一株茶毒蛾病原细菌的分离、鉴定及致病性测定OACSTPCD

[Objective]An in vitro pathogenicity test of Euproctis pseudoconspersa,a major pest of Camellia plants,was performed to provide reference for the biological control of E.pseudoconspersa.[Method]A pathogenic bacterium strain named Nan-Y was isolated from the dead body of E.pseudoconspersa larva,and then identified by morphological observation and 16S rDNA.And its toxicity to the 4th instar larvae of E.pseudoconspersa was determined by feeding with(1.0±0.5)×1010,(1.0±0.5)×1011,(1.0±0.5)×1012,(1.0±0.5)×1013 or(1.0±0.5)×1014 cfu·mL-1 bacterial suspension.[Result]Nan-Y turned out to be Gram-negative bacteria with rod shape,and its colony on NA medium was punctiform and pale yellow with regular edge and sticky surface.Strain Nan-Y was identified as Pseudochrobactrum asacchrolyticum by 16S rDNA.The mortality of E.pseudoconspersa larvae increased with higher con-centrations of bacterial suspensions,with corrected mortality reaching 100.00%at 6 d after feeding with(1.0±0.5)×1014 cfu·mL-1 bacterial suspension.The LC50 of Nan-Y to E.pseudoconspersa larvae was 5.23×1013 and 3.04×109 cfu·mL-1 at 3 and 6 d,respec-tively.[Conclusion]Strain Nan-Y has strong pathogenicity to E.pseudoconspersa larvae,thus having application potential in the bio-logical control of the pest.