Augmentative release of the predatory earwig combined with selective insecticides improves pest management in pak choi crops

The ring-legged earwig, Euborellia annulipes (Lucas) (Dermaptera: Anisolabididae), is a generalist predator found in numerous agroecosystems. The species can be mass-reared at low cost, making it a feasible alternative for brassica pest management. Integrating biological control with selective insecticides is essential for sustainable pest management in brassica crops, particularly due to the demand for fresh products. This study investigated E . annulipes as a biocontrol agent against a complex of pests in pak choi cabbage over four production cycles, which included both grower field and small plot experiments. It investigated releases of one, two and four earwigs per two plants during the pak choi crop development. Two crop cycles were conducted under commercial field conditions and another two growing cycles using experimental microplots to assess its integration with selective insecticides. The release of four earwigs per two plants resulted in effective pest management in both cycles. Other densities also yielded positive results compared to control plots that were not treated with insecticides or earwigs. In addition, the study found that releasing earwigs reduced insecticide use in one cycle while also increasing successful pest population suppression, as it combined chemical and biological control (using the predatory earwig) throughout two productive cycles in experimental plots. Consequently, incorporating E. annulipes into Brassica pest management offers an opportunity to reduce reliance on insecticides without compromising crop quality. Although the efficacy of using a predator alone was often marginal, its integration into an IPM framework reduced insecticide applications during specific cycles. • Four experiments in grower fields and experimental plots evaluated earwigs and selective insecticides for managing pak choi cabbage pests. • The survey found low insect infestations across all experiments, with predator releases playing a significant role. • The release rates of 1, 2, and 4 earwigs per plot resulted in reduced insect infestation, with 4 earwigs per plot being the most effective. • Earwig releases and selective insecticide applications reduced insecticide use.