The Establishment and Impact of the Parasitoid (Diadegma semiclausum and Cotesia plutellae) Releases in the Management of Diamondback Moth of Crucifiers

Professorial Chair Lecture

Inaugural Professional Chair Lecture, Central Bank Professional Chair

Place

IBS Building, Department of Entomology, College of Agriculture, UPLB, College, Laguna

Date

6-26-2001

Abstract

Two larval parasitoids, Diadegma semiclausum Hellen and Cotesia plutellae (Kurdj) were introduced into the Philippines in 1989 for the management of diamondback moth (DBM), Plutella xylostella L., a very destructive insect pests of Brassica crops worldwide. The parasitoids were imported by the Dept. o Entomology, CA, UPLB from the Asian Vegetable Research and Development Center (AVRDC, Taiwan) through the Asian Vegetable Network (AVNET) a collaborative project with Taiwan, Indonesia, Malaysia and Thailand. Diadegma is suited for high elevation (>800m above sea level [ASL]) and temperature range of 10-24°C while Cotesia is suited for lowland elevation (800m or below ASL) and temperature range of 25°C - 30°C. Thus, Diadegma and Cotesia were mass-reared, evaulated piloted and promoted in the highland by Prof. Cardona of Benguet State University (BSU) and in the lowland by the author, respectively from August 1989 to 1996.

The initial field releases of Diadegma in 1990 as core component of the IPM for DBM, markedly reduced the DBM population in crucifier growing area of Atok to 0.4 to 2.8 larvae compared to 4-10 larvae before the releases. The monitoring of the DBM population and the parasitism three years (1995) and nine years (2001) after the last releases of Diadegma in Benguet and Mt. Province showed that Diadegma is established in these areas. This is manifested by the high rate of parasitism (49% to 80%) resulting to less than one larvae/plant.

Likewise, Cotesia is established in Nagcarlan and Liliw (Laguna) and Dolores and Sariaya (Quezon) as shown by the low DBM larvae of less than 2/plant and high rate of parasitism of 52% to 93% nine years after the last release of the parasitoid in 1992.

The adoption of the parasitoid-based IPM technology for DBM with the concomitant establishment of Diadegma and Cotesia has produced many benefits. These include: increase yield and income up to 75%; reduced cost of production and pesticide application up to 41% and 80% respectively; enormously savings in dollar reserves (US $4.52 M yearly) from pesticide imports, reduced environmental pollution and conservation of beneficial arthropods.

The more than eleven years of piloting and monitoring clearly indicated that the farmers are convinced of the benefits derived from the parasitoid-based IPM technology for DBM. However, in some areas especially in the lowland elevation, Cotesia failed to establish either due to discontinuation of the farmer participated demo farm because of the absence of trained worker or technician to assist the farmers in the piloting or no Cotesia coccons could be supplied to the farmers for the next cropping season as experience in Ilocos Sur and Norte. The government through certain institutions/agencies should provide sufficient logistic support for the mass-rearing of the parasitoid not only for supplies and infrastructure needs but for developing the required human resources (i.e. entomologists). Furthermore, there should be a sustainable support for the national government in transferring the technology to the farmers (trained technicians, vehicles, materials for training, etc.)

Some pests have become important as a result of effective DBM control like the cabbage moth, Crocidolomia binotalis, Hellula sp., Spodoptera litura, whiteflies, leafminers, and aphids. Research on the development of a biological control-based IPM for these pests should be supported by the national government and/or through linkages with external organizations.

Location

UPLB Main Library Special Collections Section (USCS)

College

College of Agriculture and Food Science (CAFS)

Language

English

This document is currently not available here.

Share

COinS