Whitefly Watch

Whitefly Watch

Whitefly control has been a challenge this year, the Society of American Florists (SAF) reports. In order to avoid serious problems later in the season, scientists in the field and on the Ad Hoc Whitefly Task Force advise growers to watch their spray programs carefully to be sure they are working.

Resistant whiteflies, and/or increased numbers of whiteflies, have been reported by growers in several parts of the United States. It is extremely important that growers who notice apparent resistance in whitefly populations send whitefly samples for biotype identification. The Q-biotype, first discovered in the United States in 2004, is resistant to many, but not all, of commonly used chemicals. Is the B-biotype developing stronger resistance as well? Only grower-scientist cooperation can provide that answer.


Samples can be sent to any of several labs with guarantees of anonymity, and no regulatory action will follow. But knowing which biotype a grower is facing can help in using the appropriate chemicals–and avoiding development of even more resistant whiteflies.

In 2005, SAF joined with representatives of the cotton and vegetable industries and with state and federal regulators to form the Ad Hoc Whitefly Task Force, which has worked since then to develop more data on best chemical use, grower education and inter-industry cooperation. Grower cooperation is essential if propagator, scientific research and other task force efforts are to succeed. Cooperation led to success in 2006 and it is imperative the trend continues in 2007.

For more information, please go to the “Management Program for Whiteflies on Propagated Ornamentals” site. It spells out actions growers need to take now. It also gives growers information on how and where to send samples for biotype identification. If you are having whitefly control problems, or think that you may notice some resistance in your whitefly populations, access the above program. Do not rely on one or two chemicals to try to fix the problem. Contact your Extension agent or local university expert for further advice. For more information, contact Lin Schmale.

SOURCE: Society of American Florists