Local de oviposição, tempo de penetração, efeito de inseticidas e parasitoides larvais associados à Grapholita molesta (Busck, 1916) (Lepidoptera: Tortricidae) em macieira e pessegueiro.

Abstract

The oriental fruit moth Grapholita molesta is one of the main pests of the apple and peach trees. This work aimed to evaluate the preference of oviposition of G. molesta at different phenological stages of apple and peach trees, the penetration time of the caterpillars at different vegetative structures (fruits and tops), the efficiency of insecticides for pest control at different stages of development of the insect, and inventory of parasitic larval species of G. molesta at different producing areas. The apple and peach trees leaves were the favorite oviposition sites for G. molesta adults. However, 7.7% of the laying was recorded in apple fruits during maturation, while oviposition rarely occurs in this plant structure in peaches. The mean time spent by 90% of the caterpillars to penetrate the vegetable structures (TM90) was shorter in the peach tree tops (3.25±0.51 hours) than in fruits (6.7±0.95 hours), different from the apple tree, which presented longer TM90 in tops (5.23±1.29 hours), when compared with fruits (2.67±0.6 hours). In apple fruits the peduncle (65%) and the calyx (35%) were de sites of higher penetration. In peach fruits the caterpillars penetrate the side region and the peduncle, with 62% and 38%, respectively. The insecticides acetamiprid, phosmet, spinetoram and novalurom reduced hatching in levels above 80%, regardless of whether the application is performed before or after oviposition. The etofenprox was most effective when applied after oviposition. In apple and peach tops, the insecticides acetamiprid, chlorantraniliprole, etofenprox, phosmet, novalurom and spinetoram caused mortality of caterpillars over 90%. In apple fruits, the insecticides acetamiprid, chlorantraniliprole, etofenprox, phosmet, and spinetoram, caused 100, 79, 76, 97 and 100% mortality, respectively, whereas in peach fruits this control was over 85%. The insecticide novalurom caused lower mortality of caterpillars when applied on fruits, compared to the application on tops. In adults, only the insecticides etofenprox and phosmet were toxic both to females (59% and 39%) and males (79% and 80%), while spinetoram was effective only in males (78). In peach tree, the average parasitism level in caterpillars collected at field was of 72%, and the species found were identified as belonging to the species Hymenochaonia delicata (92.81%), Temelucha sp. (2.67%), Pristomerus sp. 1. (0.12%), Pristomerus sp. 2. (1.16%), Xiphosomella sp. (3.02%), and Lycorina sp. (0.12%). It is concluded that Grapholita molesta prefer to lay their eggs on leaves, and the penetration of caterpillars is faster in apple fruits and peach tree tops; the insecticides etofenprox, phosmet and 10 spinetoram were efficient in the control of G. molesta in all stages of development. The parasitoid Hymenochaonia delicata was the most found species in peach orchards.