Dinâmica populacional de Bemisia tabaci biótipo B em tomate monocultivo e consorciado com coentro sob cultivo orgânico e convencional

Abstract

Population dynamic of Benisua tabaci B biotype in monoculture tomato crop and consortium with coriander in organic and conventional crop system Due to its high genotypic plasticity, the control of the silverleaf whitefly Bemisia tabaci B biotype (Hemiptera: Aleyrodidae), is difficult. This insect may cause severe damage to the tomato crop as a vector of several viruses. The management of the production system and the consortium with other crops may have a direct effect on this herbivore population, without the need of chemical insecticide spraying. The effect of organic and conventional production systems and the tomato-coriander consortium were evaluated in this study, in field, during May-September 2006. Adults of whitefly and its natural enemies were monitored using yellow adhesive traps installed at the edge and inside the experimental plots, and nymphs were sampled by direct observation on tomato plants. Although adult populations in the neighborhood of the different treatments were equivalent, the abundance of whitefly adults was significantly lower in the plots with the consortium tomato-coriander in both systems, conventional and organic. Significant reduction in the amount of nymphs per plant was only observed in the consortium tomato-coriander when all treatments were compared. There were more natural enemies in organic system and a negative correlation was observed between natural enemies abundance collected in the traps and whitefly nymphs' density. The association tomato-coriander and the organic management of the agroecossystem favored natural biological control of B. tabaci.

Integrated cultural practices for whitefly management in organic tomato

“…The significant reduction in B. tabaci populations observed in the present study by intercropping tomato plants with coriander plants confirmed the patterns observed by Hilje and Stansly () and Togni et al. (), who tested the same intercrop in conventional farming systems in Costa Rica and Brazil, respectively. Hilje and Stansly () argue that coriander plants may hide the shorter tomato plants at the beginning of the tomato crop.…”

Correlation of climatic factors between the development of tomato cultivars (Solanum lycopersicum L., Solanaceae) with adults of two key pests

“…Santa Clara was the most susceptible and Cereja was least susceptible, or most resistant, to attacks by two key pests. Baldin et al (2007) and Togni et al (2009) obtained similar results, in controlled studies using extracts of plants in a greenhouse. Oliveira et al (2008), in a study of T. absoluta, obtained significant results, corroborating this study in terms of climatic variables.…”

Cascading effects of combining synthetic herbivore‐induced plant volatiles with companion plants to manipulate natural enemies in an agro‐ecosystem

“…Coriander, Coriandrum sativum cv. ‘Verdão’, was used as a companion plant because previous studies have shown that coriander when intercropped with cabbage, tomato, carrot, eggplant, and rose plants attracts natural enemies – for example, lacewings (Chrysopidae), hoverflies (Syrphidae), and ladybeetles (Coccinellidae). Coriander emits volatiles throughout all vegetative stages, which are known to be attractive to natural enemies .…”

“…We tested this hypothesis in a system consisting of common bean ( Phaseolus vulgaris L.) plants, the HIPV MeSA, and coriander ( Coriandrum sativum L.) as a companion plant. Both MeSA and coriander have been shown to attract natural enemies of herbivores in agro‐ecosystems (see below). We predicted that MeSA and coriander would interact synergistically to alter the arthropod community, i.e.…”