and 67.05%, respectively. The leakage rates of LDH of SL cells treated with myclobutanil at concentration of 20 μg/mL for 24 h and 48 h were 30.66% and 32.05%, respectively. Triazoles fungicides could decrease the larvae weight of S. litura obviously. The reduced rates of blood corpuscles of the 4th-instar larvae of S. litura treated with myclobutanil at dose of 0.5 μg/larva, 1.0 μg/larva and 2.0 μg/larva by the inject method for 72 h were 12.31%, 25.96% and 25.73%, respectively. The LD₅₀ values of myclobutanil injected into S. litura larvae at 48 h and 72 h after treatment were 1.59 μg/larva and 1.53 μg/larva, respectively. The results suggest that it possesses good research potential that looking for new leading compounds for insecticides from fungicides with vitro cultured cells as object.