Toxicity of essential oils from plants to cacao moth, Ephestia cautella Walker (Lepidoptera: Pyralidae)

Issue Date

10-2004

Abstract

Among the biorational insecticides used against pests of stored food are botanical materials that are easily degraded and leave no toxic residues on treated commodities. The possibility of using ginger (Zingiber officinale Roscoe), neem (Azadirachta indica A. Juss.), oregano (Coleus amboinicus lour.), and castor (Ricinus communis Linn.) oils and their formulated dusts was evaluated against the larvae of E. cautella. based on the LD50, LD90, LC50 and LC90 at 48 hours after treatment, neem was the most toxic followed by oregano. Ginger was not toxic to the pest. The application of LC50's of the oils in cacao beans deterred larval feeding by 92% with neem, followed by 68% with castor oil. The highest anti-ovipository and insect growth regulatory effects were observed on castor oil treated cacao beans. Castor oil also reduced the viability of eggs by 73% and the number of eggs laid by 47%, compared to the untreated control. All the oils caused abnormalities on the larvae and pupae resulting in death. Only 10% normal adult emergence was observed for the neem-and castor oil-treated larvae and 28% for the oregano-treated larvae. All the botanical oils, except ginger, showed toxic, anti-ovipository, anti-feeding and insect growth regulatory effects on E. cautella. The effectiveness of botanical dusts in preventing or reducing damage and reproduction of E. cautella during the three month storage was significant when compared to the untreated control, indicating that these materials are promising stored product protectants. The neem, oregano and castor oil dusts could be an alternative to permethrin in protecting cacao beans against E. cautella infestation. However, there is a need to formulate and evaluate neem dust at higher concentrations.

Source or Periodical Title

Philippine Entomologist

ISSN

0048-3753

Volume

18

Issue

2

Page

177

Document Type

Article

Frequency

semi-annually

Language

English

En – AGROVOC descriptors

THEOBROMA CACAO; CADRA CAUTELLA; ZINGIBER OFFICINALE; AZADIRACHTA INDICA; COLEUS AMBOINICUS; PLANT PESTS

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