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ABSTRACT
Whitfield, A. E., Campbell, L. R., Sherwood, J. L., and Ullman, D. E. 2003. Tissue blot immunoassay for detection of Tomato spotted wilt virus in Ranunculus asiaticus and other ornamentals. Plant Dis. 87:618-622.
A tissue blot immunoassay (TBIA) was developed to detect Tomato spotted wilt virus (TSWV) in Ranunculus asiaticus tubers and other ornamentals. TBIA was comparable to double-antibody sandwich enzyme-linked immunosorbent assay for accuracy and reliability. A nondestructive sampling method was used with R. asiaticus tubers to determine: (i) the relationship between tuber infection and size; (ii) the distribution of TSWV in tubers; and (iii) the relationship between tuber infection and tuber germination. Small tubers had a higher percentage (44%) of infection than large tubers (19%). When destructive sampling was acceptable, the central stem tissue was the most reliable to test. TSWV infection was associated with a significant reduction of tuber germination. Among the tubers that tested positive for TSWV infection, 48% of those that germinated produced foliage in which TSWV was detected. The remaining 52% of the infected tubers planted that germinated developed into plants that were asymptomatic and in which TSWV was not detectable after germination. Only 4% of tubers that tested negative produced infected plants after germination. Our results indicate that TBIA can be used in TSWV management programs to identify infected plants and to index tuber crops.
Additional keywords: Frankliniella occidentalis, tospovirus
Tomato spotted wilt virus (TSWV), the type member of the genus Tospovirus (family Bunyaviridae) (6), is an increasing problem for production of agricultural and ornamental crops worldwide (5,7). The virus has an extremely wide host range of over 650 species, including dicots and monocots (7). TSWV causes diverse symptoms that include ring spots, stem necrosis, mosaic, petiole necrosis, and stunting, which may vary with the host. For example, a survey of 511 commercial greenhouses in Pennsylvania revealed that only 38% of the plants infected with tospoviruses exhibited the characteristic ringspot symptom associated with TSWV infection (9). Virus infection also decreases flower quality and the number of flowers per stem (15). In addition, symptom expression in some crops can be delayed for up to 2 months postinfection (e.g., chrysanthemum and dahlia), resulting in infected plants serving as symptomless reservoirs of TSWV (1,15,25). Similarities between some tospovirus...