DISEASE PROGRESS OF SPOTTED WILT IN PEANUT CULTIVARS FLORUNNER AND SOUTHERN RUNNER

Early season abundance of tobacco thrips (Frankliniella fusca) and incidence and disease progress of spotted wilt, caused by tomato spotted wilt virus (TSWV), were compared in Florunner and Southern Runner peanut (Arachis hypogaea) cultivars in field studies in 1989-1991. In replicated plot experiments and large field quadrat studies, populations of tobacco thrips adults and thrips larvae were similar for the two cultivars. In 1989 and 1991, cultivar, time, and cultivar X time interaction effects on incidence of spotted wilt were significant in all replicated plot studies except one. In all experiments, incidence of spotted wilt progressed linearly in both cultivars. Linear regression of disease incidence over time indicated disease incidence increased more rapidly in Florunner than in Southern Runner. Final incidence of spotted wilt was lower in Southern Runner than in Florunner in all but one experiment. Final apparent incidence of spotted wilt in Florunner was approximately twice as high as that in Southern Runner in tests in which average final incidence in Florunner ranged from 0.034 to 0.268.