Planting of fall melons is rapidly approaching and as growers begin to prepare local fields for fall planting they should be considering the threat of cucurbit yellow stunting disorder virus (CYSDV). This whitefly transmitted crinivirus was first identified in desert melons in the fall of 2006 where widespread infection on cantaloupes, honeydews and other melons occurred. CYSDV can cause significant losses in melon fruit yield and quality, and without question, desert melon crops have been seriously affected by this virus. Melon IPM has also been impacted by CYSDV where insecticide usage on fall melons has increased significantly. Over the past ten years we have been studying the epidemiology of CYSDV and trying to understand the complex relationships between the virus, vector and our local cropping system. Our ultimate goal is to develop practical approaches for reducing CYSDV impact on fall melon production. In addition, we continue to develop new information on chemical control of the whitefly vector (Bemisia whitefly adults). Last fall, whitefly populations were light and CYSDV incidence on fall melons was at an all-time low. Thus far, whitefly numbers this spring and summer have been relatively light compared to previous years and the incidence of CYSDV was low on spring melons. How the low numbers translate into virus incidence on the fall melon crop is unknown. However, our experience suggests that growers should anticipate CYSDV to be present. Further, given the aggressive management programs that PCAs and growers are now using, it will be interesting to see how CYSDV impacts melon production this fall. Our research to date suggests that fall melons produced near cotton or near areas where spring melons were recently produced are at the highest risk of infection. When possible, growers should attempt to isolate fall plantings as far away as possible from these sources of whiteflies and CYSDV. Growers forced to plant fall melons near these crops should be vigilant in minimizing adult whitefly infestation levels with insecticides during pre-bloom growth stages. To view a summary of the status of CYSDV in Yuma County and guidelines for management visit 2016 Guidelines for Whitefly and CYSDV Management on Melons.

Name this Insect Pest. - Swede Midge


Cartoonist: Juan Pena
Hey John, did you paint your truck? No Bill . . . it’s the whitefly!

Remember, When in Doubt . . . . . “SCOUT”

Click picture to listen to John’s update

To contact John Palumbo go to:jpalumbo@ag.arizona.edu

For questions or comments on any of the topics please contact Marco Pena at the Yuma Agricultural Center.
College of Agriculture, The University of Arizona, Tucson, AZ.