The invasion of the nasty critter is spreading fast. Here’s what you can do about it.
If your garden contains hibiscus or other plants you might be familiar with the Giant Whitefly or White Ash Fly. I’ve been fighting them for years and although I haven’t won the battle, I am making progress.
The fly, known by its scientific name of Aleurodicus Dugesii, is very small – about 4 millimeters in length – but they arrive in hordes. In some cases you might not even readily see the infestation because they tend to do their damage to the underside of hibiscus and other plants. But, left untreated you can have a hibiscus plant that is enveloped like a cocoon.
The fly looks like a tiny, white moth. Its origins are in Mexico and they arrived in the Southern California area in the 1990s. From there it has spread to other states and as far as Hawaii and nothing seems to be effectively stopping it. Hibiscus plants seem to provide its most ideal residence, but they can and do enjoy other plants and shrubs as well. The adults of the species love to lay their eggs on the underside of leaves – and they lay a lot of eggs. They excrete a waxy substance that forms layers of material until you have a thick, gooey and ugly scene that appears to be giant cobwebs covering your plant. They are also adept at sucking out the plant sap and killing leaves.
Here are some tips if the fly victimizes you.
Pull out infested leaves so they don’t spread. It is usually not highly effective but it’s a start.
Try cutting back the plant back to the ground to eliminate the source of the flies’ meals and spawning ground. You should combine this with some of the other following methods of control.
Try purchasing ladybugs as a counter-force to the ash fly. They may work as a natural predator although the ladybugs do tend to move elsewhere eventually and the fly does return. However, there is a lot to be said for biologically controlling the pests. Some other species, such as lacewings, lady beetles and wasps are said to be effective, but again they are hard to control in terms of keeping them on or around your own garden.
A last alternative is spraying chemicals on your plants. That being said there really aren’t any sure fire chemicals that seem to work well on the white flies. Some insecticidal soaps or oils are said to be somewhat effective but they are very hard to apply and invariably need reapplication.
One of the most effective methods of control is to spray water on the pests regularly. Researchers swear by the method. They say a strong stream of water directed weekly at the underside of the infected plant leaves will do the trick. As it works you can cut back your spraying to every two or three weeks.
A 10-pound bag of worm castings can usually be found in your nursery and it is typically used for plant beds and plant nutrients. Clear away debris from the base of my hibiscus and trench around the plant to a depth of about six inches. Fill the trough with the worm castings, fill the trench with water and lightly cover the area with soil. The key is reapplication every few months.