Study On Screening Of Pesticides Against Bradysia Difformis And The Residue Analysis Of Matrine

Bradysia difformis was one of the most important pests on edible fungus in cultivation, because of its short life cycle, high reproductive rate, they could reproduce many generations in one year, and has brought a great losses to the edible mushroom industry. This research were selected some biological pesticides commonly applied, Studying on Bradysia difformis as the toxicity test research object, and the effects of pesticides on the mycelium growth of five edible fungus and control effects in mushroom house were studied by using plate method, and further study the influence on mycelium growth fruit body development and yield. The main results were shown as follows:1. Using the DNA barcode technology, amplification mitochondrial COI on larvae and adult of sciarid to identify their identity. The sciaridae and GenBank Bradysia difformis of COI sequences has99%homology, combined with the morphological identification can determine the sciaridae was Bradysia difformis Frey.2. Studying on Bradysia difformis as the research object, the laboratory toxicity was determined by mixing method, screen out effective3botanical pesticides of pyrethrin, matrine, azadirachtin, their LC50values were10.42,20.10,44.60,56.73and59.52mg/L repectively. The control effects on the adult of Bradysia difformis were tested by spray method, the result show that14mg/L azadirachtinwas has good effects, its control effect was96.48%, followed were30mg/L pyrethrins and40mg/L matrine, their control effects were95.96%and93.27%; when emamectin benzoate was50mg/L, its control effect was Similar to36mg/L abamectin, their control effects were91.49%and91.65%, respectively.3. Through plate method in laboratory, Five biological pesticides on the mycelium growth of edible fungi were studied. By comparison, Abamectin has less inhibited on mycelium, their EC50values on the mycelium for Pleurotus ostreatus, Flammulina velutiper, Coprinus comatus, Lentinula edodes was50.66,56.27,89.70and1874.86mg/L. Although they had more than50%inhibition on mycelium of azadirachtin and avermectin, but in the cultivation of Pleurotus ostreatus, their mycelium and fruiting body almost no adverse effects.4. Using the LC50of matrine, pyrethrin and azadirachtin to test their effects on Pleurotus ostreatus, and their control effects on adults in the mushroom house By spraying method, the result found that their LC50had not bad effects on Pleurotus ostreatus growth, after spaying two days,3pesticides had better control effect on the Bradysia difformis adults,20.10mg/L Matrine had best effects, its population decrease rate was83.72%, followed was10.42mg/L pyrethrins and44.60mg/L azadirachtin, the control effects was82.86%and83.11%, respectively.5.The method was established for the determination of matrine residue in compost and fruitbody of Pleurotus ostreatus by GC-NPD, Compost and fruitbody samples were vibrant extracted with acetone. These results showed that the sensitivity and precision of methods accords with demands of residue analysis of pesticide. In mix pesticide cultivation, to monitor the degradation dynamics of matrine in compost, Research shows that degradation of the pesticide with the first-order kinetics equation, and the kinetics equation was Ct=1.754e-0.06t(r=0.9510). The half life of matrine in compost was11.55d. At the same time, detect the residue of Pleurotus ostreatus in the first harvest, and the residue of matrine was not detected.