Broad Mites

(Polyphagotarsonemus latus)

Also known as Tropical Mites and Yellow Tea Mites

Description

Broad Mites are tiny arachnids and, as such, have eight legs. They may be white, yellow or brown in color. Because they measure only 1/150 inch, they can only be seen with a magnifying glass. Broad Mites feed on the underside of the leaves. The damage caused by Broad Mites is compounded by the fact that some mites are carriers of Botrytis. Since Broad Mites will quickly move from plant to plant, it is important to detect them early.

Distinguishing Symptoms

• Visible insects or other pests. Broad Mites are arachnids and, as such, have eight legs. They are white, yellow or brown in color and measure about 1/150 inch. Because of their tiny size, you will probably need a magnifying glass to see them. When present, they will be found predominantly on the underside of the leaves, especially along the veins. This said, do not let yourself get caught up in making a definitive identification. It is enough to know they are mites, since the treatment for all mites is the same. (See below.)

If your African Violet has this symptom, it probably has Broad Mites.

Other Symptoms

• Leaves pale. They appear yellow in color.
• Leaves darken on the edge. Edges appear brown in color (necrosis). The feeding activity of mites tends to turn leaves yellow with a dark edge.
• Leaves have dark speckles on the underside of them. The dark speckles left by Broad Mites will be found predominantly on the underside of the leaves, especially along the veins. These speckles are actually small scars caused by the feeding activity of the mites.
• Leaves are deformed or twisted.
• Leaves curl down on the edge.
• Leaves have yellow spots on them.
• Leaves have streaks on the underside of them. These streaks may give the entire underside of the leaves a silvery appearance.
• Leaves are brittle or cracked.
• Plant growth is slow.

Treatment

First, isolate all infested plants. This is important, since Broad Mites move quickly from plant to plant.

Next, treat with Dicofol (as directed on the label). You will need to spray three times, once every fourth day after the initial treatment. Be sure that the spray reaches the underside of the leaves, since this is where most Broad Mites tend to concentrate.

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 Broad Mites by making the plant unpalatable. 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 Broad Mites tend to cluster.

Prevention

Always isolate new plants until you can positively determine that they are not infested.

Thoroughly wash hands before handling your plants.

Before repotting, pasteurize soil and disinfect pots with a 10 percent bleach solution, i.e., 1 part bleach to 9 parts water.

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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