2012 Annual Report
Two master’s students at the FAMU Center for Biological Control are working with the research team. The tropical soda apple (TSA) work will be the basis for a M.S. thesis for one student and the leafminer work the basis for the other student.
Tropical soda apple is a key noxious weed pest of pastures in the southern USA and can harbor insect transmitted viruses of vegetable crops. One of the key viruses it can harbor is the thrips-vectored tomato spotted wilt virus (TSWV). Scientists with the Center for Biological Control, Florida A&M University have initiated studies in cooperation with scientists with USDA-ARS-CMAVE to determine if western flower thrips (WFT) can transmit TSWV from infected TSA, a known reservoir of the virus, and the level at which WFT is found inhabiting stands of naturally growing TSA. Additional aspects of the study are to establish the effect that crop pollens may have on ovipositional rate of thrips on TSA.
Although the leafminers Liriomyza sativae and L. trifolii (Diptera: Agromyzidae) are already important pests in U.S. horticultural and ornamental crops, additional pest species of Liriomyza pose invasive threats to the U.S. In particular, Liriomyza huidobrensis, the pea leafminer, which is closely related to these species, is considered by APHIS to be a pest of quarantine significance that poses a high risk for introduction into the U.S. Florida is particularly concerned by the threats posed from invasive species.
Given this possibility of introduction, it is critical to proactively develop management tactics for the pea leafminer should it become established in the US. It is well established that in many cases hymenopteran parasitoids of leafminers can provide acceptable control in the absence of insecticide spraying. Most of these parasitoid species that attack L. sativae and L. trifolii are also able attack the pea leafminer. Thus, improved biological control has the potential to reduce the use of harmful agrochemicals in vegetable fields and mitigate pest pressure from invasive species. Surveys have been initiated to determine the prevalence of L. sativae and L. trifollii in vegetable production in Tallahassee, FL. Multiple vegetable species in Solanaceae (pepper, eggplant, tomato, tomatillo), Cucurbitaceae (squach, pumpkin), Brassicaceae (cabbage, turnip, mustard), Malvaceae (cotton, okra), Amaranthaceae (spinach), Leguminacea (bean, pea) are some of the families being surveyed for leafminers and associated parasitoids.
The goal in this project is to provide information on plant-leafminer-parasitoid associations in order to explore food web dynamics involving leafminers established in Florida, and to relate these to potential hosts of the pea leafminer. These data will enable predictions of which parasitoids would be most suitable to target for conservation/augmentation for various crops that may be attacked by the invasive pea leafminer.