INTEGRATED PEST MANAGEMENT FOR PROCESSING TOMATOES IN THE EBRO DELTA (SPAIN)

To design an Integrated Pest Management Program, the efficacy of Bacillus thuringiensis applications according to a threshold for Helicoverpa armigera was assessed, and the secondary pests of the crop were determined. Four fields in 1996 and five fields in 1997 were monitored.H. armigera eggs and larvae were counted in the leaf below the highest open flower. Fields were sprayed with B. thuringiensis when the number of eggs and larvae per leaf was higher than 0.04. Other pests and natural enemies present in the foliage, and percentage of fruits injured by lepidoptera were also recorded.

Our results suggest that B. thuringiensis treatments applied according to the proposed threshold may keep the percentage of fruits injured by H. armigera to 3% or less. To achieve pest control, the timing and the uniformity of distribution of the spray are critical. Chrysodeixis chalcites and Macrosiphum euphorbiae were present in all the fields, but no damage was registered. Aphid parasitoids and Aphidoletes sp. larvae were abundant and kept the pest below damaging level. No parasitized lepidoptera eggs or larvae were observed in field scoutings. Whiteflies, thrips, leafminers and mites were present in some fields but no damages due to these pests were recorded. Polyphagous predators such as mirid and minute pirate bugs, lacewings, syrphid flies and lady beetles were also observed in the fields but their impact on the pests was not evaluated.

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