Whitefly-transmitted Viruses in Cucurbit Crops

Survey of Whitefly-transmitted Viruses in Watermelon and Other Cucurbit Crops in Alabama, Louisiana, and Mississippi

Photo: Chlorosis on leaves near the crown is visible down the center of rows in a melon field in California with plants infected with both cucurbit chlorotic yellows virus and cucurbit yellow stunting disorder virus. Credit: W. M. Wintermantel, USDA-ARS.

Project Summary: A number of whitefly-transmitted viruses, including cucurbit leaf crumple virus, cucurbit yellow stunting disorder virus, cucurbit chlorotic yellows virus, and squash vein yellowing virus, are able to infect and cause losses in melons and other cucurbit crops. These and other insect viruses, which cause similar yellowing symptoms, are known to occur in the larger melon and watermelon producing states. Appropriately, recent research on these viruses has been largely focused on those states. However, natural and manmade activities may lead not only to the introduction of viruses to new areas but also to the expansion of the current range of viruses. This is evidenced by the recent spread of cucurbit viruses between California and Florida and from Florida into Georgia and South Carolina. The threat these viruses pose to melon and watermelon production extends to watermelon production in all watermelon-producing states, and the current status of these viruses in states that have not been the focus of the recent study is deserving of exploration, particularly for the benefit of watermelon and other cucurbit producers. The purpose of this project is to determine the occurrence of the major whitefly-transmitted viruses known to infect cucurbits, the whitefly species, and biotypes that occur in areas where those viruses are found in some of the lesser-studied watermelon-producing states, specifically Alabama, Louisiana, and Mississippi, and to educate watermelon and other cucurbit growers and stakeholders on the importance, recognition, and management of these viruses. This will be accomplished through a collaborative effort between plant pathologists at the USDA-ARS, Auburn University, Louisiana State University, and Mississippi State University.  Samples of watermelon and other cucurbit crops, as well as whiteflies collected during field surveys, and additional samples provided by grower collaborators in Alabama, Louisiana, and Mississippi will be tested for the presence of the known whitefly-transmitted viruses affecting watermelon and other cucurbits in the U.S. Whitefly species and biotype will also be assessed. Viruses will be identified using an established molecular detection system involving multiplex RT-PCR and PCR to amplify specific nucleic acid sequences unique to each virus and gel electrophoresis to visualize amplified products, which allows for the identification and differentiation of the target viruses present in a sample. Project collaborators will develop traditional and web-based educational materials, including a fact sheet, photo guide, and video presentation, that will be used, alone or in conjunction with in-person Extension training to educate watermelon growers and stakeholders in each state on the known whitefly-transmitted viruses affecting watermelon and other cucurbits in the U.S. Results of the project will lead to the development of best management practices for virus disease management in these states and will be presented, along with educational materials describing those management practices, to growers and stakeholders following completion of the project. In summary, the information and knowledge gained from this project will help researchers and Extension specialists determine the threat whitefly-transmitted viruses in cucurbits pose to watermelon growers in Alabama, Louisiana, and Mississippi and develop grower resources that can be used to evaluate risk and mitigate disease in these as well as other watermelon-producing states. Note: This project started in 2020 and will be continuing through 2022.

Training Video/Presentation:

Factsheet: Whitefly-transmitted and Yellowing Viruses in Watermelon and Other Cucurbit Crops

Photo Guide: A Photo Guide to Whitefly-transmitted and Yellowing Viruses in Watermelon and Other Cucurbit Crops

Grower-Collaborator Registration: Learn what it means to be a grower-collaborator and volunteer to be a grower-collaborator in Alabama, Louisiana, or Mississippi here.

Project Collaborators:

• Dr. Rebecca A. Melanson (State Project Leader - Mississippi)

Mississippi State University Extension Service

rebecca.melanson@msstate.edu

(601) 857-2284

• Dr. Edward Sikora (State Project Lead - Alabama)

Alabama Cooperative Extension System - Auburn University

sikorej@aces.edu

(334) 332-7433

• Dr. Rajghuwinder (Raj) Singh (State Project Lead - Louisiana)

Louisiana State University Agricultural Center

RSingh@agcenter.lsu.edu

(225) 578-4562

• ​Dr. William M. Wintermantel (Project Leader)

USDA-ARS

bill.wintermantel@usda.gov

Acknowledgement: This project is funded by the National Watermelon Association. Any opinions or recommendations expressed on this webpage do not necessarily reflect the views of the National Watermelon Association.