Evaluation of a spinetoram-based insecticide against lepidopteran and thrips infesting acacia and eucalyptus in Sumatra, Indonesia

Abstract

Feeding by the Spodoptera exigua (Hubner, 1818) (Lepidoptera: Noctuidae) and Scirtothrips sp. (Thysanoptera: Thripidae) cause damage to Acacia crassicarpa A. Cunn. ex Benth. (Fabaceae) plants and these pests are key factors affecting the production in nurseries. Leafroller, Strepsicrates semicanella (Walker, 1866) (Lepidoptera: Tortricidae) cause severe damage to young Eucalyptus spp. (Myrtaceae) plantations. Use of low-hazard insecticide with the conservation of populations of natural enemies integrates effective management. Nursery and field experiments were conducted in 2018-2019 to evaluate the low-hazard insecticide, spinetoram for control of lepidopteran and thrips. Insecticides were applied in combination with surfactant. A spinetoram-based solution (0.12%) was exceedingly effective for the control of S. exigua and thrips in nursery. Effectiveness of spinetoram-based solution (0.12%) was 100% to S. exigua and 95% to Scirtothrips sp. at 15 days after treatment (DAT). Severity of Scirtothrips sp. was 5.3% in the spinetoram (0.12%) treatment while it was 80% in standard check chlorpyrifos (0.4%) and 96% in untreated control at 15 DAT. Spinetoram at 12 g a.i./ha was significantly effective than standard check imidacloprid at 20 g a.i./ha against S. semicanella in Eucalyptus spp. plantation reducing severity from 58 to 2.8% at 30 DAT. Spinetoram at five, seven and 10 g a.i./ha was on par (P≤ 0.05%) at 10 DAT compared to 2 g a.i./ha and untreated control against S. semicanella. Spinetoram has broad insecticidal spectrum activity and reliable indices for integrated pest management strategies against major pests of A. crassicarpa and Eucalyptus spp.