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ARS Home » Southeast Area » Gainesville, Florida » Center for Medical, Agricultural and Veterinary Entomology » Insect Behavior and Biocontrol Research » Research » Publications at this Location » Publication #321833
Title: Influence of sun and shade conditions on Gratiana boliviana (Coleoptera: Chrysomelidae) abundance and feeding activity on tropical soda apple (Solanaceae) under field conditions

Author
item KARIUKI, EUTYCHUS - Florida A & M University
item HIX, RAYMOND - Florida A & M University
item Hight, Stephen
item REITZ, STUART - Oregon State University
item KAIRO, MOSES - University Of Maryland Eastern Shore (UMES)

Submitted to: Florida Entomologist
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/23/2016
Publication Date: 9/1/2016
Citation: Kariuki, E., Hix, R., Hight, S.D., Reitz, S.R., Kairo, M.T. 2016. Influence of sun and shade conditions on Gratiana boliviana (Coleoptera: Chrysomelidae) abundance and feeding activity on tropical soda apple (Solanaceae) under field conditions. Florida Entomologist. 99(3):552-554. https://doi.org/10.1653/024.099.0334.
DOI: https://doi.org/10.1653/024.099.0334

Interpretive Summary: Tropical soda apple (TSA) is native to South America but was accidently introduced into Florida and has become a problem in pastures and natural areas. Cattle avoid the spiny leaves and stems of TSA and the weed can dominate over pasture plants. To control TSA without using chemicals, explorations in Argentina identified a leaf-feeding beetle that could only survive on TSA and the insect was introduced into Florida. Scientists with USDA, Agriculture Research Service, Center for Medical, Agricultural and Veterinary Entomology, Tallahassee, Florida, in collaboration with researchers from Florida A&M University, Tallahassee, Florida, evaluated the presence and feeding activity of the beetle as a biological control agent on pasture TSA plants growing in shady or sunny conditions. The study showed that beetle abundance and associated feeding damage were greater on plants growing in full sun compared to plants growing in shaded habitats. Cattle often increase the density of TSA in shaded areas by spreading undigested seeds to the shaded areas where they rest. Additional efforts at releasing beetles into shaded areas and/or integrated control efforts to control plants in the shade may be necessary to limit the dispersal and reduce the dentsity of TSA plants in shaded pasture habitats.

Technical Abstract: Tropical soda apple (Solanum viarum Dunal) is a perennial invasive weed species which has become a serious problem in both agricultural and natural areas of the southeastern United States. A field survey was conducted at a ranch in Madison County, Florida, to assess the effect of sun and shade conditions on the abundance and feeding activity of the biological control agent Gratiana boliviana (Coleoptera: Chrysomelidae) on tropical soda apple. The results revealed that beetle abundance and their feeding damage were greater on plants growing in full sun exposure than on plants growing in shaded habitats. Targeted releases of G. boliviana in shady conditions may be required since dense TSA stands can often form under shaded areas where cattle avoid summer sun.