Common pests (Mites, mealy bugs, thrips)
MITES: Mites are the most dreaded of the African violet pests because of the damage they cause and the difficulty (and expense) of eradicating them. Mites are tiny arachnids, measuring about 1/100 of an inch. Most people need a jeweler's loupe to see them. The damage is usually in the center, or crown, of the plant. You may notice the crown is deformed, hairy or tight. Mites produce a toxin that causes the leaves to curl, twist and become stunted. Too much light or too much fertilizer can also cause similar symptoms. To kill the mites, you must treat the plants with a miticide such as Avid, Pylon or Kelthane (Dicofol). Cape Cod Violetry and Grower Supply sell these products. Other treatments such as Neem oil may control mites but will not kill them. Some growers choose to throw out plants with mites rather than to treat because of the difficulty and expense involved.
MEALY BUGS: These white insects are visible to the naked eye and are about 1/8 to 1/16 of an inch. They may look like specks of cotton on the leaves or leaf axils. Mealy bugs may also be found in the soil, where they will look like grains of rice. The symptoms are generally a plant that fails to bloom, grow and is just suffering overall. Treat with Malathion or Marathon. Marathon is available from Cape Cod Violetry or Grower Supply. Other treatments such as dipping a cotton swab in alcohol will control the problem, but not rid the plant of the insects.
THRIPS: These insects are about 1/50 of an inch. You can see them with the naked eye, although a jeweler's loupe may help. Thrips are most often found in the flowers. Gently blowing on the blossom may make them more visible. A classic symptom is yellow pollen spilled on the flowers. The first step in eradicating thrips is to disbud the plant. This means removing all flowers and flower stalks. It deprives the thrips of their favorite food. After disbudding, treat with Neem Oil, Malathion, Marathon, Avid or Conserve. Keep disbudding for at least six weeks.
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