Impact of thrips tabaci lind. on onion yield and its chemical control [electronic resource].

Includes references.

Onion thrips, Thrips tabaci Lind. (Thirpidae: Thysanoptera) severely attack onion plants with high population density from seedling stage until harvest. In recent years, onion Allium cepa has become one of the important export crops in Egypt; cultivated in different regions in large areas for bulb yield, as well as green onion use. Thrips not only scrawl plant tissue and suck plant juice causing white spots that deform green onions and reduce onion bulb yield, but also wounds caused by thrips feeding allow entry and development of fungal diseases (McKenzie et al, 1993). High thrips populations cause up to 40% loss in onion yield (Sato and Nakano 1990; Domiciano et al. 1993; Fournier et al. 1995 and Jensen et al. 2003). The present work aims to evaluate the effects of thrips infestation on the yield of onion bulbs and also the impact of repeated applications of chemicals on thrips population and on yield and therefore to determine the number of sprays required to keep population of this pest under economic threshold.

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