Whiteflies are small insects that often present a problem for gardens. These pests suck sap out of plants and excrete honeydew while doing so; some types of whiteflies even transmit viruses to the plants. The loss of sap weakens plants, causing leaves to yellow or even die. In addition, the excretion of honeydew invites mold, interfering with a plant’s ability to photosynthesize.
Adult whiteflies generally look like moths with yellow bodies covered in a white, waxy powder. They are small, between 1/10 inches to 1/16 inches (about 0.25 cm to 0.16 cm) in length. Normally, these pests reside on the underside of leaves, which is also where females lay their eggs. After the eggs hatch, the nymphs go through four immature stages in which they suck sap from plants and excrete honeydew.
Generally, adults are not as harmful as nymphs. Large infestations of nymphs can be detrimental to the life of plants. There are many types of whiteflies that might be found in a garden. Some of these are the bandedwinged whitefly, the greenhouse whitefly and the sweet potato whitefly. Different whiteflies reside on a range of different host plants.
Dealing with these pests can be a difficult task. It is best to try and eliminate them at the start of an infestation because a single female can lay about 200 to 400 eggs. In addition, adults can be hard to target because of their ability to fly. To get rid of eggs and nymphs, a good start is for gardeners to take infected leaves off of plants. To kill adults, individuals can vacuum the leaves and freeze the insects in a plastic bag overnight.
Another way to get rid of adult forms of the pest is to make traps. The traps are made of materials such as cardboard or plywood. They are painted yellow and coated with a sticky substance such as petroleum jelly. Adults fly to the trap because of the color and they get stuck on the substance. Traps are only efficient if there are a sufficient number of them compared to the number of plants.
In addition, a good way to control these pests is to invite or introduce their natural enemies into the garden. Natural predators of whiteflies include lacewings, lady beetles and minute pirate bugs. Two ways to get these predators are to buy them or to plant something that will attract them.
Insecticides might work in reducing the number of these pests, but there are drawbacks. One drawback is that it might eliminate the insect’s natural enemies. Another is that most insecticides need to come into contact with whiteflies in order to kill them. If an insecticide is used, it should be targeted towards the underside of the leaves where the pests reside.
Whiteflies will travel from one plant to another. If an infested plant is introduced to a garden, it should be kept away from other plants until it has been treated. In addition, it is a good idea to immediately dispose of an infested plant that has been removed from the garden. This is so the pests do not get a chance to move onto nearby plants.