The toxicity of six insecticides to Myzus persicae and their impacts on stinging behavior
Author of the article:QIAO Li, CHEN-Lei, HUANG Nan-Nan, YUE Shuang-Qi, YOU Wei-Chen, WU Yu-Qing, WANG Guo-Jun
Author's Workplace:Xinyang Agriculture and Forestry University
Key Words:Myzus persicae; toxicity determination; synergistic effect; feeding characteristic
Abstract:
Abstract [Aim] To investigate the toxic efficiency of 6 insecticides against Myzus persicae, providing a theoretical basis for its chemical control. [Methods] Adult M. persicae were reared indoors and the toxicity of 6 insecticides to adult M. persicae was determined using the liquid impregnation method. 6 concentration gradients were established. Based on the toxicity test results, fluosamide and fluonitrile were combined in ratios of 1∶1, 1∶5, 5∶1, 1∶10, 10∶1. Water was for the control treatment. The LC50 and co-toxicity coefficient (CTC) were calculated based on the mortality rate of M. persicae at 0, 2, 4, 6, 12, 24, 36, 48, and 72 h. The electrical penetration graph (EPG) technique was used to monitor the feeding behavior of 5 adult M. persicae across the 6 concentration gradient treatments for each of the insecticides. [Results] The findings indicated that the toxicity and efficacy hierarchy of the 6 insecticides against adult M. persicae was fluonitrile > fluosamide > pyrazine > high efficiency cypermethrin > dipropyl ester > thiothiazide. The results of the combined toxicity test showed that the efficacy of the combined insecticide mixture was higher compared to the individual insecticides. Additionally, there was variation in the synergistic effect. The ratio of fluonitrile to fluosamide was 1∶1, with a CTC value of 3 832.015. The EPG results showed that the duration of the fluonitrile E wave was the shortest (36.16 min) and the least frequent (20.50 times). In contrast, the duration of thiothiazide was the longest (173.82 min) and the most the frequent (48.00 times). When the ratio of fluosamide to fluonitrile was 10∶1, the E wave exhibited the shortest total duration (41.31 min), the least frequent probes (15.50 times), the longest probe duration (105.59 min), and the highest number of probes (29 times). Based on the EPG data, the results were consistent with the toxicity test. [Conclusion] The findings of this study demonstrated the control efficacy of a single dose of fluonitrile combined with fluosamide at a ratio of 10∶1. This mixture could be applied during severe aphid infestations, providing technical support for the effective control of M. persicae.