The biology and control of Liriomyza Lrifolii(Burgess) (Diptera: Agromyzidae) on tomatoes

Abstract

The study of the life history of the American serpentine leaf miner Liriomyza trifolii (Burgess) has been carried out both in the field and in the laboratory. The life cycle was found to be depenpent on temperature and relative humidity. In the field the duration was 27 days as compared to 16.4 days in the laboratory at 79+(-) 2% R.H. and 25 +(-) 1 C. Host range surveys were done at several locatio~s in the country. A total of 43 plant species in 13 plant families were found to be hosts of L. trifolii. There was a definite host preference for Compositae, Solanaceae, Cucurbitaceae and the Leguminosae families in ail the areas visited. Four indigenous agromyzid species were also found mining leaves of various host plants. Four species of parasites of L. trifolii were reared from the larvae and pupae of L. trifolii. Two species were dominant in all areas while the other two occurred in very small numbers. Six inseticides were evaluated for their effects on L. trifolii and its parasites on tomatoes. The insecticides were in two groups: Systemics and non-systemic sprays. Triazophos which was outstanding in the control of the leaf miner was found to have adverse effect on the parasites. The systemics: oxamyl and disyston were found to be ideal both for controlling L. trifolii and preserving the parasite complex. Correlation between damage caused by L. trifolii and yield was not significant. Thus, it was noted that application of insecticide treatments should relate to the marketable yield and the extent of damage in any given situation