Collection, identification, evaluation and culture of natural enemy of the abaca corn weevil.
1994
Milan P.P. | Alcahal B.D. Jr.
A survey was conducted in selected areas of Leyte and two fungal pathogens were isolated from dead corn weevils collected from Sogod and ViSCA, [Visayas State Coll. of Agriculture, Baybay, Leyte, Philippines]. Evaluation showed that the ViSCA isolate was more effective compared with the Sogod isolate using spraying and dipping methods. Another four fungal pathogens were isolated from the dead corn weevil collected from Abuyog, Bontoc, Mahaplag, and Maasin and the isolates were identified as Metarhizium sp. Among the 10 local substrates tested for metarhizium production, corn grain was found best with the highest spore concentration counted per ml which was comparable to PDA check. The LC/LD50 of this natural enemy was 1.0 x 10 to the seventh power spores/ml based on the pathogenicity test conducted in the laboratory. In pot experiment, spore plus substrate was found better than spore suspension alone with 53-71 and 32-31 percent infection, respectively, The efficacy of the fungus (ViSCA isolate) was tested in five sites of Leyte namely: Abuyog, Mahaplag, Maasin and ViSCA (with 2 sites, A and B). Infection rate of Metarhizium sp. (ViSCA isolate) against the abaca corn weevil ranges from 34-79 percent.
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