Monday, December 11, 2006
D0062

Thripinema fuscum (Tylenchida: Allantonematidae) parasitism reduces both the feeding of Frankliniella fusca (Thysanoptera: Thripidae) on peanut and the transmission of tomato spotted wilt virus

Kelly R. Sims, simsk@ufl.edu, University of Florida, Department of Entomology and Nematology, P.O. Box 110620, Gainesville, FL, Joe Funderburk, jefunderburk@ufl.edu, University of Florida, North Florida REC, 155 Research Rd, Quincy, FL, Stuart Reitz, sreitz@saa.ars.usda.gov, USDA-ARS, 6383 Mahan Dr, Tallahassee, FL, and Drion G. Boucias, pathos@ufl.edu, University of Florida, Entomology and Nematology, 970 Natural Area Drive, Gainesville, FL.

Frankliniella fusca (Hinds) (Thysanoptera: Thripidae) is the prominent thrips species found inhabiting and reproducing in peanut (Arachis hypogaea L.) and is one of at least nine thrips species to transmit Tomato spotted wilt virus (TSWV). The entomogenous nematode Thripinema fuscum (Tylenchida: Allantonematidae), a natural enemy of F. fusca, parasitizes larval and adult populations under field conditions. All known Thripinema species render the host female thrips sterile, thereby potentially suppressing pest populations to near extinction. As a result, secondary spread of TSWV in peanut is reduced. Reduction of the virus in field conditions may also be due to lower transmission rates caused by parasite-induced alterations in host feeding behavior. Therefore, the feeding rates of healthy and parasitized F. fusca cohorts on leaf discs were recorded daily and digital images subjected to image analysis. Viral transmission rates were compared daily using a local lesion assay and ELISA. The effects of wingform and sex on virus acquisition and transmission were evaluated. Thripinema fuscum greatly reduced the feeding frequency of male and female F. fusca, and hence, their persistence in transmitting TSWV. Sex appears to have a significant effect on virus acquisition and transmission, with more females acquiring the virus then males but males are more efficient at transmitting TSWV. Wingform does not appear to influence virus uptake. These results provide further evidence that T. fuscum aids in regulating viruliferous F. fusca pest populations and suggests its potential as a biological control agent for inoculative release in peanut.


Species 1: Thysanoptera Thripidae Frankliniella fusca (tobacco thrips)
Species 2: Tylenchida Allantonematidae Thripinema fuscum