Survival assays were conducted with beet armyworm Spodoptera exigua (Hübner) and southern armyworm S. eridania (Stoll) with tropical soda apple Solanum viarum Dunal, a relative of tomato. In addition, polyphenol oxidase (PPO) enzyme assays were conducted to determine if plant defense compounds are being produced by tropical soda apple in response to herbivory. Both S. exigua and S. eridania induced plant defenses in tropical soda apple. Significantly more S. exigua and S. eridania neonate larvae survived to 2^nd instar on non-induced plants and artificial diet when compared with plants with induced defenses. Tropical soda apple plants fed on by S. exigua and S. eridania had significantly increased PPO activity.