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Tomato spotted wilt caused by thrips-vectored tomato spotted wilt virus (TSWV) is a very serious problem in peanut (Arachis hypogaea L.) production. TSWV and the thrips Frankliniella fusca and Frankliniella occidentalis, which vector the virus, present a difficult and complicated challenge from the perspectives of both epidemiology and disease management. Simply controlling the vector typically has not resulted in control of spotted wilt. No single measure can currently provide adequate control of spotted wilt where severe epidemics occur. However, interdisciplinary investigations have resulted in development of integrated management systems that make use of moderately resistant cultivars and chemical and cultural practices, each of which helps to suppress spotted wilt epidemics. Such systems have been successfully deployed in many areas for minimizing losses to this disease. The development of a spotted wilt risk index has aided greatly in relaying information on the importance of using an integrated approach for managing this disease.

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Epidemics of spotted wilt, caused by tomato spotted wilt tospovirus (TSWV), were monitored in field plots of the new runner-type peanut (Arachis hypogaea) cv. UF 91108, in advanced breeding line F 84 × 9B-4-2-1-1-2-b2-B, in runner-type peanut cvs. Southern Runner and Florunner, and in Virginia-type cv. NC-V11 at two locations in 1994 and 1995. Epidemics of spotted wilt were suppressed in UF 91108 compared to the standard runner-type cv. Florunner. Final disease incidence, standardized area under the disease progress curve values, and final disease intensity ratings were lower in UF 91108 than in Florunner and were similar to those in the moderately resistant cv. Southern Runner. Results indicate that new cv. UF 91108 represents a new potential tool for management of spotted wilt in peanut production areas of the southeastern United States. UF 91108 is the first peanut cultivar in which an oil composition of approximately 65% oleic acid is combined with a moderate level of field resistance to TSWV. Epidemics of spotted wilt also were suppressed in breeding line F 84 × 9B-4-2-1-1-2-b2-B. Across the four tests, the effects of NC-V11 on epidemic development, final incidence, and spotted wilt intensity ratings were not consistent relative to the other genotypes. Use of final disease intensity ratings provided separation of the genotypes similar to use of final incidence of spotted wilt. Assessment values by these two methods were highly correlated. In three of four experiments, final disease intensity ratings were more closely correlated with pod yield than was final incidence. The new intensity rating method described in this paper requires much less time and effort than determining disease incidence and may be a practical alternative to individual plant assessment for characterization of genotype responses to TSWV.