Sep 23, 2011 – Gumbo Limbo Is In Limbo
QUESTION:
How do you deal with the Spiraling Whiteflies that are attacking the Gumbo Limbo trees?
ANSWER:
This is a newcomer to Florida with the impressive name of the Gumbo Limbo Spiraling Whitefly, although an alternate name is the Rugose Spiraling Whitefly, and it attacks far more plants than just gumbo limbo, including oak, palm, olive, and others. The name comes from the distinctive spiraling pattern created as the female whitefly deposits her eggs on the surface of a leaf. Otherwise the story for this new species seems to be fairly similar to many other whiteflies, according to fact sheets and articles from the Univ. of Florida. It creates a lot of honeydew which then leads to the growth of sooty mold, it creates large amounts of white waxy material on the leaves, and while it is feeding on the plants it rarely does much serious damage to larger, healthy trees. The primary concern is an aesthetic one, which does not demean the importance of yet another exotic import.
It was only in 2009 that this whitefly was first discovered in the Miami area of Florida, and yet already specialists have noted at least one parasitic wasp attacking the whitefly. This gives them hope that parasites and predators that specialize in other whiteflies may do a good job on this one. In California the awful Ash Whitefly of the 1990's was successfully beaten back with an importation of a parasitic wasp, so the tiny parasites sometimes do a very good job.
Insecticides can be very helpful, but the problem with whiteflies is all of that wax, which repels water-based sprays applied to the leaves. The most susceptible stage of the whitefly is the crawler stage, which is the first stage out of those eggs. At this point it is mobile and has not created all of the wax to coat itself, and topically applied products can more easily contact the bug. If you choose to do foliar sprays they should be spaced 7-10 days apart to try to get the crawlers before they move onto their next and more resistent stages. Here you could use any insecticide labeled for whitefly on ornamental plants. One of these could be a low-impact material like a summer horticultural oil or soap. These need to contact the insects directly and leave no residual effect. For all foliar sprays the treatment must concentrate on the LOWER surfaces of the leaves, as this is where the eggs are deposited and the whiteflies spend nearly all of their time.
More effective may be systemic insecticides that actually get INTO the foliage of the plant where the active ingredient can then be sucked up by the feeding whitefly. The systemics also tend to last much longer than foliar applied contact materials as they are protected within the leaf tissue. A product like imidacloprid (e.g. Merit) can be applied to the soil around the tree and taken up by the roots and transported to the foliage. On many plants this provides season-long control of insects such as aphids, and it may do well on whiteflies too. But, this is still early enough in the battle with this pest that the Univ. of Florida has not published any specific findings on what works or does not.
View past Ask Mr. Pest Control questions.
How do you deal with the Spiraling Whiteflies that are attacking the Gumbo Limbo trees?
ANSWER:
This is a newcomer to Florida with the impressive name of the Gumbo Limbo Spiraling Whitefly, although an alternate name is the Rugose Spiraling Whitefly, and it attacks far more plants than just gumbo limbo, including oak, palm, olive, and others. The name comes from the distinctive spiraling pattern created as the female whitefly deposits her eggs on the surface of a leaf. Otherwise the story for this new species seems to be fairly similar to many other whiteflies, according to fact sheets and articles from the Univ. of Florida. It creates a lot of honeydew which then leads to the growth of sooty mold, it creates large amounts of white waxy material on the leaves, and while it is feeding on the plants it rarely does much serious damage to larger, healthy trees. The primary concern is an aesthetic one, which does not demean the importance of yet another exotic import.
It was only in 2009 that this whitefly was first discovered in the Miami area of Florida, and yet already specialists have noted at least one parasitic wasp attacking the whitefly. This gives them hope that parasites and predators that specialize in other whiteflies may do a good job on this one. In California the awful Ash Whitefly of the 1990's was successfully beaten back with an importation of a parasitic wasp, so the tiny parasites sometimes do a very good job.
Insecticides can be very helpful, but the problem with whiteflies is all of that wax, which repels water-based sprays applied to the leaves. The most susceptible stage of the whitefly is the crawler stage, which is the first stage out of those eggs. At this point it is mobile and has not created all of the wax to coat itself, and topically applied products can more easily contact the bug. If you choose to do foliar sprays they should be spaced 7-10 days apart to try to get the crawlers before they move onto their next and more resistent stages. Here you could use any insecticide labeled for whitefly on ornamental plants. One of these could be a low-impact material like a summer horticultural oil or soap. These need to contact the insects directly and leave no residual effect. For all foliar sprays the treatment must concentrate on the LOWER surfaces of the leaves, as this is where the eggs are deposited and the whiteflies spend nearly all of their time.
More effective may be systemic insecticides that actually get INTO the foliage of the plant where the active ingredient can then be sucked up by the feeding whitefly. The systemics also tend to last much longer than foliar applied contact materials as they are protected within the leaf tissue. A product like imidacloprid (e.g. Merit) can be applied to the soil around the tree and taken up by the roots and transported to the foliage. On many plants this provides season-long control of insects such as aphids, and it may do well on whiteflies too. But, this is still early enough in the battle with this pest that the Univ. of Florida has not published any specific findings on what works or does not.
View past Ask Mr. Pest Control questions.
