Pesticide Resistant Whitefly Poses Threat to U.S. Crops

Dan Environment, General, Industry News Release

Pesticide Resistant Whitefly
Fruit and Vegetable growers are raising concerns over an invasive whitefly that is resistant to pesticides and carries crop-devastating viruses. The Q-biotype whitefly was found outdoors within the U.S. for the first time this spring in Florida. Its discovery outdoors comes more than a decade after it was first found in a U.S. retail nursery in Arizona. Since 2005, the whitefly has also been found in about two dozen U.S. states, but only in greenhouses. The Q-biotype whitefly is already considered a major invasive pest worldwide. Researchers say pest poses a serious threat to crops such as tomatoes, beans, squash, cotton and melons. Whiteflies draw fluid out of a plant’s leaves, and excrete a sticky residue that allows fungus to grow, turning the leaves black and making it harder for them to photosynthesize. University of Florida researchers say the whiteflies have been found in more than 40 locations across the state, including residences, wholesale nurseries and retail plant outlets.

From the National Association of Farm Broadcasting news service.

From: University of Florida/IFAS Mid-Florida Research and Education Center


Biotype-Q or BIOTYPE-B?

sl-white fly-adult-UF-IFASThis could be either one. They look identical!

Unfortunately, we have a developing whitefly issue in Florida. We are having major issues managing 2 biotypes in a number of areas in South Florida. Both biotypes are referred to as Bemisia tabaci. The Q biotype has been detected in a number of landscapes in Palm Beach County.  This is the VERY FIRST TIME it has been found in a landscape or outside a greenhouse or nursery since it was found on an ornamental plant in a greenhouse many years ago (2004-2005). This is extremely troubling considering the issues we have with many of the tools we use to manage whiteflies.

Bemisia tabaci (Gennadius) feeds on more than 900 host plants and vectors over 111 plant virus species and is considered to be a major invasive species worldwide. The taxonomic status of B. tabaci remains debated between 36 previously identified biotypes and the newly proposed 24 discrete species and they can only be identified by performing genetic analysis. Losses in agricultural production have increased owing to B. tabaci as new, more virulent and less pesticide-sensitive cryptic species have spread to all continents except Antarctica. Very few countries have escaped its cosmopolitan distribution and subsequent establishment of at least one of the B. tabaci cryptic species. The two most invasive members of the cryptic species complex posing the greatest threat to growers are Middle East –Asia Minor 1 (MEAM1) and Mediterranean (MED) (commonly known as biotypes B and Q respectively).

After the introduction of MEAM1 into the United States around 1985, unprecedented losses began occurring on poinsettia in the late 1980s in Florida, followed by high infestations in field-grown tomato crops. MEAM1 rapidly spread across the southern United States to Texas, Arizona and California, where extreme field outbreaks occurred during the early 1990s on melons, cotton and vegetable crops. Losses exceeded more than 500 million dollars in one year.

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Image credits:  (Top Left) Whitefly-Wikipedia Commons. (Center) Bemisia tabaci white fly courtesy of University of Florida/IFAS.