5 things you need to know about the Q-biotype whitefly

Growers from 26 different states from California to Maine have reported instances of the Q-biotype whitefly to local extension agencies and the United States Department of Agriculture (USDA).

This particular biotype of Bemisia tabaci whitefly is not the same as the A-biotype and B-biotype species that growers may be accustomed to seeing. And although not a new pest, the Q-biotype’s recent increased presence, which has now also been spotted in outdoor settings in Florida, has proven to be challenging for growers to handle effectively for a number of reasons.

Here’s what you should know about the pest: 

1. The Q-biotype was first discovered in 2005.

The first time Q-biotype B. tabaci was first identified in greenhouse production was about 11 years ago. However, according to a fact sheet from University of Florida’s Institute of Food and Agricultural Sciences UF/IFAS, it has recently been detected outside a greenhouse setting. “As a consequence [of the Q-biotype’s outdoor presence], there is cause for increased vigilance both in ornamental nurseries and commercial vegetables where it potentially could cause a significant economic loss,” according to the UF/IFAS fact sheet.

2. Q-biotype whiteflies look the same as other common whiteflies.

While observing the Q-biotype in a greenhouse or nursery, it may be impossible to differentiate it from the B-biotype whitefly. “Physically, morphologically, it is really no different,” says Mark Brotherton, Portfolio Leader at SePRO. The only way to tell one from the other is via laboratory analysis – a test that can evaluates genetic markers, which can be done at these two locations:

Dr. Pratibha Srivastava

Division of Plant Industry

Florida Department of Agriculture and Consumer Services

Gainesville, FL

352-395-4740

Pratibha.srivastava@freshfromflorida.com

Dr. Cindy McKenzie

U.S. Horticultural Research Laboratory

Fort Pierce, FL

772-462-5917

Cindy.mckenzie@ars.usda.gov

3. It’s built up resistance to many insecticides on the market.

Perhaps the most troublesome element to the Q-biotype whitefly is the difficulty in effectively control it with commonly used insecticides.  The Q-biotype is resistant to a number of insect growth regulators (IGRs), pyrethroids and neonicotinoids. “If the insect has developed resistance to a specific chemistry, that product is just not going to provide effective control,” Brotherton says, even at high label application rates. However, growers have noted that the Q-biotype has not yet developed resistance to Rycar, a fairly new chemistry to the market that acts as an immediate stop-feed until the pests’ eventual death, and also reduces viral transmission.

“There have not been any documented cases of resistance to Rycar, to date,” Brotherton says, noting that following the label directions will significantly reduce the chances of developing resistance. “You’ll want to make sure you rotate Rycar with other chemistries, and you want to limit it to two applications per crop cycle,” he adds.

4. Q-biotypes can be twice as likely to carry devastating diseases.

Compared to the B-biotype whiteflies, the Q-biotype whitefly has a higher chance of being a virus vector – meaning, it can carry viruses to and from infected plants, according to a report from UF/IFAS in June. The Q-biotype is known for spreading common viruses, such as the tomato spotted wilt virus (TSWV).

“The danger with this is that there’s no ‘cure’ or eliminating of a virus once you have a viral infection. That could be completely devastating to your crop to the point where you’re going to throw out your entire crop,” he says.

5. It will feed on a broad range of host plants.

Similar to the B-biotype whitefly, Q-biotypes are not picky about which plants they choose. But there are certain crops that they are more prone to infesting, such as hibiscus, lantana and poinsettia, etc. “As with most insect pests they have their favorite plant species to feed on. However due to the broad range of potential host plants, whiteflies may be present throughout the greenhouse.

To learn more about how to prevent and control whiteflies, listen to our podcast with SePRO’s Mark Brotherton. 

Photo courtesy of SePRO