Effect of nitrogen and free amino acids on populations of thrips (Insecta: Thysanoptera) in french bean (Phaseolus vulgaris L.)

Abstract

Thrips (Insecta:Thysanoptera) are pests that affect ejote francés (Phaseolus vulgaris L.) there are agronomic practices that favor the increase of insect populations, such as fertilization. The objective of the research was to establish the effect of nitrogenous fertilizers and free amino acids in different concentrations on the populations of trips of the species Frankliniella occidentalis (Pergande) and Trips tabaci (Lindeman), in the cultivation of French beans. Nine plots were established, three concentrations of nitrogen fertilizers (urea 46 %) (71 kg ha^-1, 95 kg ha^-1 y 119 kg ha^-1) and organic fertilizer (compost) (3 825 kg ha^-1, 5 100 kg ha^-1 y 6 375 kg ha^-1), three concentrations of free amino acids (0.75 L ha^-1, 1 L ha^-1, 1.25 L ha^-1) were evaluated. response variables were: number of adults and nymphs/plant and number of adults and nymphs in each phase of plant development. The concentrations of the recommended dose for urea nitrogen of 95 kg ha^-1 and 119 kg ha-1 and free amino acids of 1 L ha^-1 and 1.25 L ha^-1 had a positive effect on thrips populations in the nymphal stage and adults (p = < 0.0001), mainly in the production phase of the crop, which indicates the importance of correct management of these fertilizers in the cultivation of French beans to avoid favoring the increase of thrips populations.