NÍVEL DE DANO ECONÔMICO PARA INSETOS DESFOLHADORES EM FEIJÃO-CAUPI

Abstract

The cowpea bean (Vigna unguiculata (L.) Walp.) is often attacked by defoliator insects. There are a great number of species of these defoliator insects and they cause huge damage to the plants. The most important being: Diabrotica speciosa e Cerotoma arcuata (both Coleóptera), Spodoptera frugiperda, Mocis latipes e Spodoptera cosmioides (both Lepidoptera). Understanding the relationship between the plague infestation and the productivity of the culture is one of the keys to the success of the integrate management of the cowpea bean. Studying the artificial defoliation process in order to simulate similar insect damages to the plants is useful. There are few research studies about the artificial defoliation in the cowpea bean plant. So, this study was developed to determine the level of economical damage inflicted by defoliator insects in cowpea bean plants in the Cultivar BR-17 Gurguéia. The experiments were conducted in the do Departamento de Fitotecnia do Centro de Ciências Agrárias da Universidade Federal do Piauí. The defoliation were in the order of 0%; 25%; 50%; 75% and 100%. The experiment was taken 25 days and 40 days after planting the cowpea bean plants. The production loss threshold of the cowpea bean in local condition in Teresina-PI is R$ 61.00.ha-1, which allows, through regression analysis, the following conclusion: the level of control of defoliator insects during the vegetative state is about 60% of defoliation; while in the reproductive state it is about 47%.