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Influence of Relative Humidity on Pathogenicity of Metarhizium
Anisopliae Isolates from Thailand and Malaysia against Red Palm
Weevil, Rhynchophorus Ferrugineus Olivier
(Insecta: Coleoptera: Dryophthoridae)
Cheong Jia Lei
Supervisor: Prof. Madya Dr. Wahizatul Afzan binti Azmi
Bachelor of Applied Science
(Biodiversity Conservation and Management)
School of Marine and Environmental Sciences
Red palm weevil (RPW), Rhynchophorus ferrugineus, is a polyphagous insect that
caused economic damage in various palm species, particularly coconut plantation in
Malaysia. The entomopathogenicity of an indigenous (Meta-G4) and foreign (Met-TH)
Metarhizium anisopliae strains isolated from the soil of Malaysia and Thailand, were
tested against RPW adults in laboratory bioassays at 50, 70, 90% relative humidity
(RH). Laboratory results indicate no significance differences in efficacy between both
the conidia of M. anisopliae strains against RPW adults. Meta-G4 showed the highest
efficacy at 90% RH (LT50=6.17 days). However, LT50 only slightly differed from Met-
TH (6.33 days; 90% RH). Scanning electron microscopy for the treated RPWs showed
that Meta-G4 (90% RH) was densely sporulated within the abdomen, while Met-TH
can be found mainly across cuticular surface of RPW. In conclusion,
entomopathogenicity of M. anisopliae might be differed in geographical origins, while
Meta-G4 is a better biocontrol agent of RPW in Malaysia.
1685 | UMT UNDERGRADUATE RESEARCH DAY 2018