Comprehensive Application Of Pesticide Reduction And Crop Rotation And Predatory Mites To Control Root-knot Nematode

The root-knot nematodes, Meloidogyne spp.. are sedentary endoparasitic nematodes attacking many plants, spreading wildly in the world and containing many species, they are also one of the main pathogens of vegetable production. This research studied the comprehensive application of pesticide reduction and crop rotation to control root-knot nematode in greenhouse, measured the effect of sub-lethal dose of avermectin on the reproductive development and predation ability of Blattisocius dolichu in indoors and studied the control effect of root-knot nematode on the potted Iponoea aqatica with different release modes of B. dolichu. The main results of this research were listed as follows.(1) This research confirmed that root-knot nematodes were increased with continuous cropping of tomato increasing, the control effect of root-knot nematodes was decreased even using nematicides in the process of continuous cropping and increasing the dosage of nematicides could not reduce the damage of root knot nematodes. This research established effective methods of vegetables rotation and pesticide reduction to control root-knot nematodes. It also could control knot-root nematodes effectively by using water spinach rotation and do not use nematicides. Comprehensive application of half the amount of avermectin and chrysanthemum coronarium or lettuce crop rotation could control knot-root nematodes effectively but the control effect of lettuce and water spinach was better than chrysanthemum coronarium.(2) This research confirmed the effect of sub-lethal dose of avermectin on the reproductive development and predation ability of B. dolichu. Three sub-lethal doses of avermectin(LC50, LC30 and LC10) could suppress the predation ability and eggs-laying ofB. dolichu significantly, but no significant effect on the the hatching rate of B. dolichu eggs.The survival time of 30% B. dolichu was significantly prolonged compared to the control, it may be there were B. dolichu has resistant to avermectin.(3) This research confirmed that B. dolichu has a preventive effect to control root-knot nematode. The slow release and broadcast release methods of B. dolichu can effectively reduce the root-knot and the number of oocysts in the water spinach rhizosphere, the plant height increased significantly. The slow release methods of B. dolichu were better than broadcast release methods, but the combination avermectin and B. dolichu could not improve the control effect of root-knot nematodes, therefore, they could not be used at the same time.In conclusion, this research confirmed that appropriate rotation of crops could suppress the number of root-knot nematodes significantly and control the vegetable root-knot nematodes and established effective methods of vegetables rotation and pesticide reduction to control root-knot nematodes. This research also confirmed that three sub-lethal doses of avermectin could suppress the predation ability and reproductive development of B.dolichu and the combination avermectin and B. dolichu could not improve the control effect of root-knot nematodes. It has obvious control effect to root-knot nematodes with B.dolichu and the slow release methods of B. dolichu were better than broadcast release methods.