ARS | Publication request: Tropical soda apple (Solanum viarum) mediated competition via induced resistance: Interaction between Gratiana boliviana, Spodoptera exigua and Frankliniella occidentalis

Submitted to: Florida Entomologist
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: August 23, 2011
Publication Date: September 30, 2011
Repository URL: http://www.bioone.org/doi/full/10.1653/024.094.0327
Citation: Kariuki, E.M., Hix, R.L., Reitz, S.R., Hight, S.D., Kairo, M. 2011. Tropical soda apple (Solanum viarum) mediated competition via induced resistance: Interaction between Gratiana boliviana, Spodoptera exigua and Frankliniella occidentalis. Florida Entomologist. 94(3):608-612.

Interpretive Summary: Invasive weeds cause direct damage to natural resources and agricultural lands, and they also can serve as alternate hosts for many insect pests of agricultural crops. Biological control of weeds may therefore help reduce populations of insect pests that infest crops. To address this idea, scientists with the USDA-ARS Center for Medical, Agricultural and Veterinary Entomology, Gainesville, Florida, and the Center for Biological Control at Florida A&M University, determined how feeding by a weed biological control agent, a leaf bettle, on the invasive tropical soda apple would affect two important crop pests, the beet armyworm and the western flower thrips. Feeding by the leaf beetle induced a systemic response in tropical soda apple that reduced the survivorship of the beet armyworm. Beetle feeding did not affect oviposition preference of western flower thrips, but thrips had low survivorship on tropical soda apple. These results demonstrate the additional benefits for crop protection that biological control of weeds can provide.

Technical Abstract: Survival assays were conducted with beet armyworm (BAW) Spodoptera exigua (Hübner), a tortoise beetle Gratiana bolivana Spaeth and western flower thrips (WFT) Frankliniella occidentalis (Pergande) on tropical soda apple (TSA) Solanum viarum Dunal, a relative of tomato. Both S. exigua and G. boliviana seem to induce plant defenses in tropical soda apple. Significantly more S. exigua neonate larvae survived to 2nd instar on non-induced plants and artificial diet when compared with plants with induced defenses. Our results further suggest that the induced response in TSA was systemic, since BAW neonates suffered higher mortality in induced plants despite not being in direct contact with the damaged part of the plant. Results suggested that feeding action of G. boliviana on TSA had no significant influence on WFT host choice.