Chemical Control of Nematodes and Insects in Tomato

Abstract

The effectiveness of four nematicide-insecticides and three insecticides for the control of the reniform nematode (Rotylenchulus reniformis), vegetable leafminer (Lyriomyza sativae), and white grubs (Phyllophaga spp.) on tomatoes (Lycopersicon esculentum), was determined in three field experiments established in 1980 and 1981 at lsabela, Puerto Rico. In the first test permethrin, oxamyl and metamidophos effectively controlled leafminer. Acephate provided moderate control, whereas carbofuran and aldicarb were ineffective. All nematicide-insecticides were effective in the control of R. reniformis in the soil. In the second test, lowest populations of white grubs were collected from plots treated with carbofuran and aldicarb, followed by those treated with oxamyl. In the third test there was a significant decrease of leaf-miner population in carbofuran- and permethrin-treated plots. A reduction of leafminer infestation was also obtained with aldicarb, pydrin and methamidophos. Significant yield increases were obtained from plots treated with both doses of acephate, permethrin, metamidophos and pydrin. Even though a nematode control over 60% was obtained in all treatments, yields from plots treated with nematicides were similar to that from the control, suggesting that yield increases cannot be attributed to insect control or nematode control only, but to the effect of these pesticides on unknown factors in the plant. No phytotoxicity was observed with any of the pesticides in any of the tests.