Effectiveness of trap crops for the control of stinkbugs (Heteroptera pentatomidae) in edible Cucurbitaceae species, in Limpopo Province, South Africa

Abstract

Four trap crops were tested for their ability to intercept stinkbugs (Heteroptera pentatomidae) in a cucurbit field crop at Waterpoort, Limpopo Province. The experimental trap crops were: Sunnhemp (Crotolaria juncea), okra (Abelmoschus esculentum), mustard mixture (Brassica hirta and Brassica juncea) and cowpea (Vigna unguiculata). The surveys were based on visual counts of stinkbugs from all the trap crops. Stinkbugs were collected from trap crops in a field crop trial of cantaloupe (Cucumis melo). The correlation between Brassica hirta and Brassica juncea with other trap crops had a great variance. The repeated B. hirta and B. juncea inner row experiment in 2012 interestingly lured the green stinkbug (Nezara viridula) into the cantaloupe field. Amongst the entire trap crops, stinkbugs recovered from Brassica hirta and Bassica juncea, exceeded the average of the other three trap crops. The number of adult N. viridula captured had significantly increased in March 2012 and started to drop on the B. hirta and B. juncea mixture in the first week of April. During this increase, the crops were at the seeding stage. The perimeter trap-cropping system practiced for all four trap crops varied in the attraction of stinkbugs along the perimeter of the field and inner row. B. hirta and B. juncea attracted a high number of N. viridula along the perimeter but fewer in the inner row. The B. hirta and B. juncea recorded the highest number of N. viridula in the inner rows and outer rows, compared to the other four trap crops, followed by V. ungiuculata. This study has demonstrated a significant potential of using trap crops as biological alternative for managing stinkbug pests in cucurbit crops.