Preliminary investigation on the natural enemies of Jamaican nightshade in Honduras

Jamaican nightshade (Solanum jamaicense) is an exotic plant in plant in Florida which was first recorded in 1930 near St. Cloud.  There is no information on how this plant first arrived into Florida. Since the first report, it has spread slowly and is now found in localized infestations in Osceola, Orange, Highlands and Saint Lucie counties.  There is no published research on the ecology of this plant, but observations suggest that it prefers growing in shaded areas and may spread through the consumption of fruit by deer and other wild mammals, and perhaps by cattle. 

Classical biological control of weeds involves the importation of highly host specific natural enemies from the native home of the plant into the invaded area.  Several steps are typically involved; 1) identification of the native host range of the plant, 2) surveys to identify herbivorous insects in the native range, 3) host range testing in the native range, 4) importation of promising insects into quarantine, 5) additional host range testing, 6) submission of host range data to state and federal regulatory agencies, and 7) release and evaluation (if permission to release is granted).  For Jamaican nightshade, host range testing is particularly critical as there are several species in the same genus, or related genera, which are economically important crops (e.g. eggplant, tomato, pepper, potato) or native to Florida.  However, this does not preclude the identification of host specific natural enemies, as demonstrated by the success using the leaf-feeding beetle, Gratiana boliviana, against tropical soda apple. 

The native range of Jamaican nightshade includes Central America, tropical (northern) South America and the Caribbean (Fig.1).  There are several records of the plant in Honduras where the Indian River Research and Education Center has an excellent working relationship with the Pan American School of Agriculture (Zamorano).

Objective

To identify herbivorous insects of Jamaican nightshade in Honduras as a first step towards achieving biological control in Florida.  

Activities

1. Overholt or Diaz will travel to Honduras in May, 2008 to initiate surveys with faculty and students from Zamorano.  Populations of the plant will be identified and a sampling protocol will be established.
2. Sampling will be conducted once a month at three or four locations for one year to inventory insects feeding on leaves, fruits, stems and roots.  All insect specimens will be preserved for taxonomic identification.  Other Solanum spp. growing in close proximity to Jamaican nightshade will be sampled as well to obtain an initial estimation of host range.
3. Insect specimens will be locally identified when possible.  Insects that cannot be identified in Honduras will be brought to Florida and examined by taxonomists at the University of Florida or the Florida Department of Agriculture and Consumer Services.

 Expected outputs

1. A report detailing the insect herbivores found feeding on Jamaican nightshade in Honduras.  The report will include type of damage caused, the seasonal occurrence of the insects and preliminary information on their host specificity.
2. Based on the results, we will determine whether any of the insects found have the required level of host specificity for biological control.  If so, application will be made to federal and state regulatory agencies to import one or more of these insects into the quarantine laboratory at the Indian River Research and Education Center for further studies.

Figure 1. Native range of Jamaican nightshade

Pictures

Rodrigo Diaz
Biological Control Research & Containment Laboratory

2199 South Rock Road

Fort Pierce, FL 34945-3138

Phone: 772-467-6029 Ext.228

Fax:     772-468-3973

Email: rrdg@ufl.edu