Comunidade de joaninhas (Coleoptera: Coccinellidae) e aspectos fitotécnicos da couve (Brassica oleraceae var. acephala) em consórcio com coentro (Coriandrum sativum), sob manejo orgânico

Abstract

The agroecological approaches of vegetable organic production presumed the design of more diversified production units over time and space, where the intercropped systems are included. One of these approaches is that the persistence, the abundance and the diversity of natural enemies that act in the insect-pest biological control are stimulated. In Brazil, despite of informal reports, such as personal communication, little has been recorded about the effects of intercropped systems in populations of insect pests and natural enemies. In this context, the present study has as objectives to determine the diversity and the community structure of the ladybirds (Coleoptera: Coccinellidae) associated with aphids in kale cultivated intercropped with coriander, and to evaluate the potential of coriander to provide the vital resources for survivor and reproduction of ladybirds, as well as evaluate the crop performance of this intercropped system, in agroecologically-based organic production system. The study was conducted in two consecutive years (2006 and 2007) in the experimental farm of integrated crop-livestock production called of Sistema Integrado de Produção Agroecológica (SIPA) or Fazendinha Agroecológica km 47, localized in the municipality of Seropedica, Rio de Janeiro, Brazil, where the experiments were carried out and involved the intercropped system of kale (Brassica oleraceae var. acephala D.C.) with coriander (Coriandrum sativum L.) in relation to kale in the monocrop system, in order to determine the diversity of ladybirds by collection of specimens through removal sampling and yellow sticky cards, as well as characterize the structure of their community by the faunistic analysis. The performance of intercropped system was also evaluated, determining the crop parameters of associated crops. A total of 25 ladybird species are present in the SIPA, but Hyperaspis (Hyperaspis) festiva Mulsant, Scymnus (Pullus) sp.3, Cycloneda sanguinea (L.) and Eriopis connexa Germar were more frequent species. There was no infestation by aphids in kale intercropped with coriander, which was used by the ladybirds as food site (resource of pollen, nectar and alternatives preys), oviposition site, refuge for larvae, pupae and adults, and mating site. As for the cropping parameters, the Land Equivalent Ratio (LER) for the intercropped system of kale with coriander, taking into account the fresh mass yield, were superior in 92% (coriander harvested with 55 days after the sowing) and 85% (coriander allowed for flowering) in relation to monocrop system. The intercropped system of kale with coriander in the arrangement of one row of kale and four paralleled rows of coriander, harvesting the two central rows at 55 days after sowing and allowed the two rows in the border of the seedbed for flowering, do not cause increases of kale yield, but was effective in respect to land effective use and as strategy of ladybirds conservation in diversified production systems.