Abstract

EDUARDO, Wellington Ivo et al. Action thresholds for the soybean stink bug complex: phytotechnical and physiological parameters and egg parasitism. Rev. Colomb. Entomol. [online]. 2018, vol.44, n.2, pp.165-171. ISSN 0120-0488.  https://doi.org/10.25100/socolen.v44i2.7312.

Stink bugs are major soybean pests, causing damage that affects grain production and marketing. Determining action thresholds for pest control can improve the proper use of insecticides on these pests. This study aimed to evaluate five action thresholds for the management of stink bugs on soybeans, as well as their influence on phytotechnical and physiological parameters as well as on parasitism of stink bug eggs. This study was conducted in the field utilizing a completely randomized block design, using the soybean cultivar ‘Anta 82 RR’. Insecticide application treatments consisted of five action thresholds used against phytophagous stink bugs: half stink bug.m-1, one stink bug.m-1, two stink bugs.m-1, four stink bugs.m-1 and control (no insecticide sprayed), and four replications. Insect sampling was carried out using the beat cloth method, and parasitism evaluations were also taken weekly by conducting stink bug egg samplings. Soybean physiological and phytotechnical parameters, including crop yield (kg.ha-1), 100-seed weight, pod damage index PDI (%), leaf retention, plant vigor, seed viability and damage, number of seeds per pod, seeds per plant, and pods per plant were also assessed. It was observed that the most severe action thresholds used on stink bugs most positively influenced crop phytotechnical and physiological parameters. Moreover, it was noted that one stink bug.m-1 is the optimal action threshold for stink bug management on soybeans, even though egg parasitism at this level tended to be lower.

Keywords : Glycine max; parasitoids; pentatomids; multivariate analysis; Euschistus heros; Piezodorus guildinii.

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