Investigation of Glycocidal Content of Stevia rebaudiana and Its Impact on Fall Armyworm (Spodoptera frugiperda)

Select glycocides of Stevia rebaudiana are used in commercial sweetening products, due to their zero-calorie nature. While the impact to human physiology has been explored, the uses of these compounds on crop pests has not. A study was initiated to evaluate possible uses of S. rebaudiana as a repellent or insecticide of BT-resistant Spodoptera frugiperda. Three cultivars of S. rebaudiana were chosen to document the composition of glycosides across the cultivars and within plants. Ten plants of each cultivar were grown in a greenhouse, and leaves were harvested from the bottom, middle, and top thirds of each plant. Glycosidal compounds were analyzed using the Common Stevia Glycosides Standards Kit developed for HPLC. Harvested leaves were used to assess the impact of these cultivars on feeding and survival of S. frugiperda.  One neonate of S. frugiperda was placed in a 29.57-ml cup with one of eight diet treatments: normal growth diet (control), soy foliage only, each of three S. rebaudiana cultivars only, and soy in combination with each of the three S. rebaudiana cultivars. Insect viability and mortality were monitored in the ten replications for every diet. Glycocidal composition and impacts to S. frugiperda will be presented and discussed.