Effect of plant diversification on abundance of South American tomato pinworm and predators in two cropping systems

Abstract

Several studies have demonstrated that the diversification of the agroecosystem may reduce insect pest infestation using the strategy of companion planting. We studied the effect of the presence of coriander and Gallant soldier as companion plants in the tomato crop under organic and conventional management on abundance of the tomato pests and predators. The experiment was carried out under field conditions, at Distrito Federal, Brazil, from July to October, 2004. The experimental design was of randomized blocks with three replicates in a 3 x 2 factorial arrangement [Three crop diversification levels: tomato in monoculture, tomato intercropped with coriander, and tomato intercropped with coriander and Gallant soldier; and two cropping systems: organic and conventional]. Each plot had 80 plants of the tomato and the pest-insects and predaceous arthropods were collected every week in five tomato plants/plot. Tuta absoluta (Meyr.) was the commonest pest species in both cropping systems. The tomato intercropped with coriander and Gallant soldier in organic cropping system had lower abundance and higher diversity of pests, and higher abundance and diversity of predaceous arthropods, mainly at 80 days after the tomato transplanting, coinciding with the population peak of T. absoluta (eggs and adults). The more abundant predators were spiders, lady beetles and ants. The spiders were abundant and uniformly distributed in both systems. The lady beetles appeared lately in the organic system, at the flowering season of the coriander. The ants were more abundant in the conventional systems.

Sprinkler and drip irrigation in the organic tomato for single crops and when intercropped with coriander

“…Thus, coriander may be a good choice for diversifying the cultivation system of the tomato, since besides presenting a low level of competition, as also observed by Medeiros, Sujii and Morais (2009), it provides the producer with extra income.…”

“…According to Lopes and Café Filho (2006) and Medeiros, Sujii and Morais (2011), a reduction in the infestation of tomato pinworm under sprinkler irrigation happens mainly due to the removal of eggs and small larvae by the impact of water droplets, especially on the upper third of staked tomato plants. Medeiros, Sujii and Morais (2009) and Togni et al (2009) however, report that the coriander allows natural enemies of the tomato pinworm to become established.…”

“…Recent work (MAROUELLI et al, 2011a;MORAIS, 2009) has shown that the cultivation of coriander (Coriandrum sativum L.) intercropped with the tomato may reduce the population densities of tomato leafminer (Tuta absoluta (Meyr.) and whitefly (Bemisia tabaci Genn., biotype B).…”

Influência de diferentes cultivos e fatores climáticos na ocorrência de crisopídeos em sistema agroecológico

“…Menor riqueza de espé-cies foi observada por Medeiros et al (2009), que coletaram apenas C. externa em cultivo orgânico de tomate consorciado com coentro, conduzido em área de produção diversificada de hortaliças sob manejo agroecológico, em Brasília (DF). O menor número de espécies de crisopídeos em agroecossistemas em comparação aos ecossistemas naturais já fora relatada por Cardoso et al (2003).…”

Oviposition deterrent activity of basil plants and their essentials oils against Tuta absoluta (Lepidoptera: Gelechiidae)

“…To our knowledge, the only example in the published literature is the association of coriander herbs (Coriadrum sativum L.) (Apiaceae) and gallant soldier (Galinsoga parviflora Cav.) (Asteraceae) to reduce T. absoluta abundance and increase auxiliary predators, like ladybugs and spiders, when intercropping with tomato plants (Medeiros et al 2009). Our study was the first to highlight the repellent effect of Ocimum species on T. absoluta females.…”