Functional Response Of Neoseiulus Barkeri And Combining Application With Acremonium Hansfordii On Tetranychus Urticae Koch

The predatory mite Neoseiulus barkeri was used in biological control widely. Its predation capability to a variety of pests(Tetranychid, Thrips, Nematodes and so on) had been studied by many biocontrol reachers, and its fertility and life parameters also had been studied when it ate above-mentioned pests(mites). It is generally considered that Neoseiulus barkeri has the potential as an effective natural enemy to control pest mites and small insects with suck-piercing monthparts. However, by compared with chemical measurement, single biological agents showed slower working slowly, lower lethal rate and so on. If we can use variety of biological agents together, it not only could improve the efficiency of action but also reduce pesticide pollution to the environment and slow down the resistance to insecticides, and finally achieve the sustainable long-term and effective control to pests(mites).This paper have dealt with the functional response of predatory mites Neoseiulus barkeri and combining application with Acremonium hansfordii on sensitive and mixed resistant strains of Tetranychus urticae, and also that potential control of predatory mite on the plant nematodes were studied. The main results are as follows:(1)The functional response of Neoseiulus barkeri to sensitive strains and mixed strains of Tetranychus urticae were in accordance with HollingⅡ equation in the 16-32℃ temperature range. By comparision with the same temperature,the predacious number and predation capacity of mixed strains were all lower than that of sensitive strains of Tetranychus urticae,which indicate that female adult of predatory mites had certain antifeeding effect to resistant strain. This was because Tetranychus urticae would strengthen its adaptability under the long-term drug selection pressures, and maybe cause action became faster, body wall hardening and then added its predatory difficulty, to reduce the predation ability of natural enemy, which lead to lower feeding amount,growth and development period of Neoseiulus barkeri. So this would had disadvantageous influence to population expansion of Neoseiulus barkeri.(2)The pathogenicities of Acremonium hansfordii to Neoseiulus barkeri and Tetranychus urticae were determined by using impregnation method. The results showed that corrected death rate of Acremonium hansfordii to Neoseiulus barkeri in 11 days was less than 4 %, but that of Tetranychus urticae reached above 70 %. Meanwhile, the predation capacity of Neoseiulus barkeri treated by Acremonium hansfordii was not affected, but predation ability of Neoseiulus barkeri to Tetranychus urticae treated by Acremonium hansfordii was increased, especially feeding amount of Tetranychus urticae to female adult mites was obviously increased, nymphs was secondly, and eggs were almost no change. It showed that there were good compatibility and synergism bewteen Acremonium hansfordii and Neoseiulus barkeri.