Pathogenicity of heterorhabditis sp., an entomopathogenic nematode infecting sweet potato weevil (Cylas formicarius Fabricius)

Issue Date

10-2017

Abstract

The study aims to determine the in vitro and in vivo pathogenicity of different isolates / strains of entomopathogenic nematodes (EPN) in controlling the sweet potato weevil in the laboratory and greenhouse. There were four (4) EPN isolates used in the pathogenicity test against the larvae and pupae of sweet potato weevil namely: UBD (Bacong, Neg. Or.), AVD (Valencia, Neg. Or.), HO1 (Barili, Cebu), and CP (Pangasugan). Result of the laboratory evaluation showed that the four (4) EPN were equally promising for the control of both larvae and pupae in three (3) populations / concentrations used (100 / ml, 200 / ml, and 300 / ml.). Mortality on larvae and pupae was observed 24 hrs after treatment and 24 hrs of incubation of cadavers. A 50 % mortality of population of weevil larvae treated with the four (4) EPN was observed at a minimum of 2 days at 300 / ml populations / concentrations and a minimum of 3 days for 200 / ml and 3-4 days on 100 / ml. Fifty percent (50% mortality) of pupae was observed 5-6 days after treatment regardless of the populations / concentrations of EPN used. Percent infection on the other hand, is as high as 96% on larvae and 83% on pupae. On the other hand, three (3) of the EPN were tested against sweet potato weevil in a pot experiment using a 300 / ml population / concentration of EPN. Result showed that there is no significant difference among the three isolates in the damage rating of tubers and was found comparable to the effect of the chemicals used in the experiment suggesting their potential as biological control agents against the sweet potato weevil. Field experiment to evaluate their efficacy is underway.

Source or Periodical Title

The Philippine Entomologist

ISSN

0048-3753

Volume

31

Issue

2

Page

175-176

Document Type

Article

Frequency

semi-annually

Language

English

En – AGROVOC descriptors

IPOMOEA BATATAS; CURCULIONIDAE; CYLAS FORMICARIUS; HETERORHABDITIS; ENTOMOPHILIC NEMATODES; BIOLOGICAL CONTROL AGENTS; PATHOGENICITY; INSECT CONTROL; PEST MANAGEMENT

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