Harnessing natural enemies for the biological management of seed-infesting pests

Stored-product insect pests constitute a major challenge to global food security due to their ability to infest stored seeds, leading to substantial economic losses and reduced seed viability. Biological control using parasitoids presents a more sustainable and environmentally friendly approach for pest management. Several beneficial natural enemies, including Xylocoris flavipes, Uscana sp., Anisopteromalus calandrae, Habrobracon hebetor, Theocolax elegans, Holepyris sp., and Pyemotes sp., were recorded from the collected samples of different stored seeds like cerelas, legumes and dried nuts in and around Bengaluru, Karnataka, India. The parasitism efficiency of Uscana sp. was positively correlated with the number of adults released, achieving a maximum parasitism rate of 42% on Callosobruchus maculatus eggs. This was accompanied by a reduction in seed infestation from 100% (untreated control) to 78.67% at a release rate of 40 adults, along with the highest recorded seedling vigour index (1643.3) and germination percentage (82.33%). Besides, the emergence of A. calandrae significantly increased with the numbers of mating pairs, with mean adult emergence recorded as 4.6 (1 pair), 11.9 (2 pairs), and 23.8 (4 pairs), respectively. Similarly, H. hebetor emergence varied significantly with the larval instar of the host, showing mean emergence of 2.2, 11.2, 20.2, and 25.0 from the 1st to 4th instars, respectively, indicating that later developmental stages of the host provide superior resources for parasitoid development. These experimental findings highlight the potential of egg and larval parasitoids as effective biological control agents for suppressing stored-product pest populations. Furthermore, host developmental stage and parasitoid reproductive parameters were identified as crucial factors influencing parasitism success, providing valuable insights for the optimization of post-harvest integrated pest management strategies. Documentation of natural enemies associated with major seed-infesting pests under storage conditions. Parasitism efficiency varied across pest developmental stages, with the highest suppression observed at later larval or pupal stages. A positive correlation between parasitism rates and seed quality parameters, offering scope for integration natural enemies into seed storage IPM strategies.