Every year it is a guessing game as to which invading pest will be the first to arrive in my yard. Some years it is Aphids, others Mealybugs....This year it's Whitefly.
There seems to be many more than I have ever seen before. They are all over the Citrus, Tomatoes, Potatoes and Peppers. I have the typical white cloud of fluttering insects when I water.
Whiteflies are not true flies as they are relatives of mealybugs, scales and aphids. All of these insects suck the life right out of your plant, literally. They are piercing insects that suck the juice from the plants tissue. They attack the leaves, buds and stems.
Adult Whiteflies are about 1/10 to 1/16 inch long and look like tiny moths.
Adult females usually lay between 200 and 400 eggs. Sometimes the eggs are deposited in a circular pattern in groups of 30 to 40 because the female will often keep her mouthparts in the plant to feed while moving her abdomen in a circle. How is THAT for lazy?!
Within about a week, the eggs hatch into flattened nymphs, called crawlers, that wander about the plant. Very soon after that, the crawlers insert their mouthparts and begin to feed. If your infestation is bad enough, you can literally have all generations present at the same time. Adults to eggs and all points in between.
It is the nymph and adult fly that cause the physical damage to the host plants. The plants can be seriously weakened and grow poorly, becoming stunted. Leaves often turn yellow, appear dry and drop prematurely, ultimately the plant can die. If this isn't bad enough, Whiteflies produce honeydew (like aphids) that can drip onto the plant encouraging the growth of sooty mold. They also can spread plant viruses. I am really NOT a fan of Whitefly.
The Silverleaf Whitefly has over 500 host plants, this is the one that has come to visit me. Many other Whitefly are more plant specific. Luckily, there are a number of natural predators. The Ladybug larvae will consume up to 1000 Whitefly eggs in its lifetime, and they also feeds on the nymphs. Green Lacewing, which is probably the most voracious, effective predator, eats them. Online, you can order the Delphastus beetle, a specific predator of Whiteflies. It has to eat them in order to reproduce. Other natural enemies are Minute Pirate Bugs, Big Eyed Bugs, and Damsel Bugs. There are also many songbirds, including swallows, that feed on Whitefly.
Some things that you can do to help your natural predators include: Use a seaweed spray to mist the leaves of your plants. Along with all the benefits plants derive from a seaweed spray it also seems to make the foliage undesirable for Whiteflies to reproduce on. Insecticidal soap is another alternative. White flies being soft-bodied insects can be successfully controlled and prevented with insect soap sprays. It basically dries them out. You can plant Marigolds around your prize plants, this may help some. I have not had much luck myself with this method, they still seem to show up. A light horticultural oil will work.There is one other safe control to try, this one really tickled me when I read about it. Use a vacuum to carefully suck up as many Whiteflies as you can. Dustbuster units are ideal for this. As a last resort, you can use Pyrethrum or Malathion sprays. The key to using these products is to directly spray the pests. Their location on the underside of the leaf makes it difficult to deliver insecticides to the site where they are found. Also, Whiteflies can rapidly develop resistance to the insecticides used against them. Always read and follow the label directions carefully.
Hopefully, you won't have to deal with this menace. At least if you do, you know how to handle them now. As for me, I am going to give Mother Nature a couple of days to take care of my little problem. If she fails, I have no problem bringing out the big guns.....Now what was the code for that nuke!?