(1st Place) The effect of temperature on parasitization success: Exploring the potential for biological control of Spodoptera frugiperda in Sub-Saharan Africa using commercially available Trichogramma wasps

Fall armyworm, Spodoptera frugiperda, is a maize pest native to the Americas and invasive to Sub-saharan Africa, where it causes yield losses that threaten the food security and livelihood of smallholder farmers. Many farmers in the region manage fall armyworm damage primarily by handpicking larvae and applying pesticides, but these methods lack efficacy or economic and environmental sustainability. Biocontrol of fall armyworm by native egg parasitoids, especially those from the genus Trichogramma, is an alternative solution currently under study in Africa that has exhibited promising results. However, the parasitoids are not yet commercially produced, so they are not easily accessible to farmers. Beyond Africa, there are commercially available Trichogramma species including Trichogramma brassicae, Trichogramma minutum, and Trichogramma platneri whose capacity to parasitize fall armyworm is unknown. To explore the potential of these species as biocontrol agents, I examined their parasitism rates of fall armyworm eggs and number of offspring emerged at an expected optimal temperature of 27°C as well as 24°C, 30°C, and 33°C, temperatures that occur during the year-round maize production season in Nigeria. Trichogramma brassicae exhibited lower parasitism and offspring emergence at all temperatures. Trichogramma platneri and T. minutum performed well with similar parasitism and offspring emergence at 24°C, 27°C, and 30°C, but performed poorly at 33°C. My results indicate T. platneri and T. minutum may have potential for managing fall armyworm in Sub-saharan Africa, but high temperatures (33°C) reduce their efficacy. Biocontrol utilizing these species may help minimize the threat fall armyworm poses to affected maize growers.