Soil Mealy Bugs

Sometimes called "Blind Mealy Bugs," Pritchard Mealy Bugs (Rhizoecus dianthi, formerly Rhizoecus pritchard) or Root Mealy Bugs (Rhizoecus americanus)

Description

Soil Mealy Bugs are insects that measure about 1/16 inch. Because they are white or light gray in color, they often resemble small grains of rice. Soil Mealy Bugs feed on the roots of African Violets, particularly the new feeder roots in the upper layer of the soil. The resulting damage stifles the ability of roots to absorb water and nutrients.

Distinguishing Symptoms

• Visible insects. Soil Mealy Bugs are tiny white or gray insects, resembling small grains of rice, are visible on the surface of the rootball. You may also see these insects on top of the soil, gathered around the main stem. If this is the case, infestation is probably heavy. (Do not confuse Soil Mealy Bugs with Symphylans. Both are small insects which may be found on the rootball of African Violets. However, whereas Soil Mealy Bugs look like tiny grains of rice, Symphylans look like tiny centipedes.)

If your African Violet has this symptom, it probably has Soil Mealy Bugs.

Other Symptoms

• Leaves pale. They appear yellow or grayish in color.
• Leaves wilt. They may appear translucent brown with a soft, jelly-like consistency.
• Not flowering.
• Plant growth is slow.

Treatment

First, isolate the affected plants, especially if they share a common watering tray with other, healthy plants. Although Soil Mealy Bugs do not spread easily, they will travel over moist surfaces.

Traditionally, the only effective treatment for Soil Mealy Bugs has been to spray the soil with Acephate (as directed on the label) or with Malathion (1 teaspoon of Malathion 50 per 4 liters of lukewarm water). While this treatment does work, it usually takes several applications over a period of days. Moreover, there is usually some risk to plants when using any chemical treatment.

A promising alternative to chemical treatments has been found in the use of Diatomaceous Earth, a fully inert, non-volatile substance that has proven effective in eradicating certain insect pests. Strictly speaking, Diatomaceous Earth is not an insecticide. It is made from the skeletal remains of diatoms, a microscopic form of algae. When processed into Diatomaceous Earth, these skeletal remains form razor-sharp particles which cut into the bodies of small insects. While eradicating the insects, Diatomaceous Earth does not harm African Violets.

To treat for Soil Mealy Bugs, you will have to repot your African Violet in a soil that has been mixed with Diatomaceous Earth. Use about 1 tablespoon per one liter of soil.

Prevention

Pasteurize soil before repotting. To make soil uninhabitable for future Mealy Bug infestations, mix about 1/4 tablespoon of Diatomaceous Earth with every liter of soil.

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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