Whiteflies

Description

Whiteflies are small, flying insects which measure 1/16 to 1/8 inch in length. As their name suggests, they are white in color. Whiteflies feed on the juices of African Violets, particularly on the undersides of the leaves.

Distinguishing Symptoms

• Leaves have honeydew on them. Honeydew is a shiny, sticky substance left behind by certain insects. Honeydew will often host a thin, black fungus called Sooty Mold. Other insects which leave behind honeydew include Aphids, Leaf Mealy Bugs and Scale. These insects, however, are easily distinguished by their physical characteristics. (Note: Do not mistake the honeydew left by Whiteflies and other insects with the mucus trail left by Snails and Slugs.)
• Visible insects. Look for tiny, white insects which fly up in a cloud whenever the leaves are disturbed. When undisturbed, Whiteflies will normally cluster on the undersides of the leaves.

If your African Violet has these symptoms, it probably has Whiteflies.

Other Symptoms

• Leaves have a black fungus on them. This is probably Sooty Mold, which finds a host in the honeydew left by Whiteflies and other insects. When Sooty Mold is present, the upperside of the leaves will be covered with tiny, dark speckles.
• Leaves pale. They appear yellow or grayish in color.
• Plant growth is slow.

Treatment

Spray with Acephate every two to three days until no more Whiteflies are present. When spraying, it is crucial to treat the undersides of the leaves where Whiteflies tend to cluster. Be sure to spray all of your Violets, not just those where symptoms have been spotted. Whiteflies spread quickly, so if even one Violet has them, all are at risk.

Acephate is available in a number of all-purpose, household insect sprays. Acephate sprays of this type, however, may damage foliage due to a specific additive which these sprays contain. As an effective alternative, use a soluble powder, and mix your own spray.

As an alternative to traditional chemical treatments, try spraying with Neem (Azadirachtin). Neem is a substance which has natural insecticidal properties, and according to currently available research, it is biodegradable and non-toxic. When sprayed on African Violets, it discourages Whiteflies by making the plant unpalatable. Those Whiteflies which do continue to feed on the Violet will be rendered incapable of laying eggs. Though Neem does have some systemic effect in plants, spray it as you would other contact insecticides, being sure to cover the undersides of the leaves where Whiteflies tend to cluster.

Another alternative to traditional chemical treatments is to trap the insects. This can be done by taking a narrow strip of wood, painting it with a bright color and coating it with something sticky. Your wood should be about 12 to 18 inches long and 1 to 3 inches wide. Paint it orange or deep yellow, then apply a generous coating of honey or molasses. According to those who use this method, the bright color attracts the insects. Once they land on the strip, the honey or molasses holds them there. To be effective, the strip must be placed among your Violets so that it is in close proximity to wherever the insects are flying.

Prevention

There is no sure way to prevent Whiteflies. You can, however, prevent heavy, more costly infestations by simply keeping a watchful eye for the first indications that Whiteflies are present.

Important Note on the Use of Pesticides

Please note that almost all pesticides are formulated for specific uses and conditions. When applied incorrectly, pesticides can cause ill health or damage to plants. Therefore, when using any kind of pesticide or chemical treatment, always apply as indicated on the product label.

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