Controle químico e distribuição espacial de ninfas de Quesada gigas Olivier (Hemiptera: Cicadidae) em plantios de paricá em Dom Eliseu, PA.

Abstract

The paricá [Schizolobium parahyba var. amazonicum (Huber ex Ducke) Barneby, Leguminosae: Caesalpinioideae] is essentially a native forest in the Amazon region, however, the dispersal of species through crops in northeast and southeast of Pará State, have provided additional insect-plant interactions as the attack cicada Quesada gigas causing a lot of damage to the plant and the local timber industry with losses of up to 20% of the planted areas. This work is divided into two chapters, the first aimed to determine the more efficient and economically viable dosage of chemical insecticide to control Quesada gigas (Hemiptera: Cicadidae) nymphs in parica plantations. Three dosages of three products (carbofuran, imidacloprid and thiamethoxam) were tested based on the maximum recommended dosage for the control of cicadas in coffee plants and applied in total area. The dosage of one kilogram of a commercial product based in thiamethoxam per hectare was more efficient economically and environmentally to control nymphs of Q. gigas in parica plantations. The second chapter aims to determine the spatial distribution of Quesada gigas nymphs in parica plantations as well as the developmental stages most commonly encountered and the galleries depths of the nymphs in the soil. Two plots were selected depending on the intensity of damage with more and less visible damages. In each an area 10 x 12 m subdivided into quadrats of a square meter was chosen randomly. In these quadrats were counted nymphs, galleries and their distances from the axes (X and Y) of the quadrants and the depth (Z) of the galleries. An approach of spatial distribution was performed with indexes variance/mean. The nymphs of Q. gigas have gregarious habits not necessarily around the attacked tree, the nymphs of the fourth and fifth instars were found more commonly and the depth of the galleries ranged from eight to thirty-five centimeters regardless of the attack intensities.