Efficacy of indigenous Beauveria bassiana and Purpureocillium lilacinum for controlling Planococcus minor (Maskell) in durian fruits

Planococcus minor (Maskell) spread in durian fields has a great impact on durian farmers. Because P. minor can damage durian at almost every stage, from fruit setting to harvest. Therefore, it is necessary to select indigenous entomopathogenic fungi that have the potential to control P. minor in durian fruits. The efficacy of indigenous B. bassiana and P. lilacinum for controlling P. minor (Maskell) in durian friuts was investigated. Insect pest samples were collected from durian orchards in three provinces: Chanthaburi, Trat, and Rayong. The collected samples were morphological identified to confirm the presence of B. bassiana and P. lilacinum. The results indicated that both spore suspension of B. bassiana and P. lilacinum at 104, 106, and 108 spore/ml were able to inhibit all growth stages of all P. minor. The concentration of 108 spore/ml resulted in the highest mortality rates for P. minor nymphs, achieving 97% and 100%, respectively. In conclusion, indigenous B. bassiana and P. lilacinum should be applied to P. minor at the nymph stage rather than during the adult stage, as the nymphs are more susceptible affected entomopathogenic fungi.