The Effects And Mechanisms Of Eupolyphaga Frass On Controlling Meloidogyne Incongnita In Greenhouse Tomato

Root-knot nematode(Meloidogyne spp.Chitwood)disease has become a major obstacle to greenhouse vegetable production in China,and become more serious year by year.There was effective on controlling plant diseases when organic waste was soil amendment because there were bioactive substances or that induced by micro-organisms as soil amendment.In our country,a large number of wastes containing different substances(e.g.,slough and chitin)from other organic wastes are produced in medicinal insect farm,and could control nematodes.This paper preliminarily proved the efficiency of eupolyphaga frass and its extract for controlling root-knot nematode,effect on tomato growth and soil environent by determination of the eupolyphaga frass ingredients and bioactive material,then through laboratory assays and pot experiments.An antagonist screened from eupolyphaga frass and the nematistatic and nematicidal activity of antagonist was assayed against the root-knot nematode,Meloidogyne incognita,Chitwood in vitro and in pot experiments.Then studied collaborative role in controlling root-knot nematodes with frass.The objective of this paper was to find the efficient utilization of eupolyphaga frass and new alternative products eventually against root-knot nematodes.The main results were as follows:1.The water content of eupolyphaga frass is 4.2%,pH 7.5 and is rich in organic matter and humic acid content,macroelement and microelements.The heavy metal content,such as cadmium,chromium,plumbum and arsenic,were significantly lower than that of national standard.The crude fiber,crude ash,crude protein content is higher.There are 18 essential amino acids in eupolyphaga frass.The ingredients analysis showed that the content of oligochitosan was about 4.4%and there were 9 categories and 110 kinds of volatile compounds in the frass.21 bacteria,6 fungi,and 4 actinomycete strains were also screened from frass.2.The results indicated that the nematode immobility and mortality was significantly increased with increasing extract concentration and treatment time.Compared with control,the egg hatching was significantly inhibited when the extract concentration was beyond 20%.The nematode immobility reached 19.5%and 36.8%,respectively after different treatments in high concentration of extract volatile 24 h and 48 h.Infection of root-knot nematodes was reduced significantly through pot experiments and field trial.The number of galls in each plant was decreased significantly with the increase of frass.The gall index(GI)was decreased significantly compared with control.Root-knot nematode and the number of eggs decreased significantly when more than 20%frass was added,total number of eggs in the egg was reduced 35.5%,embryonic egg ratio was increased,percentage of first age larva in eggs was decreased.And the number of root knot nematodes in eupolyphaga dung in the soil obviously reduced.3.The contents of chlorophyll and carotenoid,photosynthetic rate and stomatal conductance were increased in the treatment of eupolyphaga frass.The activities of protective enzymes,such as SOD,POD,APX and PAL,and root activity were also increased.The yield of each plant and area was increased,respectively.The protein and free amino acid contents increased significantly and vitamin C and soluble sugar content were higher compared with control.4.The permeability coefficient pH and EC,organic matter,nitrogen,phosphorus and potassium,the numbers of bacteria,fungi and actinomycetes were increased in soil.Using sterilized soil,we found that 20%frass can significantly promote the number of soil bacteria,fungi and actinomycetes.The activities of protease,catalase,phosphatase,urease,invertase and chitinase were also increased in soil,which are similar with microbes.5.A strain of antagonism was screened which has antagonism with root knot nematodes,Nematodes in soil was reduced 62%,galls significantly was decreased 25.5%,the female significantly was decreased 28.3%,egg mass significantly was reduced 72%compared contro through pot experiment.6.The survival rate doubled after inoculation antagonism B6 in frass.The results showed that total bacteria increased,survival rate of B6 increased by 40.3%throught pot experiment.And galls decreased significantlyand the weight of tomatoes increased compared with control,indicating that eupolyphaga frass and antagonistic bacteria have synergistic effect on the controlling of root knot nematodes in tomato.