Integration of egg parasitoids and entomopathogens for the management of fall armyworm Spodoptera frugiperda on maize in Ghana

Abstract

The effectiveness of combining biological agents, comprising Telenomus remus, Beauveria bassiana, and Metarhabditis rainai, against the fall armyworm (Spodoptera frugiperda J. E. Smith) in maize fields across two ecological zones in Ghana was evaluated. The four treatments tested were sole T. remus, T. remus + M. rainai, T. remus + B. bassiana, and T. remus + M. rainai + B. bassiana, with the entomopathogens applied 24 h after T. remus release. Parameters collected included parasitized egg masses and larval mortality of S. frugiperda, maize leaf and cob damage, re-infestation after treatment and yield. Egg parasitism rates (43.24–61.53%) were similar across treatments, indicating the compatibility of the parasitoid and entomopathogens. However, larval mortality was significantly higher (75.00–87.65%) in combined treatments compared to sole T. remus (4.03–7.89%) with increased yield. Leaf damage varied, with the highest levels recorded in plots treated with T. remus, while cob damage remained consistently low across treatments. Ecological zone type influenced egg parasitism, re-infestation, and yield. Incorporating T. remus with these entomopathogens into Integrated Pest Management (IPM) strategies as one of the components significantly reduced fall armyworm damage in Ghana.