Biological Control with Gratiana boliviana

Host Specificity

Many different insect species typically feed on a plant in the plant’s native range, some of which are generalists (feeding on many different plants), while others are specialists and feed only on one or a few plant species.  Insects used for biological control are specialists which feed and maintain viable populations only on the target weed.  Prior to their release, biological control agents undergo extensive host range testing to make sure that they will only feed on the target weed.  In the case of Gratiana boliviana, scientists from the University of Florida and the USDA evaluated beetle survival, development and egg laying preference on 123 different plant species, including several close relatives of tropical soda apple, as well as many important crops. Beetles laid eggs and survived only on TSA. Thus, they were able to demonstrate that this beetle was a specialist on TSA.

After several laboratory and field experiments, scientists submitted their data to federal and state agencies for review. A permit was approved in early 2003, and the beetle was Polk Co., Florida in May of the same year. Field monitoring in Florida has demonstrated that the only plant attacked by Gratiana boliviana is tropical soda apple.

We encourage people to familiarize themselves with the science of weed biological control. For more information about how scientists evaluated the specificity of Gratiana boliviana, please read the following paper:

Medal J, Sudbrink D, Gandolfo D, Ohashi D, Cuda JP. 2002. Gratiana boliviana, a   potential biocontrol agent of Solanum viarum: Quarantine host-specificity testing     in Florida and field surveys in South America. BioControl 47: 445-461.