Influência da interação roseira-coentro (Coriandrum sativum) – pulgão (Macrosiphum euphorbiae) (Aphididae) no comportamento de Chrysoperla externa (Chrysopidae)

Abstract

Rose bushes are one of the main cultures in Brazil and, as in every agricultural cultivation, they are also host for various pests. Among these is the aphid Macrosiphum euphorbiae, responsible for significant damage, especially due to the deformation of the sprouts. The most widely used control method for this aphid is the chemical, which causes many damages to man and to the environment. In order to avoid these problems derived from the inadequate use of these products, we must stimulate the use of biological control. The predator Chrysoperla externa is an efficient controller of many agricultural pests, among which the aphids are highlighted as their favored prey. This insect may be attracted to the interior of an agro-ecosystem by different species of company plants, being coriander (Coriandrum sativum) one of the most worldwide researched, for interfering in the behavior of the natural enemies, increasing its efficiency as a biological control. Thus, we aimed at evaluating the number of eggs produced per C. externa in rose bushes with coriander as a company plant, in regard to the presence of M. euphorbiae, as well as its olfactory response to the sources of odor of the rose bushes and coriander, influenced by M. euphorbiae. We released 80 pairs of C. externa in a greenhouse, maintained together for 10 – 12 days in order to guarantee copulation. Over the course of seven days of evaluation we counted the eggs in the rose bushes and coriander. In laboratory we evaluated the olfactory response with an olfactometer in “Y” observing the attraction of C. externa females in each arm of the device, until a maximum of 10 minutes, measuring the initial response (RI) (1st response) and the final response (RF) (permanence > 30 sec.) of each female. In the greenhouse we noted that the aphid factor presents a significant influence (P ≤ 0.05) in C. externa spawning on the rose bushes, independent of the presence or absence of the coriander. In the olfactometry studies, the C. externa females presented a significant attraction to the rose bushes infested by aphids (RI = 67% and RF = 74%), and for those not infested and having the coriander as companion plant (RI and RF = 67%). We may affirm that the presence of M. euphorbiae on the plants is a determining factor in the preference of the predator’s spawning, and it may be an adequate prey for its development and the survival of its offspring. We also noted that the coriander is an attractive plant to the C. externa due to the volatiles they exhale from the leaves, and may be useful in attracting this natural enemy of the rose bush cultivations