Evaluación de diferentes dosis y métodos de aplicación de insecticidas sistémicos para el control del minador de la hoja de los cítricos Phyllocnistis citrella Stainton en plantas de limonero

the citrus leafminer, phyllocnistis citrella stainton, affects lemon flushes severely, producing direct damages from december to march. winding mines allow pathogens to access the plant, causing indirect damages. young plants are the most affected. several chemical products sprayed on citrus foliage are used to control citrus leafminer, but control period is very short. thus frequent sprays are required to control the pest effectively. the aim of these trials was to evaluate the efficiency of imidacloprid and thiametoxam applied at different doses on citrus trunk and soil. two imidacloprid formulations applied on soil and trunk were tested at doses ranging from 0.1 to 0.7 g a.i./cm of trunk diameter. thiamethoxam at 0.25 g a.i./cm of trunk diameter doses was only tested in soil applications (drench). leaves with p. citrella active mines were counted for treatment evaluations and leaf damaged area was subsequently estimated. all treatments controlled the pest. higher control levels were obtained with doses of 0.25, 0.35 and 0.7 g a.i. of imidacloprid and 0.25 g i.a. of thiamethoxam applied by drench on three-year-old plants. a hundred days after treatments were applied, leaf damage in these plants was lower than 2%. imidacloprid applied at 0.35 and 0.70 g a.i. were the only treatments that maintained these control levels in four-year-old plants. trunk treatments showed less residual effect and higher leaf damage than treatments applied by drench.