Influência do sistema de plantio na comunidade de artrópodes associados às culturas do feijão e mandioca

Abstract

In Brazil, the beans Phaseolus vulgaris (Linnaeus) and cassava Manihot esculenta (Crantz) are grown in monoculture or intercrop systems. Despite the advantages that the intercrop offers as: the intensive uses of the area, protection against soil erosion, reduction in pest attack, studies have shown the impact of inadequate management on the biodiversity in agroecosystems. This study aimed to evaluate the effects of planting system adopted in the arid zone meridional of Pernambuco, on the canopy arthropod community associated with common bean and cassava. The research was conducted in commercial fields in the region in three treatments: 1) bean monoculture, 2) consortium bean-cassava, 3) cassava monoculture. Were delimited four plots of 15 x 15m, for sampling by direct observation of insects in the canopy five plants per plot, twice weekly from May to July 2009. The species that best explained the variance observed weresubjected to Canonical Variate Analysis (CVA) and Repeated Measurements. The analysis showed differences between treatments on the composition and frequency of species. The species that contributed most to the difference between the treatments were: Urbanus proteus (L.), Aphididae sp6, Empoasca kraemeri (Ross & Moore), Aphididae sp1, Diabrotica speciosa(Germar), Aphididae sp2, Staphylinidae sp2, Lampyridae sp1, Pieridae sp1 and Thripidae sp1. The interactions between treatments and time were significant for eight of the 15 species analyzed. The herbivores were predominant in all treatments. The greater number of herbivores in the consortium may have been favored by management and by climatic factors. It can be concluded that the terms of the Arid Zone Meridional of Pernambuco, the intercropping system (Bean with cassava) favored the increased pressure of herbivory in the agroecosystem.