Location: Crop Improvement and Protection ResearchTitle: Emergence of new whitefly transmitted viruses affecting cucurbit production in the southwestern United States
Submitted to: International Plant Virus Epidemiology Symposium
Publication Type: Abstract Only
Publication Acceptance Date: 1/29/2019
Publication Date: 5/13/2019
Citation: Wintermantel, W.M., Gilbertson, R.L., McCreight, J.D. 2019. Emergence of new whitefly transmitted viruses affecting cucurbit production in the southwestern United States. International Plant Virus Epidemiology Symposium, May 13-17, 2019, Seoul, Republic of Korea.
Technical Abstract: Cucurbit production in the southwestern United States and northwestern Mexico has been severely impacted by Cucurbit yellow stunting disorder virus (CYSDV; genus Crinivirus; family Closteroviridae) since its emergence in 2006. This has resulted in the elimination of fall production in the Imperial Valley of California. In response, an aggressive effort to identify sources of resistance against CYSDV and to incorporate this resistance into melon cultivars was initiated. Management of CYSDV in the region is compounded by high populations of whitefly (Bemisia tabaci MEAM1) and the prevalence of weed and alternate crop hosts, e.g., alfalfa. Development of cultivars with resistance to CYSDV was progressing well; until 2014, when Squash vein yellowing virus (SqVYV; genus Ipomovirus, family Potyviridae) was identified in the region and, in 2018, Cucurbit chlorotic yellows virus (CCYV; genus Crinivirus) was identified and subsequently detected in samples collected since 2014. The presence of CCYV has complicated CYSDV resistance breeding, because both viruses produce similar interveinal yellowing and chlorotic spotting symptoms in melon and watermelon. Although CCYV is often less competitive in mixed infection with CYSDV, it remains to be determined if this pattern holds in the U.S. desert southwest, and what impact the presence of an additional ipomovirus may have on accumulation of the criniviruses in resistant cultivars and disease development.