Role of Warm-Season Weeds in Spotted Wilt Epidemiology in the Southeastern Coastal Plain
The role of endemic weeds in the epidemiology of spotted wilt must be determined in order to develop an integrated system to manage the disease. Field studies were conducted from 1990 through 1992 to determine concurrently the incidence of spotted wilt and population dynamics of thrips (Thysanoptera: Thripidae) on seven warm season weeds and three crop species planted in microplots. Weeds examined were Senna obtusifolia (L.) H. Irwin & Barneby (syn. Cassia obtusifolia L.] (sicklepod), C. occidentalis L. [syn. S. occidentalis (L.) Link.] (coffee senna), Jacquemontia tamnifolia (L.) Griseb. (smallflower morningglory), Ipomoea lacunosa L. (pitted morningglory), Sida spinosa L. (prickly sida), Desmodium tortuosum (Sw.) DC. (Florida beggarweed), and Xanthium strumarium L. (common cocklebur). Crops evaluated were Arachis hypogaea L. (peanut), Nicotiana tabacum L. (tobacco), and Capsicum annuum L. (bell pepper). All of the weed species were endemic to the southeastern Coastal Plain and all crops were commercially produced in the vicinity of the test site. Most of the weeds were closely related to species identified as hosts of tomato spotted wilt tospovirus (TSWV). TSWV was rarely detected in any of the weed species, while incidence in all crops increased at a linear rate throughout the growing season. Order of spotted wilt incidence in crops was peanut > tobacco > bell pepper. Thrips species diversity differed among weeds and crops. Thrips vectors were highly attracted to susceptible crops, especially peanut. While the weed species we studied were susceptible to spotted wilt, they were not preferred hosts for the thrips vectors. Any occurrence of spotted wilt in weeds is probably due to random feeding by the vector. The warm-season weeds studied did not contribute significantly to the epidemiology of spotted wilt.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
Copyright © . .