FLORES DE ALISSO ASSOCIADAS A CULTIVOS DE COUVE VIABILIZAM A ATRAÇÃO DE INIMIGOS NATURAIS E O MANEJO DE INSETOR-PRAGA

Abstract

Collards (Brassica oleracea (L.) var. Acephala) are often attacked by various pests such as whiteflies, aphids, cabbage leafworm, diamondback moth, Ascia monuste orseis and Pseudoplusia includens. Hitherto, the main method used to manage these pests has been the application of insecticides, which often can cause the contamination of the environment. Due to the negative impact of these pests on the cultivation of collards and the side effects of insecticide on the environment, the use of conservative biological control stands out as an appealing sustainable alternative. The conservative biological control is achieved mainly through the diversification of flowering plants within an agroecosystem. Flowering plants can provide natural enemies with alternative food such as nectar and pollen, and thus indirectly enhance biological control. The objective of this study was to evaluate how the flowering species sweet alyssum Lobularia maritima (L.) can contribute to the attraction of natural enemies and the management of pests attacking collards. Two field experiments were conducted in different growing seasons. Each experiment consisted of 2 treatments and 3 replicates, which were set up in a completely randomized design. The treatments were (i) collards alone, and (ii) collards + sweet alyssum. The experiments were conducted in following periods: From October 1,2014 to February 2015, and from October 2, 2015 to January 2016. In both experiments we evaluated weekly the population density of natural enemies and pests. The results show that the sweet alyssum flowers contributed positively to the abundance and diversity of natural enemies. The greater abundance of natural enemies observed in the treatments with sweet alyssum was of paramount importance for the suppression of insect pests attacking collards, such as whitefly and aphids. In summary, the results indicate the potential for intercropping brassica with sweet alyssum, as an important strategy for enhancing the biological control of insect pests. Finally, this strategy can be of greater importance for growers who are seeking for sustainable methods of pest management; especially organic growers who have limited choices of insecticides available.