AZALEA MEALYBUG (Eriococcus azaleae).
The correct name is bark scale,
but it looks like a mealybug with its white cottony masses at axils
of twigs and branches and has long been called that. This is a common
and injurious enemy of outdoor azaleas through the South, devitalizing
them and turning them black with quantities of sooty mold growing in
the honeydew. In Alabama nymphs of the first generation hatch in April,
those of the second in September.
Control. Two sprays of Volck or other summer oil (3 tablespoons
Florida Volck or 41/2 tablespoons Nursery Volck, plus 2 tablespoons
powdered derris and 1 teaspoon nicotine sulfate per gallon of water) have
given reasonably good control. The first spray is applied in May, the
second at the end of September. Commercial growers have been using
parathion in recent years.
CITROPHILUS MEALYBUG (Pseudococcus gahani).
This long-tailed mealybug, with posterior filaments a third the length of the body, is
common on citrus and many ornamental plants. It thrives in the cool
coastal areas of California but can be kept under control by parasites
imported from Australia.
CITRUS MEALYBUG (Pseudococcus citrt).
A short-tailed form, very common
in greenhouses and on house plants-on African violet, coleus,
begonia, fuchsia, cactus, poinsettia, and a long list of other ornamentals.
The white powder is very dense, and the copious secretion of honeydew
attracts ants which help to disseminate the mealybugs.
Control. It sometimes helps to syringe plants with water; house plants
should have a weekly bath. Control ants by drenching nests with chlordane (3 tablespoons of 50% wettable powder to a gallon of water). Pick
off occasional mealybugs by touching with a swab dipped in alcohol. For
stubborn cases spray with summer oil (such as Volck at a 1 to 50 dilution), but keep plants in shade during and after treatment and rinse off
with water after a few hours. Use phosphate bombs in greenhouses.
COMSTOCK MEALYBUG (Pseudococcus comstocki),
catalpa mealybug. This
is another long-tailed mealybug, fairly widely distributed in temperate climates, a special enemy of apple and umbrella catalpa, some-
times found on other trees. When clustered on apple twigs, the mealybugs resemble a mass of woolly aphids. On both apple and catalpa the
bugs congregate around pruning scars and crevices and at limb crotches.
Control. Scrub the bark with a brush and soap and water. Spraying
with DDT seems helpful for this particular mealybug, while parathion
is apt to kill its parasites.
GRAPE MEALYBUG (Pseudococcus maritimus).
This is an omnivorous underground feeder in California where it injures grapes, pears, citrus,
and English walnut as well as many ornamentals. In Florida it is found
on avocado and tomato and appears in the North on stored gladiolus