Growth and development of Leucinodes orbonalis Guenee on a modified artificial diet

Issue Date

10-2009

Abstract

Screening for varietal resistance of eggplant against its main pest, the fruit and shoot borer (Leucinodes orbonalies Guenee), needs test insects with a degree of uniformity at a given time and growth stage. For this purpose, mass rearing of the local strain of fruit and shoot borer (FSB) was attempted using beet armyworm diet modified by Talekar, Lin and Hwang (2002) with addition of eggplant powder. An initial colony collected from eggplant wilted shoots, damaged fruits, soil leaves and stems from Munoz, Nueva Ecija (Munoz city market, PhilRice central Experiment Station, PhilRice Palayamanan, Gabaldon, and Katalanacan), San Antonio, Nueva Ecija (San Francisco, Lawang, Kupang and San Mariano) and Malvar, Batangas, was established in the laboratory. eggs produced adults from these field-collected larvae were allowed to hatch and the neonates placed on the modified artificial diet. More than 50% of the larvae reared on the diet pupated but only 51% of the pupae emerged to adults because of problems such as accidental squeezing during collection process, mite infestation and presence of ants that feed on the pupae. Fifty-eight pairs of adults which emerged from the laboratory colony laid a total of 1,414 eggs with hatchability of 89.39%. Observations showed that the first instar larvae moved around the diet immediately after introduction. Afterwards, they bore through the holes provided in the diet and created tunnels within the diet as they fed. When about to pupate, the larvae escaped out of the tunnel nd pupated along the upper region of the rearing cup. It was observed that the first wave of pupation occurred at 10DAI and the pupae were mostly males, but during the peak of pupation (15-27 DAI) the sex ratio was 1:1. the latter batch of pupae (latest was at 39 DAI) again were mostly males. Data obtained from the first two generations indicated that local FSB strains can be reared successfully on the modified diet and approximately 30% of the larvae in any given batch can be expected to become adults. For continuous rearing, the number of generations without the need to renew the stock culture should be determined. Mortality rate at various stages in the rearing process was caused by inherent weakness of the population, stress due to successive transfers, larval entanglement, injury, presence of mites, ants, microorganisms, escape from rearing containers and accidental squeezing. handling of the insects and proper laboratory practices during the mass rearing process should be improved to reduce mortality of the insects being reared.

Source or Periodical Title

Philippine Entomologist

ISSN

0048-3753

Volume

23

Issue

2

Page

198-199

Document Type

Article

Frequency

semi-annually

Language

English

En – AGROVOC descriptors

LEUCINODES ORBONALIS; SOLANUM MELONGENA; EGGPLANTS; ANIMAL DEVELOPMENTAL STAGES; PEST RESISTANCE; MASS REARING

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