Submitted to: Phytopathology
Publication Type: Abstract Only
Publication Acceptance Date: 5/7/2009
Publication Date: 7/26/2009
Citation: Turechek, W., Adkins, S.T., Kousik, C.S., Webster, C.G., Stansly, P.A. 2009. Epidemiological Analysis of Multi-Virus Infections of Watermelon in Experimental Fields in Southwest Florida. Phytopathology.
Technical Abstract: The whitefly-transmitted viruses Squash vein yellowing virus (SqVYV) and Cucurbit leaf crumple virus (CuLCrV) have had serious impact on watermelon production in west-central and southwest Florida in recent years. We monitored the progress of SqVYV and CuLCrV and whitefly density in 2.5 acre experimental fields of ‘Fiesta’ located in Immokalee, FL over the course of three growing seasons. Symptoms of CuLCrV were always found before SqVYV and were present as soon as 5 weeks after planting. Symptoms of SqVYV consistently appeared 7 weeks after planting and in 2 out of the 3 seasons the planting fully collapsed by week 12 from disease. The largest number of whiteflies was typically found in the weeks preceding rapid collapse of plants. Preliminary analyses indicated that the degree of association between the two diseases was not greater than what would be expected from random, and that SqVYV was distributed randomly at low incidences, but became progressively more aggregated as disease incidence increased. These results are an indication that the viruses are being introduced independently by whiteflies, although the whiteflies may be emigrating from the same source, with secondary spread being dominated by local or within-field populations of whiteflies. This is conceivable based on results in which it was discovered that the distribution of the two viruses in individual watermelon plants was somewhat spatially separated. Additional field surveys are in progress to verify and extend these findings.