Dinâmica populacional do bicho-mineiro e de seus inimigos naturais em cafeeiros orgânico e convencional adensados

Abstract

The present research was carried out in a two planting fields of 2.0 ha of coffee crops under dense plantation (2.00 x 1.00 m), cultivar of Acaiá/IAC-474-19 : one under organic crop and the other in conventional crop, with five years of age, in Santo Antônio do Amparo, State of Minas Gerais, Brazil. The population dynamics of the coffee leaf-miner Leucoptera coffeella (Guérin-Mèneville & Perrottet, 1842) (Lepidoptera: Lyonetiidae) and its natural enemies were studied. The percentage of mined leaves, mines preyed by wasps, the number of live caterpillars of the coffee leaf-miners, the number of pupae in sixty leaves collected in the sample and total percentage of parasitism were assessed. The data referring to each assessment and crop system were submitted to the variance analysis and to the grouped means test of Scott & Knott (p≤0.05). It was observed in 1999 that the organic coffee crop showed a higher percentage of leaves mined by the coffee leaf-miner (45.3%), mines preyed by wasps (8.0%), a higher number of live caterpillars and pupae, and a higher percentage of total parasitism (65.5%), in relation to the conventional crop system (11.2% of mined leaves and 36.1% of total parasitism). This situation was inverted for the percentage of mined leaves and the number of live caterpillars in 2000 and 2001. No egg parasitoids of the coffee leaf-miner were detected in any of the crop systems. The most abundant species of larval parasitoids were Orgilus niger, Centistidea striata, Stiropius reticulatus (Hymenoptera: Braconidae) and Horismenus sp. (Hymenoptera: Eulophidae).