Comparative Studies of the Effects of Nutrient-Based Phagostimulants on Six Lepidopterous Insect Pests

Abstract

The effects of five commercial, nutrient-based phagostimulants-Pheast (AgriSense), Coax (CCT), Gusto (Atochem North America), Entice (Custom Chemicides), and Mo-Bait (Loveland Industries)-on the feeding behavior of six lepidopteran insect species were compared. The species were gypsy moth, Lymantria dispar (L.) (Lymantriidae); com earworm, Helicoverpa (Heliothis) zea (Boddie); fall armyworm, Spodoptera frugiperda (J. E. Smith); beet armyworm, S. exigua (Hubner) (Noctuidae); European com borer, Ostrinia nubilalis (Hübner) (Pyralidae); and diamondback moth, Plutella xylostella (L.) (Plutellidae). Consumption of cellulose-agar media containing phagostimulants and of leaf disks treated with phagostimulants was measured. Comparisons of responses of larvae in terms of attraction and arrestancy were made with untreated filter paper or filter paper treated with phagostimulant. Large differences in consumption between phagostimulants were found when we used cellulose-agar media. However, differences in consumption were smaller when plant material was used as a substrate, especially in choice (treated versus control) tests. The four phagostimulants that contained high percentages of protein generally elicited stronger responses than the phagostimulant containing primarily sugars (Mo-Bait). Overall, Pheast tended to elicit the greatest response; Mo-Bait, elicited the least. Some attractancy and arrestancy were noted, except with L. dispar, but no differences between phagostimulants were found. The methods used here for the comparative evaluation of phagostimulants should be useful in developing practical applications of feeding stimulants to increase the efficacy of microbial and other insect control agents under practical field conditions.