Isolation and identification of the insect pathogenic fungus Beauveria asiatica and its pathogenicity tocopper-green chafer Anomala corpulenta larvae
To identify highly pathogenic strains against copper-green chafer Anomala corpulenta larvae,entomopathogenic fungi were isolated and cultured from naturally infected A.corpulenta in the peanut field.Strain identification was based on morphological characteristics and phylogenetic analysis of the ITS and EF1-α regions of rDNA.The biological characteristics and pathogenicity of the isolated strain were compared with known strains.The strain's efficacy was tested under various spore concentrations,temperatures,and humidity levels to determine the optimal conditions for larval control.The results identified a strain named BaT as Beauveria asiatica based on morphological and molecular analysis.The daily growth rate of BaT was 3.49 mm/d under constant temperature and illumination,which was significantly lower than that of Metarhizium anisopliae Ma26(5.15 mm/d)but significantl higher than that of B.assiana Bb58,Bb31,and Bb48(3.11-3.34 mm/d).On the 15th day,the spore production rate of BaT was 6.02× 107 spores/cm2,lower than strains Bb58,Bb31,and Bb48 but significantl higher than Ma26.The spore germination rate of BaT reached 96.22％within 12 hours,with no significant differ-ence compared to the other four strains.Under the same infection conditions,the mortality rate of BaT-infected larvae increased over time and was significantly higher than that of the other four strains on the 15th day.At a concentration of 1×108 spores/g over 19 days,BaT achieved a corrected mortality rate of 79.42％,significantly higher than other concentrations tested.The LC50 of BaT for 2nd instar larvae of A.corpulenta was 2.01×107 spores/g.The optimum temperature range for BaT infection was 20-30 ℃,with 25 ℃ being the most effective.The optimal humidity was[80％-90％).These results indicate that BaT could be an effective agent for the biocontrol of A.corpulenta larvae.
Anomala corpulentaBeauveria asiaticaisolation and identificationbiological character-isticspathogenicitybiological control
万方数据
维普
