Includes bibliographical references and index.

Egg parasitoids, especially the Trichogrammatidae family, are widely used around the world in biocontrol programs. The behavior of these entomophagous insects is influenced in various ways by chemicals produced by their host or prey. Chemicals like kairomones are substances released by one insect species that trigger advantageous behavioral and physiological responses in the recipient. Among the Trichogramma species, especially Trichogramma pretiosum has been exploited as a potential biological control agent for Fall Armyworm (FAW), Spodoptera frugiperda. FAW is the most destructive pest of many economically important crops across the globe. Considering the invasiveness and spread of FAW, it is essential to prevent its infestation in the early stages in the field. Therefore, the present study was undertaken to generate information on the potential of host insect kairomones in improving the performance of T. pretiosum in parasitizing S. frugiperda. Initially, a prototype of a four-armed olfactometer was developed for tracking the movements of T. pretiosum and successfully validated by introducing chemical cues to its arms. Subsequently, it was used for laboratory bioassays. Extracts from Corcyra cephalonica and S. frugiperda eggs and moths were assessed for their kairomonal effects using this olfactometer, which effectively enhanced the performance of T. pretiosum. The most effective extracts, C. cephalonica eggs, and S. frugiperda female, were selected and tested in various concentrations through Petri dish bioassays. C1 (10%) of C. cephalonica eggs extract showed the highest PAI, per cent parasitization, and adult emergence. In contrast, C1 (10%) of S. frugiperda female extract exhibited the highest PAI, while C2 (1%) had the highest percentage of parasitization and adult emergence. These concentrations, along with C3 (0.1%), were further investigated on potted maize plants in a polyhouse. The parasitoid's response to egg cards treated with hexane extracts decreased as the distance from the release point increased. In the polyhouse, egg cards positioned 1 meter from the release point, treated with C1 (10%) of C. cephalonica eggs extract, achieved the highest mean percentage parasitization. Conversely, egg cards treated with C2 (1%) of S. frugiperda female extract, positioned at 1 meter, recorded the highest mean percentage parasitization. The chemical composition of these extracts was analyzed via GC-MS. S. frugiperda female extract contained 12 hydrocarbons and 3 alcohol groups. These include heptane, octane, nonane, etc., with tetracontane being the most prevalent hydrocarbon. In C. cephalonica eggs extract, 9 hydrocarbons and 1 alcohol group were detected, in which dodecane had the highest area percentage among the hydrocarbons followed by decane, nonane, etc. The hexane extracts obtained from the eggs and moth stages of both C. cephalonica and S. frugiperda distinctly influence the performance of T. pretiosum and have the potential to significantly impact parasitoid activity manipulation in biological control initiatives. The identification, synthesis, and field use of these kairomonal compounds could revolutionize pest management and could boost the potential of predators and parasitoids, strengthening the superiority of biological control in pest management.