Evaluation Of The Control Efficiency On Tetranychus Cinnabarinus By Mixture Of Bifenazate And Other Three Acaricides

Tetranychus cinnabarinus is not only a worldwide dangerous spider mites, but also an important pest in tropical cropssuch as cassava, vegetables, fruit trees and flowers in China. Recently, T. cinnabarinus shows an increasing damage to the tropical crop production, which will greatly restrict safe, efficient and large-scale production of tropical crops. Nowadays the control of T. cinnabarinus still relies on pesticides. However, T. cinnabarinus is quite difficult to be controlled because of its high reproductive capacity, short life circle, serious overlapping of generation and wide ranges of host (over one hundred). Furthermore, applying pesticide in an accessive and high frequency manner would not only cause increasing resistance but also seriously influence non-target organism and environmental safety. Bifenazate is a new type of acyl acetonitrile hydrazide acaricide which was registered in China since 2008. To now resistance of bifenazate was not yet reported in China, thereforehow to use bifenazate scientifically and reasonably, and prolong its service life becomes an important topic.In order to meet the actual demand of "green food" and tropical sustainable agriculture, this study aims to screen the acaricides which is to be rotated and mixed with bifenazate, moreover, the detoxification enzyme based biochemical mechanism of mixed pesticide would be demonstrated. The main research results are as follows:1. 40% pyridaben emulsifiable concentrate (EC)?200g/Lamitraz EC and 73% propargite EC showed favorable control effect to T. cinnabarinus, the laboratory and field 24 h adjusted motalities were all beyond 90%, these acaricides can be used to control T. cinnabarinus with bifenazatealtemately in the field.2. With the effective components ratio of 129:20and 43:4forbifenazate andamitraz,the cotoxicity coefficient (CTC) were 129.7 and 122.3, which showed synergistic toxicity to T. cinnabarinus. With the effective components ratio of 215:73forbifenazate andpropargite, the cotoxicity coefficient (CTC) was135.1, which also showed synergistic toxicity to T. cinnabarinus. With the effective components ratio of 43:8forbifenazate and pyridaben, the cotoxicity coefficient (CTC) was90.76,which also showed additive effectto T. cinnabarinus. These results above indicated that pyridaben, amitraz and propargite were able to be mixed with bifenazate to control T. cinnabarinus in the field.3. The effective components forbifenazate andpropargite (with mixed ratio of 215:73) showed significant inhibition to gtutathione S-transferase (GST) of T.cinnabarinus, moreover, the activities of mixed-function oxidase (MFO),carboxylesterase (CarE) and acetylcholinesterase (AchE) in T. cinnabarinus were not significantly influenced.This study provided theoretical basis for reasonably application of bifenazate and propargite in T. cinnabarinus control.