POTENTIAL OF ENTOMOPATHOGENIC NEMATODE ISOLATES AS BIOLOGICAL CONTROL AGENTS AGAINST THE SWEETPOTATO WEEVIL Cylas formicarius Fabricius (COLEOPTERA: Brentidae)

Sweetpotato weevil (Cylas formicarius F.) is one of the threats of sweetpotatoes in the Philippines. Controlling this pest is important to increase the production of sweetpotatoes. Therefore, a study was conducted to determine the virulence of four local Heterorhabditis indica (MBC, ZBC, GBC and VSU) isolates against the different stages of sweetpotato weevil, Cylas formicarius Fabricius (Coleoptera: Brentidae), evaluated under laboratory conditions. The four EPN isolates being tested in this study revealed that they have the potential to act as biological control agents against Cylas formicarius. The highest percentage mortality was obtained by the MBC isolate with 80.53% and 82.09% in the larval and pupal stage, respectively. On the other hand, the ZBC isolate obtained the highest percentage mortality of 32.76% in the adult stage. Regardless of the EPN concentrations and exposure to time, all of the four isolates were not statistically different.