Figure A. Leaf deformation and mosaic observed on green bean leaves.
Click on photograph for larger view (60 KB).
Received from:
Scott Adkins
Bill Turechek
USDA-ARS-USHRL
Fort Pierce, FL 34945
(772)-462-5885 or Scott.Adkins@ars.usda.gov
(772)-462-5857 or William.Turechek@ars.usda.gov
Symptoms consistent with virus infection were observed on green bean (Phaseolus vulgaris) plants in Hendry County (southwest Florida) in mid-December 2007. Symptoms on green bean plants included leaf deformation and rugosity (Figs. A, B and C), especially of younger leaves, and a mild (Fig. C) or chlorotic mosaic (Figs. D and E). Serological tests (ELISA) for potyviruses and cucumber mosaic virus were negative. Molecular assays (dot blot hybridization) with sap from homogenized green bean leaves were positive for cucurbit leaf crumple virus (CuLCrV). Nucleic acid was subsequently extracted from green bean leaves and used in an additional molecular assay (PCR) to confirm the presence of CuLCrV by sequence analysis. All eleven symptomatic green bean samples were infected with CuLCrV but none of four non-symptomatic samples were.
The green bean field from which these samples were collected was adjacent to a watermelon field with confirmed CuLCrV and squash vein yellowing virus (SqVYV) infections. To our knowledge, this is the first report of CuLCrV infecting any host other than cucurbits in Florida. This finding suggests that CuLCrV may be more widely distributed than previously known in Florida and that green beans (and potentially other legumes) may become an important reservoir host of CuLCrV in the state.
CuLCrV was first described concurrently in California, and Arizona and Mexico in the late 1990's where it was reported to infect cucurbits, beans and tobacco. It was subsequently found in Texas. In the fall of 2006 CuLCrV was identified in north-central Florida in squash and in the spring of 2007 it was identified in southwest Florida in watermelon. During the remainder of 2007 CuLCrV was also found in west-central Florida in squash and watermelon.
CuLCrV is transmitted by whiteflies (Bemisia tabaci) and is not mechanically transmissible. It is unlikely to be seed transmissible. In Florida, CuLCrV has been observed to induce chlorotic mottling and crumpling of squash leaves, and color break in the fruit of yellow squash. It also induces chlorotic mottling of watermelon leaves and can stunt watermelon plants when they are infected at an early age. This can lead to a reduction in watermelon fruit size but the fruit are not discolored or distorted in shape, unlike infection by the previously described and whitefly-transmitted SqVYV, the cause of watermelon vine decline in Florida.
Additional information on CuLCrV is available at:
Whitefly-transmitted cucurbit leaf crumple virus in Florida. (2007). S.E. Webb, F. Akad, T.W. Nyoike, O.E. Liburd, and J.E. Polston. UF/IFAS. EDIS. ENY-477. http://edis.ifas.ufl.edu/pdffiles/IN/IN71600.pdf
New virus disease in melons and squash is identified and described. E.T. Natwick. University of California Delivers. http://ucanr.org/delivers/impactview.cfm?impactnum=140
Triple threat for cucurbits. (2007). A. Whidden, J. Polston, P. Gilreath, and S. Adkins. The Vegetarian Newsletter. http://www.hos.ufl.edu/vegetarian/07/December%2007/Triple%20Threat%20for%20Cucurbits.htm