Efficacy of insecticides on Leptopharsa gibbicarina Froeschner (Hemiptera: Tingidae) applied by root absorption technique in oil palm.

Leptopharsa gibbicarina Froeschner (Hemiptera: Tingidae) a pest and vector of Pestalotiopsis in oil palm (Elaeis guineensis Jacquin) in America. The objective of this study was to determine the efficacy of insecticides on L. gibbicarina for root absorption technique as an alternative to the use of monocrotophos. This study was done in oil palm plantations in the municipality of Puerto Wilches, Santander, Colombia. Eight systemic insecticides were selected by the absorption capacity in oil palm roots, mortality on L. gibbicarina and long time protection. The root absorption capacity of insecticides was evaluated applied in volumes of 10 ml per 48 hours. Concentrations of insecticides were applied by root absorption to determine the toxicity L. gibbicarina. Long time protection of insecticides on populations of L. gibbicarina was determined. Lambdacyhalotrin, methamidophos, thiametoxam were absorbed by the plant to different volumes, compared with monocrotophos (F1,48 = 58.15, P < 0.05). Lethal effect caused by lambdacyhalotrin, methamidophos, monocrotophos and thiametoxam on L. gibbicarina was obtained with concentrations500 ml -1 y 600 ml -1 (F1,19 = 11.76, P < 0.05). Long time protection of insecticides was 20, 22, 37 and 40 d by thiametoxam, lambdacyhalotrin, monocrotophos and methamidophos, respectively. The effectiveness of its insecticides for root absorption technique may be explained to the chemical formulation, plant physiology, and toxicity on L. gibbicarina. Systemic insecticides absorbed by the plant, with lethal effect on L. gibbicarina alternative should be used at populations control in oil palm.