Citrus Mealybugs
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DESCRIPTION
Adult- The female citrus mealybug is wingless and appears to have been rolled
in flour (hence the name). It grows to 3 mm long and 1.5 mm wide. A
fringe of small waxy filaments protrude from the periphery. The male is small,
but with its wings and tail filaments, it appears to be 4.5 mm long.
Egg- The oblong, yellow eggs are enmeshed in a dense, fluffy, white ovisac.
Crawler- The tiny crawler is oval and yellow, with red eyes. The antennae are rather distinct.
Nymph- Female nymphs resemble the larger adult females. Male
nymphs are narrower and often occur in a loose cocoon.
Fig. 106: Citrus mealybug
Planococcus citri (Risso), Pseudococcidae, HOMOPTERA
Zoom Fig. 106: Full view of life cycle (25.4 K)
Citrus mealybug. A, Adult female. B, Egg mass. C-G, Nymphs. H, Adult male.
BIOLOGY
Distribution- Citrus mealybugs occur m southern Europe and in the
southern United States, where they overwinter outdoors. Further north, they survive in
greenhouses and homes.
Host Plants- Citrus mealybugs have been collected from at least 27 host plant
families. Many ornamental plants grown in greenhouses are susceptible to
attack including begonia, coleus, amaryllis, cyclamen, and dahlia. Citrus
mealybug has been collected on canna, narcissus, and tulip outdoors.
Damage- Vitrus mealybugs damage hosts by sucking out plant sap, by
excreting honeydew in which sooty mold can grow, and by causing
distorted growth and premature leaf drop with their toxic saliva. They
further disfigure plants by secreting cottony wax. Infested plants usually
die unless the pest is controlled.
Life History- The citrus mealybug has been recognized as a pest of citrus
and ornamental plants in Europe since 1813 (where it is called the
greenhouse mealybug) and in the United States since 1879. Because
female citrus mealybugs have no wings, they must be transported to the
proximity of the next host plant. They can, however, travel short distances
by crawling and the immatures can be blown about. Males are small, winged
insects. After mating, each female lays up to hundreds of eggs in a dense,
fluffy secretion called the egg sac or ovisac. Within a few days, new mealybugs
(crawlers) hatch and begin to squirm out of the ovisac. Light infestations are
easily overlooked because the mealybugs tend to wedge into crevices on the
host plant. As their numbers increase, mealybugs of all sizes can be seen
crawling around or feeding on all exposed plant surfaces.
CONTROL
Control of citrus mealybugs is amazingly difficult. Some commercial flower
growers merely discard infested plants rather than trying to rescue them from
citrus mealybugs. Horticultural oils may damage amaryllis. For specific chemical
controls, consult the current Cooperative Extension publications on ornamental plant pest
management or consult your county Extension Agent.
Zoom Fig. 106: Full view of life cycle (25.4 K)