EFFECT OF INSECTICIDE TREATMENTS TO REDUCE INFESTATION BY CITRUS THRIPS (THYSANOPTERA, THRIPIDAE) ON GROWTH OF NONBEARING CITRUS

We assessed the value of chemical control used to protect young orange trees from foliar damage caused by citrus thrips, Scirtothrips citri (Moulton). As many as 17 insecticide applications to individual navel orange, Citrus sinensis L. Osbeck, trees during the first 3 yr after p lanting failed to result in an increase in tree size during years 2 th rough 5 or yield during years 3 through 5. Similarly, 19 applications to 0.44-ha blocks of 'Valencia' oranges during the first 3 yr after pl anting failed to result in increases in trunk circumference during yea rs 1 through 4 or yield in the first 2 yr of fruit production. In cont rast to the practice of many growers, we suggest that intensive contro l of citrus thrips populations on young, nonbearing trees is not warra nted and could lead to increased problems with citrus thrips resistanc e to the limited number of available and effective insecticides.