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ARS Home » Pacific West Area » Salinas, California » Crop Improvement and Protection Research » Research » Publications at this Location » Publication #299166

Research Project: Biology, Epidemiology and Management of Vector-Borne Viruses of Sugarbeet and Vegetable Crops

Location: Crop Improvement and Protection Research

Title: Host-specific relationship between virus titer and whitefly transmission of Cucurbit yellow stunting disorder virus

Author
item Wintermantel, William - Bill
item GILBERTSON, ROBERT - University Of California
item McCreight, James - Jim
item NATWICK, ERIC - University Of California - Cooperative Extension Service

Submitted to: Plant Disease
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/29/2015
Publication Date: 7/9/2015
Citation: Wintermantel, W.M., Gilbertson, R.L., Mccreight, J.D., Natwick, E.T. 2015. Host-specific relationship between virus titer and whitefly transmission of Cucurbit yellow stunting disorder virus. Plant Disease. doi: 10.1094/PDIS-11-14-1119-RE.

Interpretive Summary: Cucurbit yellow stunting disorder virus (CYSDV) emerged in Imperial Valley, CA in 2006, and is now firmly established in the region, where it is transmitted efficiently by the sweet potato whitefly. In order to evaluate spread and establishment of the virus during the spring and fall melon seasons, nearly all melon fields in the Imperial Valley of California were surveyed for CYSDV incidence over a three year period, and whiteflies from fields were tested for CYSDV. During this period, CYSDV incidence in the fall crop was nearly 100% each year, resulting in a dramatic reduction in fall production and yields. In contrast, incidence in spring melons was initially low and limited to a small number of fields in 2007, but increased to 63% of fields by spring 2009, indicating establishment in native vegetation and a potentially increasing threat to the spring crop. A select set of weed and crop host plants common in the region were evaluated to determine how much CYSDV accumulates in different source plants on which whiteflies feed, how this relates to whitefly transmission of CYSDV to crop plants, and subsequent accumulation of virus in melons. Considerable variability was found among different source plant species for both virus accumulation and transmission. Cucurbit (melon, squash, and related weeds) host plants exhibited the highest CYSDV levels, were efficient as sources for transmission, and demonstrated an association between virus level in source plants and transmission. Most non-cucurbit hosts, however, accumulated significantly lower levels of CYSDV and varied in transmission efficiency. More importantly, CYSDV levels in some non-cucurbit source plants, specifically bean and shepherds purse, were not correlated with transmission, demonstrating additional environmental or physical factors influence transmission of CYSDV. These results illustrate the importance of evaluating multiple factors that may contribute to determining whether a virus host is an effective reservoir for transmission to crops.

Technical Abstract: Cucurbit yellow stunting disorder virus (CYSDV; genus Crinivirus, family Closteroviridae) was identified in the large melon production region of the American Desert Southwest during the Fall of 2006, and is now firmly established in the region, where it is transmitted efficiently by the sweet potato whitefly, Bemisia tabaci MEAM1 (also known as biotype B). Nearly all cucurbit fields in the Imperial Valley of California were surveyed for CYSDV incidence over a three-year period, and whiteflies from the fields were tested for CYSDV in order to evaluate spread and establishment of the virus during the Spring and Fall melon seasons. CYSDV incidence in the fall crop was nearly 100%, resulting in a dramatic reduction in Fall production and yields. In contrast, incidence in Spring melons was initially low and limited to a small number of fields in 2007, but increased to 63% by Spring 2009, indicating establishment in native vegetation and a potentially increasing threat to the Spring crop. A select set of weed and crop host species common in the region were evaluated to determine the ability of CYSDV to accumulate in each, and the relationship between virus level in source plants with transmission by SPWF whiteflies and subsequent accumulation in cucurbit test plants. Considerable variation was found in virus accumulation and transmission among source plant species. Cucurbits had the highest CYSDV titers, were efficient sources for transmission, and demonstrated an association between virus level in source plants and transmission. Non-cucurbit hosts, had significantly lower titers of CYSDV and varied in transmission efficiency. CYSDV levels in some non-cucurbit source plants, specifically bean (Phaseolus vulgaris) and shepherd’s purse (C. bursa-pastoris), were not correlated with transmission, demonstrating additional environmental or physical factors influence transmission of CYSDV. These results illustrate the importance of evaluating multiple factors that may contribute to determining whether a virus host is an effective reservoir for transmission to crops.