XA9951613

FAO/IAEA Int. Conf. on Area-Wide D-01 Control of Pests, Penang, May 28 to June 2,1998

INTEGRATED CONTROL OF THE , PLUTELLA XYLOSTELLA (L.) IN MAURITIUS Deovruth Abeeluck and Chandramohun Dunhawoor Ministry of Agriculture and Natural Resources, Entomology Division Jieduit, Mauritius

The diamondback moth (DBM), Plutella xylostella is a major pest of cabbage and cauliflower in Mauritius and has been successfully controlled with synthetic until 1980. In 1985, most insecticides became ineffective against this pest and farmers increased dosages and frequencies of applications and even used mixtures of insecticides to achieve synergistic effects.

The Integrated Pest Management (IPM) programme was initiated with the support of the International Atomic Energy Agency (IAEA) to develop environmentally safe control measures that could be integrated and recommended as an IPM package to farmers to reduce the pesticide load on these crops. Research was directed towards the development of a biological control programme, an action-threshold to treat on a need basis and Fl sterility technique. The efficacy of biopesticide () was evaluated. Research activities were undertaken in a logical and sequential process to assure the successful implementation of this project

In 1991, two exotic parasitoids, Cotesia plutellae Kurdjumov and semiclausum Hellen were introduced from Taiwan. C. plutellae became well established in crucifer growing areas and parasitism up to 96% was recorded in 1994. Farmers were advised to apply insecticides only when they recorded an average of 0.5 per plant from 20 plants selected at random from a cabbage plot. Marketed strains of 5. thuringiensis (Dipel, Xentari and Turex) were tested against P. xylostella under laboratory and field conditions and were found effective.

In 1997, crucifer growers were trained on the IPM approach for the control of P. xylostella and for the implementation of a biopestkide-IPM system. Tests to control the pest by the innoculative release of C. plutellae and judicious use of biopesticide were conducted successfully in farmers' fields. The use of Indian Mustard as a trap crop for DBM was conducted. Under laboratory conditions, virgin females, when exposed to Indian Mustard and cabbage plants, laid higher numbers of eggs on the former. Dosimetry tests were conducted and 150 Gy was found appropriate for use in the Fl sterility programme. DBM has been reared on artificial diet with little success. Larvae hatching from eggs laid from DBM raised from larvae and pupae collected from field do not readily accept the artificial diet. A number of generations are required to select a DBM population that will readily feed on the artificial diet. A continuous rearing of DBM on artificial diet is pursued for the Fl sterility programme and mass rearing of C. plutellae.

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