Efficacy test of some Entomopathogenic fungi to control Aphis craccivora (Koch) in yard - long bean

Abstract

The efficacy tests of 7 isolates of Metarhizium anisopliae (DOA-M1, DOA-M4, DOA-M5, DOA-M6, DOA-M7, DOA-M8 and DOA-M9), one isolate of Beauveria bassiana (DOA-B4) and one isolate of Isaria javanica (DOA-I1) against Aphis craccivora (Koch) under laboratory condition were carried out from October 2016 to March 2017. Three experiments were conducted using concentration of 1 x 108 conidia per ml. Results of the first experiment showed that DOA-M8, DOA-M9, DOA-B4 and DOA-M1 could control A. craccivora at 95.0, 87.50, 82.50 and 81.25% respectively. In the second experiment DOA-M8, DOA-M1, DOA-M9 and DOA-B4 showed the mortality rates of 95, 81.25, 81.25 and 77.50% respectively. In the third experiment, the results showed DOA-M8, DOA-M1, DOA-M9 and DOA-B4 caused 90.00, 88.75, 80.00 and 68.75% mortality rates respectively. Isolates DOA-M1, DOA-M8, DOA-M9 and DOA-B4 were chosen to study for their controlling efficacy against A. craccivora in the organic yard-long bean fields at Amphur Saiyok, Kanchanaburi province. Results of 6 field experiments showed that, DOA-M8, gave good control against A.craccivora. (79.38-96.25%), was whereas DOA-B4inferior (51.88-78.75%)Therefore Isolates M8 and B4 have the potential to be further developed into biological control agents for farmer uses in the future.