The latest Arizona Vegetable Integrated Pest Management Update from the University of Arizona (UA) Cooperative Extension in Yuma, Ariz. released July 10, 2012.

Whitefly-CYSDV management meeting July 19

By John Palumbo, UA Research Scientist and Extension Specialist

Planting of melons is less than a month away. Pest control advisers and growers should begin finalizing insect management programs.

Whiteflies and cucurbit yellow stunting disorder virus (CYSDV) continue to cause serious economic problems on fall melons and have been increasingly difficult to manage. In response to this on-going problem, a considerable amount of research has been directed to find cost-effective solutions to the management of whitefly adults and the subsequent transmission of the virus.

New management information is particularly important now since endosulfan will not be available to melon growers this next fall.

The UA will hold a meeting at the Yuma Agricultural Center (YAC) July 19, 2012 from noon to 3 p.m. (lunch included) to provide an update on the most recent research on whiteflies and CYSDV on melons.

This update will provide new information on insecticide alternatives evaluated as replacements for endosulfan for adult whitefly control. In addition, virus incidence on spring and fall melons over the past five years will be discussed.

The UA’s latest recommendations for whitefly management and CYSDV suppression on fall melons will be discussed.

In association with the research update, we will hold our annual Melon Crop Losses Workshop where PCAs can provide information pest losses, control costs, and control information for spring melons in 2012. The UA has conducted crop loss surveys for melons over the last eight years.

We invite PCAs and growers to attend the workshop and help us better understand the impact that insects, diseases, and weeds have on our local melons crops.

Click on this link for more meeting information - Whitefly / CYSDV Control Update & Melon Crop Losses Workshop.

Click on this link to listen to John.

Remember: when in doubt – scout.

Contact Palumbo: (928) 782-3836 or

Summer preplant soil flooding as a Sclerotinia lettuce drop management tool

By Mike Matheron, UA Extension Plant Pathologist

Lettuce disease management is likely the last thing on the mind of a PCA or grower as we enter the hottest part of the year in the desert southwest region of Arizona. However, this is the perfect time to perform pre-plant soil flooding in fields with high levels of Sclerotinia drop this past season.

How can soil flooding help manage a disease that will not be a problem for several more months?

First, the two fungi that cause lettuce drop, Sclerotinia minor and Sclerotinia sclerotiorum, carry over in fields between crops of lettuce as structures called sclerotia. These fungal propagules function similar to seeds and remain dormant until germination in cool, moist soil and infect lettuce plants.

Many sclerotia will decay naturally over time. However, sufficient numbers can remain in a field after one or more years to cause lettuce drop when a planting is established. If virtually all sclerotia in a field could be destroyed, then this field would no longer be a source of the Sclerotinia lettuce drop pathogens.

This is where summer preplant soil flooding comes in. Past research conducted at the UA’s YAC demonstrated a three-week period of flooding in the summer destroyed all sclerotia of S. minor and S. sclerotiorum present in soil.

Some growers in the Yuma area have used pre-plant soil flooding to successfully manage Sclerotinia lettuce drop in fields chronically affected by this disease.

Click on this link to listen to Mike's update.

Contact Matheron: (928) 726-6856 or

Online continuing education classes

By Barry Tickes, UA Area Agriculture Agent

The Weed Science Society of America (WSSA) has a five-module training program on herbicide resistant weeds offered online by Penton Media/Western Farm Press for continuation credit for PCAs, growers, and other licensees.

There is no charge for the course and it is accredited for two continuing education hours by the Arizona Department of Agriculture and the California Department of Pesticide Regulation. It is also accredited for two hours of soil and water credit for Certified Crop Advisers.

The course called “Current Status of Herbicide Resistance in Weeds” is divided into five modules including: Section 1 - Current Status of Weeds; Section 2 - How Herbicides Work; Section 3 - What is Herbicide Resistance; Section 4 - Scouting After Herbicide Application and Confirming Herbicide Resistance; and Section 5 - Principles of Managing Herbicide Resistance.

The course can be accessed online at

To earn continuing education hours for the program you must complete a quiz. When you pass the course with a passing grade of at least 70 percent, Penton will notify the agency that manages your license that you have completed the course and you will receive a certificate for your records.

You can download the course to review and study offline. You can take the quiz as many times as you like.

This is one of more than 25 continuing education courses offered by Penton Ag Media for PCAs, private applicators, aerial applicators, and qualified applicators.

Most of the courses are provided free of charge and are sponsored by several agricultural suppliers. Some courses are no longer sponsored and cost $50 per course when taken for credit.

Other weed management courses include: Weed Management in Orchards and Vineyards; Managing Spray Drift to Minimize Problems; Weed Resistance Management in Agronomic Row Crops and Trees, Nuts, and Vines; Weed Resistance Management in Cotton, and Weed Resistance Management in Non-Crop Industrial, Turf, and Ornamental Sites.

Arizona is one of only four states without a reported case of herbicide resistance. Each state that borders Arizona has documented herbicide resistance cases. This is a growing problem which can be avoided.

Contact Tickes: (928) 580-9902 or

Click this link to listen to Barry.

Please note this correction: A previous article in this advisory stated that the Eptam label specifies “Do not plant cotton or crops not listed on the Eptam label for 90 days after application.” Actually, this has been changed to now read, “Do not plant crops not on the Eptam 7E label for 45 days after application.” We regret the error.