Occurrence of Insect Pests in a Tomato Field under a Pesticide-free Dry Season Water-saving Cultivation in Northeast Thailand

The occurrence of insect pests and natural enemies was surveyed in a tomato field subject to water-saving cultivation during the dry season in northeast Thailand. The water-saving cultivation plots were mulched with plastic film or rice straw and watered 5 times during the crop cycle, while the conventional plots were un-mulched and watered 3 times a week. A total of 5 g.m(-2) of 12-9-6 liquid fertilizer was applied to each plot. Pesticide was not applied to any of the plots. The tomato yields in the plots covered with plastic film or rice straw mulches were 1205 and 934 gm(-2), respectively, and that of the conventional plot was 1123 gm(-2). These values were almost similar to the local average yield of 1190 g.m(-2). The prevalence of various insect pests such as aphid, thrips, whitefly, leaf miner, insects belonging to the Coccidae and Miridae families, and cotton bollworm were observed. The water-saving cultivation had little influence on the occurrence of insect pests compared with conventional cultivation. Apart from some yield loss due to the cotton bollworm, the tomato yield remained nearly intact, and the crops sustained no serious damage.