Manejo de biodiversidade em cultivo orgânico de alface(Lactuca sativa) através do uso de cravo-de-defunto(Tagetes erecta) como planta atrativa.

Abstract

The lettuce (Lactuca sativa L.) is the most popular vegetables, being largely cultivated and consumed in Brazil because it is source of vitamins and mineral salts, with prominence in A vitamin, presenting expressive economical importance. To minimize the problems with pests in organic lettuce, one of the main technical recommendations is the habitat diversification, which was lost or minimized due to monocultures. Is important to promote the correct diversification, using as attractive plants those that supply good resources for the natural enemies, but not for the species potentially harmful to the adjacent culture. This work had the objective of verifying the effect of marigold lines (Tagetes erecta L.) as attractive culture to natural enemies in lettuce organic fields. The experiment was accomplished in organic area in the Federal University of Lavras, settling marigold lines in a central stonemason of the main cultivation. The treatments were defined being collected the samples in the lettuce plants in the six different distances to marigold (side A) and in the control without marigold (side B). Collections of parasitic hymenoptera were also accomplished in T. erecta for analysis of its intestinal content. In a general way it was observed larger richness, diversity and natural enemies' abundance in side A, the same happening for Shannon diversity index (H’). Larger richness, diversity and abundance was found in the closest arrays of the marigold, decreasing as the stonemasons stand back. It was positive the analysis of the intestinal content of the parastitoids, having been found feeding vestiges by marigold pollen. The results obtained in this research they show that the marigold T. erecta it is a promising plant to be used as attractive in organic lettuce cultivation, since it increases the diversity, abundance and richness of useful insects, without increasing the pest problems.