A 'cloud' of these critters can be seen when infected plants are disturbed. You can easily identify these insects by the white and waxy substance secreted by their abdominal glands.
A female whitefly lays around 200 - 300 eggs in a lifetime. It takes three weeks for the species to grow into an adult. At this rate of reproduction, a mammoth effort is required on your part to get rid of them. If you are to tackle whitefly infestation, you will have to regularly spray contact or organic chemical pesticides on whitefly-infested plants.
Symptoms of Whitefly on a Plant
If you have a few plants, then it is easy to check their leaves, but if you have a variety of plants, then checking each and every plant would be impossible, and you will have to rely on the symptoms of infestation.
Home Remedies to Control Them
Depending on the intensity of infestation, you should decide whether you want to treat the plant with an insecticide or resort to natural remedy. If you want, you can use a natural insecticide. However, if you have pets, then use of insecticides can be risky. Check whether your plant is included on the label of the insecticide.
A spray containing acephate or malathion works great for whiteflies. You are supposed to coat both sides of the affected leaves. Do not forget to cover your eyes and keep the area properly ventilated. If you are looking for natural remedies, then here's a simple recipe.
Blend all the ingredients, add a little water, and keep it overnight. Next day, sieve it and add some water. Your homemade pesticide is ready! Ideally, you can spray it once in a week. In case of heavy infestation though, you might have to use it twice or thrice a week.
Another simple home remedy that works great for whiteflies involves the removal of infested leaves. Remember, you are expected to remove the leaves with eggs too.
You can then apply a thick coat of some sticky substance, such as petroleum jelly, on a bright-colored―preferably yellow or orange―cardboard box and keep it near the tree. These insects get attracted to bright colors, so they are bound to run into the cardboard and get stuck to it.
Covering the unaffected plants with a layer of horticultural fleece can keep them free from whiteflies. Pesticides containing thiacloprid, thiamethoxam or acetamiprid are also helpful in getting rid of these insects.
Organic pesticides can protect plants from infestation for several weeks. You can also hang bright-yellow sticky traps above the plants in greenhouse to attract them.
Biological Pest Control
It's a natural way of controlling whiteflies, which involves using their enemies to kill them. The tiny wasp, Encarsia formosa that kills whiteflies is provided on commercial basis by some biological services.
Excessive use of pesticides has destroyed the natural enemies of whiteflies. It is also believed that certain insecticides are responsible for a marked increase in their capacity to reproduce. Limited use of pesticides or use of natural pesticides is therefore, necessary for maintaining the ecological balance.