Ismail Manal S M, Soliman Maha F M, El Naggar Moustafa H, Ghallab Mona M
Plant Protection Research Institute, Agriculture Research Center, Ismailia, Egypt.
Exp Appl Acarol. 2007;43(2):129-35. doi: 10.1007/s10493-007-9108-8.
Spinosad is a bioinsecticide with a high degree of selective toxicity towards insects of different orders, but its toxicity towards the two-spotted spider mite (TSSM), Tetranychus urticae Koch (Acari: Tetranychidae) is under debate. In this study, we compared the acaricidal properties of spinosad with the commercial bioacaricide abamectin on the life stages of TSSM. Adulticide and ovicide bioassays were performed on a susceptible laboratory strain using direct spraying of leaf disks with five rates of spinosad (20, 25, 30, 35 and 40 mg/l), five rates of abamectin (0.125, 0.25, 0.5, 1 and 2.5 mg/l), sublethal concentrations or a combination of spinosad and abamectin. Both adulticidal and ovicidal effects of spinosad against T. urticae in the laboratory were apparent, based on morality rates of the adults, reduction of female fecundity and death of offspring. Abamectin was also found to significantly reduce female fecundity and killed offspring when applied directly on the eggs. Interestingly, sublethal concentrations of spinosad reduced female fecundity stronger than abamectin. When a mixture of spinosad and abamectin was applied at LC50, mortality was 74%, fecundity reduction was comparable to abamectin alone and egg hatching rate was lower than by either compound alone. In conclusion, spinosad was more harmful than abamectin for TSSM life stages and the combined application is recommended.
多杀菌素是一种对不同目昆虫具有高度选择性毒性的生物杀虫剂，但其对二斑叶螨（TSSM），即叶螨科的二斑叶螨（Acari: Tetranychidae）的毒性仍存在争议。在本研究中，我们比较了多杀菌素与商业生物杀螨剂阿维菌素对二斑叶螨各发育阶段的杀螨特性。使用易感实验室品系，通过对叶盘直接喷施五种浓度的多杀菌素（20、25、30、35和40 mg/l）、五种浓度的阿维菌素（0.125、0.25、0.5、1和2.5 mg/l）、亚致死浓度或多杀菌素与阿维菌素的组合，进行了成虫icide和杀卵生物测定。基于成虫的死亡率、雌虫繁殖力的降低和后代的死亡情况，多杀菌素在实验室中对二斑叶螨的成虫icide和杀卵作用均很明显。当直接施用于卵时，阿维菌素也被发现能显著降低雌虫繁殖力并杀死后代。有趣的是，亚致死浓度的多杀菌素比阿维菌素更能降低雌虫繁殖力。当以LC50浓度施用多杀菌素和阿维菌素的混合物时，死亡率为74%，繁殖力降低与单独使用阿维菌素相当，且卵孵化率低于单独使用任何一种化合物。总之，多杀菌素对二斑叶螨的发育阶段比阿维菌素更具危害性，建议联合使用。
