Pest Alert: Q-Biotype Whitefly Spreading in Florida

Chris Beytes

Reports from Florida say that 2016 could be a challenging year for whiteflies down there, according to an email GrowerTalks received from SAF’s Drew Gruenberg on behalf of his organization, AmericanHort and the FNGLA (Florida Nursery, Growers and Landscape Association). The warning is primarily intended for Florida growers, but pests do spread, so it’s good for everyone to be aware.

Headlined thusly—

REPORTS ARE COMING IN ABOUT WHITEFLY MANAGEMENT PROBLEMS! INDUSTRY COOPERATION IS ESSENTIAL!!

—the red capital letters and multiple exclamation points grabbed our attention. Here’s their urgent warning and plea to the Florida industry:

Reports have come from the Florida Keys to Palm Beach County that whitefly populations in landscapes are reaching unprecedented levels and are not responding to pesticide applications: Biotype-Q has been found in four different communities (Palm Beach Gardens, Palm Beach Island, Boynton Beach and Boca Raton). [It is] the first time Biotype-Q has ever been found on plants outside a nursery or greenhouse.

University of Florida/IFAS researchers are working with USDA-APHIS, USDA-ARS, the Florida Department of Agriculture, and with growers and landscape professionals to manage the developing problem. SAF and AmericanHort are joining with the Florida Nursery, Growers & Landscape Association (FNGLA) and with the Florida Fruit & Vegetable Association (FFVA) in the effort. Cooperation by growers, landscape professionals and the public is essential.

Of the two major whitefly “biotypes,” the B-biotype has been present in the U.S. since the 1980s and is controllable by proper management in growing operations and in the landscape, although some resistance to pesticides is developing. The Q-biotype, first seen in the U.S. in 2005, is much more difficult to manage. Overspraying in an attempt to try to control the B-biotype may result in the spread of the Q-biotype, and the threat in Florida of Biotype-Q could be great for the commercial production of vegetables through spread of viruses.

Because new populations have built up resistance to chemicals, it is strongly recommended that suspected whitefly infestations be confirmed before chemically treating the insects, as it may be needless to spray pesticides. Testing is fast, free and confidential. See below for instructions.

Go to http://mrec.ifas.ufl.edu/lso/bemisia/bemisia.htm. This site contains the “Management Program for Whiteflies on Propagated Ornamentals” recommended by the Whitefly Task Force. Note that this program was developed for the production of plants in greenhouses and some of the materials are not registered for outdoor use. There is a separate list of materials registered for whitefly control in the landscape on this website, as well. Do not rely on just one or two effective products. Instead, rotate products with different modes of action to decrease the potential for whiteflies developing resistance.

It is essential that samples of dead whiteflies be sent immediately for genetic identification, which is free. Confidentiality will be preserved. This kind of identification will enable scientists to help track the spread of the Q-Biotype and will help growers use proper control programs to prevent further spread.

How to send a sample:

• Homeowners who suspect they have a whitefly infestation should immediately contact their University of Florida Extension county office. Offices may be found by going to http://sfyl.ifas.ufl.edu/map/index.shtml.

• Agricultural concerns, growers and landscape professionals may send samples for rapid identification directly to Dr. Cindy McKenzie at the USDA-ARS, as noted below.

• Infested leaves and dead insect specimen should be wrapped in a dry paper towel, placed in a sealable plastic bag and then in an envelope. If possible, freeze the sample overnight before transport. Do not transport live insects!

• Include collection information with the sample: date, location, type of vegetation affected, number of suspected whiteflies and, if possible, any information about pesticides used on the plant. This information is helpful to scientists tracking and advising on management of the pest.

Send directly by overnight mail to:

Cindy McKenzie, Ph.D.
Research Entomologist
U.S. Horticultural Research Laboratory, ARS-USDA
2001 South Rock Road
Fort Pierce, Florida 34945
(772) 462-5917 office
(772) 462-5911 lab

The letter concluded with information on how to get updates on the whitefly situation here: http://mrec.ifas.ufl.edu/lso/bemisia/bemisia.htm.

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