花生播种期施用绿僵菌防治蛴螬的研究

Biocontrol of Peanut White Grubs,Holotrichia parallela,Using Entomopathogenic Fungus Metarhizium anisopliae at Sowing Period of Peanut

本文研究金龟子绿僵菌Metarhizium anisopliae M202-1菌株对花生蛴螬的防治效果。室内生物测定表明,在含有绿僵菌5×106、10×106和20×106孢子?g?1土壤中,暗黑鳃金龟Holotrichia parallela幼虫死亡率分别为22.4%、41.1%和74.4%,高浓度下LT50为11.9d。盆栽试验中,在播种花生时进行土壤施菌、施药处理,并在花生开花时进行接虫对比处理,结果显示:对照土壤中接虫处理的蛴螬为害可造成花生好果数减少29.2%,果重减轻26.1%,虫果增加率达28.1%;土壤施菌后接虫条件下虫果增加率为20.7%,比对照减少7.4%;但不论接虫与否,花生好果数及果重与对照土壤不接虫处理的差异均不显著;辛硫磷处理对蛴螬有较好的直接控制作用,但使花生结荚数减少;1/2剂量绿僵菌加1/2剂量辛硫磷混合处理不能很好控制虫害。田间试验显示,播种时绿僵菌能有效控制蛴螬为害,收获期花生的好果数和果重都提高40%左右,显著高于对照,虫果率降低10.9%;绿僵菌的防治效果显著高于辛硫磷。

Entomopathogenic fungus Metarhizium anisopliae M202-1 was studied as a biocontrol agent against peanut white grubs. Bioassay in lab showed that the mortality of the white grubs Holotrichia parallela at the densities of 5× 106, 10×106 and 20× 106 conidia.g-1 in soil were 22.4%, 41.1% and 74.4%. The LTs0 value at high density was 11.9 d. Treatments in pot experiment included soils added the fungus or chemical phoxim, and handled with or without white grubs at flowering period. Results showed that the number and weight of peanut pods in control soil with grubs were reduced 29.2% and 26.1% compared to those without grubs, respectively. Peanut pods were damaged 28.1% in the pots with grubs. The Metarhizium treatment could avoid 7.4% pods damaged compared to control when handling with grubs; but there was no significant difference in the number and weight of peanut pods between the fimgal treatment and control soil without grubs. Phoxim could effectively control grubs but caused less pods. Half dosage of the fungus adding half dosage of phoxim could not keep grub harm down. Field assay indicated that the fungus treatment at seeding time could effectively depress harm by white grubs, increase about 40% of the number and weight of peanut pods and reduce 10.9% pods damaged in comparison with control based on harvest survey, obviously superior to phoxim treatment.