Plant Extracts and Pesticides for the management of the American Serpentine Leafminer (Liriomyza trifolii)

Abstract

Pesticides have been the most common method for management in the control of Liriomyza trifolli. However, some plants produce substracts with pesticide potential and could be used for the management of this pest. Therefore, the aim of this study was to assess the pesticide potential of tobacco, pepper, castor beans, and garlic extracts in the management of L. trifolli, comparing them to commercial pesticides (Milbeknock® and Vertimec®). The extracts were tested at a concentration of 2.5 mL/100mL of water and pesticides in the concentrations recommended by the manufacturer. The extracts were applied to 10 tomato plants (50 days after sowing), previously submitted to an infestation of L. trifolli for 4 hours. The assessments were initiated one day after pulverization, counting the presence of miners in the leaves, number of alive and dead larvae and the viability of pupae. To assess the effects of the extracts and the pesticides on larval phase, tomato plants with the same characteristics of the previous experiment were submitted to an infestation of the pest for 4 hours. After 72 hours, the extracts and pesticides were pulverized at its respective concentrations. The larval, pupae, and total mortality data were subject to variance analysis, regression, and means were compared by Tukey test at 5% probability. It was found that the pesticide Vertimec® was efficient in the management of L. trifolli both when applied over eggs and larvae. However, among the tested extracts, the garlic extract was more efficient on eggs and larvae, becoming a promising and viable alternative to the management of L. trifolli.