Releases, distribution and abundance of Gratiana boliviana (Coleoptera: Chrysomelidae), a biological control agent of tropical soda apple (Solanum viarum, Solanaceae) in Florida

Abstract

From 2003 to 2008, 176,643 Gratiana boliviana Spaeth (Coleoptera: Chrysomelidae) were released in Florida as part of a biological control program targeting tropical soda apple (TSA) Solanum viarum Dunal (Solanaceae). The spatial distribution of releases was clustered with more beetles released in south/central Florida than further north. A survey conducted in the fall of 2008 found G. bolviana present at >70% of randomly selected locations between 26° and 29° latitude, but no beetles were found at sites further north. The presence of beetles and beetle damage were associated with smaller TSA plants and fewer fruits per plant. The absence of beetles in northern Florida may be due to the fewer number released in that area, but also could be influenced by land cover and climate.