Ovipositional preference of Trathala flavoorbitalis Cameron (Hymenoptera: Ichneumonidae), a larval parasitoid of eggplant fruit and shoot borer, Leucinodes orbonalis Guenee

Issue Date

10-2009

Abstract

Ovipositional preference of Trathala flavoorbitalis Cameron (Hymenoptera: Ichneumonidae) for larvae of eggplant fruit and shoot borer, (EFSB), leucinodes orbonalis Guenee (Lepidoptera: Pyralidae), was determined in the laboratory. Given free choice, first and second instar larvae were not selected by T. flavoorbitalis for oviposition but host mutilation was apparent. Third and fourth instar larvae were more preferred. Given no choice, third and fourth instar larvae got highly parasitized. Females more readily oviposited in borer larvae with fresh fecal matter. Field parasitism in different sampling areas ranged from 16.70 to 25.88% with an average of 21.97%. Higher parasitism was recorded on eggplant borer larvae collected from the fruits (19.35%) compared to larvae collected from the shoots (12.28%). Other larval parasitoids that emerged included a Scelionid wasp and Cotesia sp. Cocoon of unparasitized eggplant borer larva was significantly bigger than that of parasitized borer. Results of laboratory test showed an average of 15.98% larval parasitism. Life cycle of T. flavoorbitalis from oviposition to parasitoid emergence was about 20-24 days. It passes through three larval instars. Adult longevity was shortened (2.82 ± 0.85 days) when the insect was not provided with food. When fed with honey, T. flavoorbitalis adult lived for 9.64 ± 2.46 days. Multiple stinging of the host larva is one of the characteristics of the parasitoid, which does nor necessarily lead to parasitoid development but results in death of the host larva, thus can help regulate EFSB population. No parasitoid was observed in the reported alternate host Crocidolomia pavonana (Zeller).Successful parasitism on EFSB in the absence of male in the laboratory confirms that this parasitoid is parthenogenetically thelytokous. All the 507 parasitoids that emerged from field-collected parasitized EFSB larvae were females. This parasitoids could be a promising biological control agent against EFSB since it is parthenogenetically thelytokous, can be reared in the laboratory, and with satisfactory levels of field parasitism.

Source or Periodical Title

Philippine Entomologist

ISSN

0048-3753

Volume

23

Issue

2

Page

131-148

Document Type

Article

Frequency

semi-annually

Physical Description

tables; illustrations

Language

English

En – AGROVOC descriptors

LEUCINODES ORBONALIS; ICHNEUMONIDAE; EGGPLANTS; OVIPOSITION; PARASITOIDS; PARASITISM

This document is currently not available here.

Share

COinS