The Effects Of Insecticides And Prey On The Predatory Mite

We have studied the toxicity of13chemical pesticides to the predatory mites, and the effects of3kinds of food on the growth and development of predatory mites were also detected. Finally, the preference of the predatory mites to3kinds of food and the interaction among the3species of predatory mites were also determined. The major results were as follows:1.In the five types of acaricide, our bioassays found that Above pyridaben presented the highest toxicity but Propargite had the lowest toxicity to the predatory mites. In6kinds of pesticides, Buprofezin performed the highest toxicity but beta_cypermethrin performed the lowest toxicity to the predatory mites respectively. In2kinds of fungicides, mancozeb had the lower toxicity than prochloraz. Furthermore, our data revealed that the sensitivity of the different species of predatory mites to the chemical pesticides was distinct. For example, Ambleseius nicholsi was demonstrated to have the most sensitive response to Propargite, followed by Amblyseius barkeri and Amblyseius cucumeris. However, the three species of predatory mites presented the reverse responses to Above pyridaben in contrast with Propargite, and the response of Amblyseius cucumeris to Above pyridaben was the most significant while Ambleseius nicholsi had the lowest sensitivity.2.Our results indicated that the developmental duration and fecundity of the predatory mites were markedly affected by the food types. The development rate of Amblyseius cucumeris fed on Thrips flavidulus and Panonychus citri Mcgregor was retarded compared with that fed by Aleuroglyphus ovatus. the oviposition period of these females lasted22.7d、23.2d and25.Id respectively. The average number of eggs oviposited by the A. cucumeris females was33.1、34.1and37.5respectively. The oviposition period and the average number of eggs oviposited of Amblyseius cucumeris fed on Thrips flavidulus and Aleuroglyphus ovatus has significant differences with Panonychus citri Mcgregor。However, the development from egg to the adults of Amblyseius barkeri took7.5d,6.4d and7.Id, the oviposition of these females usually lasted22.2d、22.5d and23.4d, and they produced30.1、30.7and31.5eggs on average. The average number of eggs oviposited of Amblyseius barkeri fed on Thrips flavidulus and Aleuroglyphus ovatus has no significant differences.3.The predatory mite represtented significant preference to different preys when Aleuroglyphus ovatus, Thrips flavidulus and Panonychus citri Mcgregor were used as the food source respectively. The quantity of Panonychus citri Mcgregor predated by Ambleseius nicholsi, Amblyseius cucumeris and Amblyseius barkeri was greater than that of Aleuroglyphus ovatus and Thrips flavidulus respectively.4. When the number of prey is50, no significant differences were detected among the offspring number from3species of the predatory mites fed on T. flavidulus and P. citri Mcgregor. However, when the three species of predatory mites were fed by A. ovatus, the number of their offsprings significantly differentiated with each other;. When the number of prey is30,significant differences were detected among the offspring number from3species of the predatory mites fed on A. Ovatus、T. flavidulus and P. citri Mcgregor.