How to Get Rid of Whiteflies

Control of whiteflies can be tricky, especially at the height of an infestation. These tiny insects have yellow bodies and white waxy wings. They hang out on the undersides of leaves and suck sap from plants, which causes leaves to turn yellow and fall off plants. Whiteflies produce sticky honeydew that causes a black mold to develop and impede photosynthesis. Whiteflies cause crop loss and devastate gardens, greenhouses or farms. The damage is costly, not just for growers either. Whiteflies carry viruses to other crops, in effect, spreading loss across the economy. Despite this, control of whitefly is possible with an integrated approach.

Whitefly Control

Where can I find pesticides for whiteflies? It's the first question gardener's ask at the onset of infestation. The truth is that pesticides do not always help with the control of whitefly. According to the United States Department of Agriculture Whitefly Knowledgebase, repeated applications make some whitefly strains resistant to pesticides. They also contain chemicals harmful to insects that you do not want to get rid of, such as bees that pollinate and natural whitefly predators.

Use insecticidal soaps or insecticidal oil sprays, if you must. Some products, such as Talstar One and Permethrin Pro, are geared toward nymphs and adults. Other products, like Safer Insecticidal Soap, are designed to eliminate whiteflies during the nymph and pupa stages. Either way, apply the insecticidal spray to the undersides of leaves before crops develop a dense canopy that prevents a thorough application. Spray plants weekly during peak population periods, but check the manufacturer's instructions as products may vary.

Whitefly Biological Control

Control whitefly with natural predators as a form of biological control. Gardeners prefer Lacewings and Lady beetles. Lacewings are shipped as eggs and hatch a few weeks later. They attack whiteflies, but there is always the chance the eggs may be eaten by ants and other predators before they hatch. Lady Beetles, also called Lady Bugs, are shipped live. They consume whitefly insect eggs - lots of them. The downside is that beetles do not stay in one location upon release. The upside is that they can live up to a year and reproduce continuously. Other natural enemies of whiteflies include Minute Pirate Bugs, Big Eye Bugs and Damsel Bugs.

Whitefly Traps

Traps are another option. Whitefly traps resemble large yellow sticky notes, but these yellow sticky pads have a grid printed on the front and are coated with a glue-like substance. The color yellow attracts whiteflies. When whiteflies land on the sticky pad, they become trapped. While traps will not kill whiteflies in total, they can reduce population when used with other methods.

Order traps for whiteflies online or make your own. Attach stakes to quarter inch plywood, pre-treated with yellow paint and commercial products like Strickem or Tanglewood. Set the stakes 3 to 5 feet apart at plant level, out of direct sunlight. The traps fill quickly and lose their effectiveness if they're not cleaned or changed monthly. The commercial products require a solvent for removal, so you may want make the sticky glue too, then wash the plywood pieces as they fill up. Mix petroleum jelly and detergent in a 1 to 1 ratio. Or, apply automotive oil to inverted yellow, plastic cups to create a gooey death grip.

Whitefly Mulch

Get rid of whiteflies with mulch, not the organic bark, but inorganic plastic. The protective layer looks like a trash bag when spread out, yet it improves plant growth, controls weeds, protects soil, repels whiteflies and reduces virus transmission in crops. Plastic mulch is available in a variety of colors at garden supply stores. Some colors deter insects better on certain plants. Silver seems to do the trick on whiteflies, so spray paint clear plastic mulch silver. To use plastic mulch in your garden, pull the weeds, layout the plastic and anchor the edges with soil. Cut holes that are 3 or 4 inches in diameter then plant or transplant as usual. Employ hose or drip irrigation and remove the mulch when it gets hot out to avoid overheating.

The best way to get rid of whiteflies is through prevention. Control ants and dust because they protect whiteflies from natural predators. Remove or transplant shade protected plants to a sunny, well ventilated location when possible. Also, contact your extension office to determine the type of whitefly invading your garden. A local expert may tell you which methods are better at controlling whiteflies in your area. The USDA suggests gardeners take an integrated approach to manage whiteflies. That means it's better to use a variety of biological controls, sprays, traps or mulches to get rid of whiteflies.

Source

USDA Whitefly Knowledgebase
http://entnemdept.ufl.edu/fasulo/whiteflies/wfly0002.htm