Local whitefly populations are quietly becoming abundant on spring melons. As temperatures continue to increase on maturing crops, feeding damage from whitefly nymphs should be a primary concern on all melon types. Honeydew and sooty mold contamination on fruit of cantaloupes, mixed melons and watermelons can significantly reduce quality and marketability. Now that whitefly adults are becoming noticeable in a number of locations, PCAs should be diligent in their monitoring and sampling. Our research has shown that to prevent melon yield and quality losses, a foliar insecticide treatment should be applied when on a threshold of 2 adult whiteflies per leaf is exceeded when averaged across an entire melon block. By timing sprays based on the adult threshold, immature populations should just be starting to colonize and applying foliar sprays at this stage in population development has been shown to significantly reduce the chance of yield / quality loss during harvest. This threshold applies for the use of recommended IGRs (Vetica, Courier, Knack, Oberon), foliar applied neonicotinoids (Assail, Venom, Scorpion) and Exirel (diamide). For more information, go to these documents on 1) IPM and Whitefly Management, 2) Whitefly Action Thresholds and 3) Whitefly Control Options. Also, be aware of honey bees and other pollinators in or around melon fields. If bees are present, be sure to carefully read labels and determine the products bee safety before applying any pesticide in a melon field.
Note: Cucurbit Yellow Stunting Disorder Virus (CYSDV) is not generally known to be yield limiting on spring melons. However, our local research indicates that fall melons are at greater risk of CYSDV infection when planted in areas where CYSDV symptoms were found on spring melons. Thus, keeping whitefly populations low on spring melons reduces dispersal to cotton, other alternative crops and weeds later in June and July. Ultimately, this can reduce the risks of high whitefly numbers and CYSDV on fall melons.

Name this Insect Pest.
First person to email John or AZVegIPM-Team@email.arizona.edu with the answer gets a new UA Veg IPM cap!

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

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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.