Whitefly Update
A LETTER TO ORNAMENTALS GROWERS
FROM THE AD HOC WHITEFLY TASK FORCE
Based on early reports, 2007 may be another challenging year for whitefly management. Whiteflies have been detected in some rooted cuttings shipments, and hot dry conditions have promoted a greater than normal buildup of whiteflies on field crops in parts of the southeastern United States.
The Ad Hoc Whitefly Task Force, made up of state and federal regulators, representatives of the ornamentals, cotton and vegetable industries, and leading scientists, has been working together to develop effective whitefly management programs since 2005. The success of this effort has serious economic implications for U.S. agriculture, and depends in part on you - the ornamentals grower.
A good whitefly management program must have two goals. First, of course, is to help growers produce a high quality, salable crop for the final consumer. Second, but of equal importance, is preserving the chemical tools that agriculture uses to manage whiteflies. If we do not maintain the viability of effective chemical tools, it will be difficult for many growers to produce a salable crop. Consequently, the wise use of chemicals, through a scientifically based IPM program, is essential in this 21st Century. Europe has seen, and is suffering from, the results of overspraying. Insecticide misuse in the United States may result in silverleaf whitefly populations that cannot be controlled. It is important to remember that the Q-biotype whitefly is already resistant to a number of products commonly used. Chemical overspray could easily lead to B-biotype resistance.
The Task Force asks you to collaborate with us in this effort. It's not just about the challenges posed by the Q-biotype. It's about avoiding resistance development in any whitefly population.
What should commercial growers be doing?
1. Scout - essential. Inspect your crops at least weekly. Don't let the whiteflies get ahead of you, or your treatment options will be more limited.
2. Exclude or isolate. If at all possible, try to exclude whiteflies from your growing facility with screening material, and if possible, isolate the facility so that workers have to enter through an anteroom.
3. Practice good sanitation - essential. Keep weeds down, maintain good growing practices.
4. Inspect incoming shipments, and isolate if necessary. All of the major propagators are cooperating in this program, so you should not be receiving undue numbers of whiteflies. Because zero-tolerance is NOT the goal for anyone, you may see a whitefly or two when your shipments arrive. That's normal, and means that your propagator (or rooting station) is probably following good management practices. However, if you see many whiteflies on incoming shipments, keep those shipments separate from your other crops until they have been treated. And contact your propagator or rooting station - inform them about the situation. Ask whether they are biotyping their whiteflies, if they are monitoring resistance levels in their whitefly populations, and if they are following the Task Force's recommended Management Program.
5. Watch your neighbors' fields. If you're near cotton or vegetable fields, you may see whiteflies migrate to your greenhouse at the end of their season, and you'll have to deal with it. If you know when those seasons are, you'll be better prepared.
6. Study and implement the "Management Program for Whiteflies on Propagated Ornamentals" recommended by the Task Force. It's available at http://www.mrec.ifas.ufl.edu/LSO/bemisia/bemisia.htm. This program is based on the best scientific data developed to date by the Whitefly Task Force scientists. Do not rely on just one or two effective products, but instead integrate products with different modes of action to decrease the potential for developing resistance.
7. If you have control problems: contact your propagator, your local extension agent or university expert. Follow our "Whitefly Management Program", and get your whiteflies biotyped. The biotyping process is fast, and information will be kept absolutely confidential. Knowing which biotype you are dealing with will help you choose the most effective control products. (The Management Plan provides a list of addresses to which samples may be sent for biotyping.)
In the United States, the potentially impacted industries, federal and state governments, and scientists have cooperated in the aggressive, cooperative whitefly management effort to help growers produce a salable crop and minimize the likelihood of developing resistant whiteflies. You are an essential part of that effort.
REMEMBER: Q-BIOTYPE WHITEFLIES ARE A DOCUMENTED THREAT, BUT THERE IS ALSO EVIDENCE THAT B-BIOTYPE ARE DEVELOPING RESISTANCE AS WELL. Only by working cooperatively, wisely, and together can agriculture solve this problem.
PLEASE DON'T BE PART OF THE PROBLEM: BE PART OF THE SOLUTION!
Related
BIOTYPING INFORMATION
The following laboratories have agreed to receive whitefly samples and determine biotype. The results belong to the sender. We would, however, like to request that the following information be available to the Whitefly Taskforce:
- Date collected
- Crop
- Location: at the very least we would like state and county.
- Control history, if possible
- pesticides used
- control or failure
There are a number of specifics concerning how one collects a sample and preserves it for evaluation. For these specifics you MUST contact the individual laboratories.
Cindy McKenzie, Ph.D.
Research Entomologist
USDA, ARS, US Horticultural Research Laboratory
2001 South Rock Road
Fort Pierce, FL 34945
E-mail: cmckenzie@ushrl.ars.usda.gov
Frank J. Byrne, Ph. D.
Assistant Researcher
Dept of Entomology
University of California, Riverside
3401 Watkins Drive
Riverside, CA 92521
Phone: 951.827.7078
E-mail: frank.byrne@ucr.edu