Root Mealybugs

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DESCRIPTION

Adult Female-
The ground mealybug is white and 2.4 to 3.9 mm long. It resembles a springtail, but moves much more slowly and cannot jump. The ground mealybug has slender waxy filaments that form a sort of netting over some individuals. The ground mealybug also secretes a small amount of wax, which can give the soil a somewhat bluish appearance when the mealybugs are abundant. Pritchard's mealybug is snow white and 1.6 to 2.1 mm long and oval. It has small- to non-existent eyes.

Click on Image for full view which includes Fig. 109: Root mealybugs (ground mealybug), Rhizoecus falcifer Kunckel d'Herculais; Pritchard's mealybug, Rhizoecus pritchardi McKenzie; and Rhizoecus americanus (Hambleton). Pseudococcidae. HOMOPTERA

Fig. 109 (full view) A, E, N, P: Mealybugs on root of African violet. A, Adults, E, Eggs. N, Nymph. P, Particle of Perlite.

BIOLOGY

Distribution-
The ground mealybug was described in France and occurs in scattered locations across the United States. Pritchard's mealybug is found across the United States.

Host Plants-
The ground mealybug feeds on the roots of anemone, chrysanthemum, gladiolus, iris, and numerous other flowers, shrubs, and ornamental grasses. Pritchard's mealybug has become a serious pest of African violet, although it also infests Achillea, Arctostaphylos, Geum, and Polygala.

Damage-
At times the ground mealybug becomes abundant enough to damage its host. Pritchard's mealybug causes devitalization, foliage deterioration, and even death of its host plant.

Life History-
Little has been published on the life history of root mealybugs. When infested African violets are irrigated, Pritchard's mealybugs crawl out of the drainage holes and spread throughout the greenhouse. Eggs are laid in a loose ovisac in clusters of at least six eggs. All stages can be found on the roots and potting mix of African violets where they resemble slow moving, snowy white collembola.

CONTROL

Pesticides applied as dips, drenches, or granulars are more effective for root mealybug control than are foliar sprays. For specific chemical control recommendations, see the current Cooperative Extension publications on ornamental plant pest management or consult your county Extension agent.