D3024: Investigation of the use of synthetic elicitors on potato crops for management of the Colorado potato beetle and green peach aphids

The Colorado potato beetle, Leptinotarsa decemlineata Say (Coleoptera: Chrysomelidae), and the green peach aphid, Myzus persicae Sulzer (Hemiptera: Aphidiidae), are two of the most challenging insect pests in potato cultivation. Both species are known for rapidly developing resistance to insecticides, thus, it is necessary to expand the options growers have for control. Previous studies have shown chemical elicitors such as Jasmonic acid (JA) and Salicylic acid (SA) to stimulate host plant defenses with effects on insect fitness, fecundity, and behavior in other crops. We examined the use of elicitors in potato. Two experiments were conducted: (1) to evaluate the effects of different doses of a SA type elicitor, Actigard and a JA type elicitor, methyl Jasmonate against L. decemlineata fecundity. (2) To evaluate the effects of different types of SA type elicitors, Actigard and Regalia, and JA type elicitor, Blush 2x, against L. decemlineata fitness. Both studies were conducted under greenhouse conditions. Two phenological stages of the host were given foliar sprays before insect feeding. Signal competition from SA inducing insects was tested with the presence or absence of M. persicae during L. decemlineata feeding. Our findings on fecundity revealed no significant difference at any dose of either elicitor type. Our findings on fitness found that when compared to controls elicitor treatments either reduced or increased larval fitness in a significant manner that was at least partially dependent upon the host phenology and the presence of M. persicae feeding. These findings can be used to inform further field research.