Georgia Whitefly Populations Explode, Troubling Vegetable Growers

Georgia Whitefly Populations Explode, Troubling Vegetable Growers

Adult whitefly is feeding on a tomato leaf. Photo credit: Saioa Legarrea, University of Georgia.

Adult whitefly is feeding on a tomato leaf. Photo credit: Saioa Legarrea, University of Georgia.

Whitefly populations in South Georgia have exploded over the past several weeks, troubling vegetable producers during the fall growing season, according to University of Georgia horticulturist Tim Coolong.

Coolong said growers must be up-to-date on spray programs, though combating whitefly populations of this magnitude will still be difficult. In some cases it might be impossible to stop whiteflies before they spread viruses.

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Whiteflies feed on plants by sucking juice out of the leaves. They can transmit viruses that are devastating to vegetable crops. Babu Srinivasan, an entomologist at the University of Georgia Tifton Campus, said that the silvering of leaves in cucurbits is a problem associated with feeding damage. The flies suck chlorophyll and other cell contents from leaves, which could reduce fruit set.

“Aside from silvering of leaves in cucurbits, whiteflies cause irregular ripening of tomatoes, which reduces market value and is only evident after harvest,” Srinivasan said. “The most important thing, however, is that they can actually transmit viruses.”

“Because they have multiple hosts, are very small and capable of flying — and the fields are located very close to each other — there is no practical way to completely get rid of them,” Srinivasan said.

There are some ways to mitigate feeding damage, according to Srinivasan. He said that growers could use reflective mulch to make it harder for the whiteflies to land on the plants. The seedlings can also be drenched with insecticides before being planted.

Srinivasan said that climate and weather patterns are huge reasons why whitefly populations are so high. He said the warm winter and lack of rainfall in early summer could be reasons for this explosion.

Source: University of Georgia

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David Headrick says:

Whitefly feeding has been incorrectly represented in this article. Both nymphs and adults have stylets that are inserted into leaves and pierce the vascular bundles to suck out plant sap or the phloem. They do not suck the juices from leaves, nor do they suck chlorophyll or cell contents. The cells are not fed on and reduced fruit set may be a result of loss of phloem as opposed to direct feeding. Leaf hoppers are able to feed on cell contents and cause direct feeding damage to leaves and fruit, the resulting silvering from leaf hopper damage is referred to as “blight” or “hopper burn”. Whiteflies may also transmit more than just viruses. The article incorrectly implies that the silvering of leaves is due to the whiteflies removing cell contents. The silvering is due to virus-like disorders that cause an internal separation of the leaf tissues. The use of reflective mulches is typically impractical in the application described above, it’s expensive and needs to be free of debris or cover in order to work. Once the plastic mulch layer is down follow up cultivation is impossible.

indra effendi says:

David Headrick, may I know your email, I would like to ask some question about virus gemini muskmelon. We have done two different demo trial which is one do not suffer from virus at all with the same non resistant variety in indonesia, but I dont know the answer, can we discuss more private discussion…