Comstock mealybug

Scientific name

Pseudococcus comstocki (Hemiptera: Pseudococcidae)

Other common names

Japanese mealybug

Similar species

Pseudococcus apodemus

citrus mealybug, Planococcus citri
The Comstock mealybug can be distinguished by a thicker wax cover than the more common citrus mealybug.

grape mealybug, Pseudococcus maritimus

Odermatt mealybug, Pseudococcus odermatti

Distribution

United States: California, Connecticut, Delaware, Georgia, Illinois, Indiana, Louisiana, Maryland, Massachusetts, Michigan, New Hampshire, New Jersey, New York, Ohio, Pennsylvania, South Carolina, Virginia, and West Virginia.

Worldwide: Asia, Central and South America, Europe, and North America.

Native to Japan.

Diagnostic characteristics

Adult females

• 2.5 mm (0.1 in.) to 5 mm (0.20 in.) length.
• Pink to reddish-brown visible only between the body segments, the rest of the insect is covered in mealy white wax.
• No line between the headhead:
  one of the three main body segments in insects; the anterior-most segment containing the many sensory structures including the eyes, antennae, and mouthparts
  and tail is visible on the top of the insect.
• Elongate, oval with well-developed legs.
• Wingless.
• 17 straight and thin wax filaments on the sides; two pairs of filaments at the rear (posterior) of the insect are the longest at 1/4 to 2/3 body length.
• The ovisacovisac:
  structure attached to the body that contains eggs; produced by many scale insects
  contains and protects newly-laid eggs and is kept underneath the body.

Adult males

• Less than 1 mm (less than 0.1 in.) in length.
• Reddish-brown. < LI>Gnat-like with two long tail-like filaments as long or longer than the entire body.
• Delicate wings, appearing almost veinless.
• Antennae with ten segments.
• Three pairs of eyes and no mouthparts.

Immature females

• Three nymphal instars.
• 0.3 mm (less than 0.1 in.) to 2.5 mm (0.1 in.) in length.
• Salmon color initially, darkening to light brown with age.
• Oval and flattened.

Immature males

• Five nymphal instars.
• Approximately 3 mm (0.12 in.) long.
• Orange-yellowish with less wax covering.
• First instarinstar:
  immature stages (larva or nymph) of insects in between molts
  is a small and oval crawling stage.
• Third instarinstar:
  immature stages (larva or nymph) of insects in between molts
  called "pre-pupapre-pupa:
  the non-feeding last instar larva of insects that undergo complete metamorphosis
  " and spins silken coccon.
• Later instars contained within coccoon.

Eggs

• 0.3 mm (less than 0.1 in.) long and 0.17 mm (less than 0.1 in.) wide.
• Ranges from bright orange-yellow to pinkish brown.
• Eggs are laid in masses under bark crevices or fruit calyxes.

Hosts

Citrus hosts

• lemon, Citrus limon

Non-citrus hosts

Primarily infests deciduous fruit trees and ornamentals.

• banana, Musa spp.
• boxwood, Buxus sempervirens
• Fatsia spp.
• jasmine, Jasmium officinale
• mulberry, Morus spp.
• peach, Prunus persica
• pear, Pyrus communis
• pomegranate, Punica granatum
• privet, Ligustrum spp.
• umbrella catalpa, Catalpa spp.

Host damage

Fruits

• Infestation can cause reduced yield and lowered fruit quality.
• May retard or delay ripening.
• Honeydew honeydew:
  the sugar-rich waste product excreted by aphids, mealybugs, and scales insects as a result of feeding on the phloem of plants
  excreted by mealybugs coats the outside of fruit and promotes the growth of sooty mold fungus that inhibits photosynthesis, weakens the plant, and makes fruit unattractive.

Leaves

• Lowered growth and vitality.

Biology

Eggs are oviposited under bark crevices, pruning cuts, or other protected areas. In the spring, eggs hatch into mobilemobile:
able to move
first instarinstar:
immature stages (larva or nymph) of insects in between molts
nymphs, known as crawlers. Crawlers seek out leaves and shoots to feed upon until they mature in the late summer. The adults lay eggs, and a second generationgeneration:
the time it takes for an insect to develop from egg to adult
hatches in approximately 11 days. The young females mature by late fall and lay eggs capable of overwintering in some temperate areas. Occasionally, the nymphs and adults are able to overwinter.

Comments

All phloem-feeding, honeydew-producing pests have the potential to be tended by ants. The ants feed on the honeydewhoneydew:
the sugar-rich waste product excreted by aphids, mealybugs, and scales insects as a result of feeding on the phloem of plants
excreted by the pest and protect the pest from natural enemies. This protection can disrupt biological control programs.

References

Borkhseniusa, N.S. 1948. Notes on Pseudococcus comstocki (Kuw.) and some allied species (Homoptera: Coccoidea), with descriptions of three new species. Bull. Entomol. Res. 39: 417-421. Cambridge University Press, Cambridge England.

Gill, F.J. (ed.). 1999. California plant pest & disease report. California Department of Food and Agriculture - Plant Pest Diagnostics Center. pp. 76-77. (http://www.cdfa.ca.gov/phpps/ppd/PDF/CPPDR_1999_18_5-6.pdf).

Grafton-Cardwell, E.E. 2008. How to manage pests: U.C. pest management guidelines: Citrus - citrus mealybugs, citrus mealybug: Planococcus citri. U.C. IPM Pest Management Guidelines: Citrus U.C. A.N.R. Pub. 3441. (http://www.ipm.ucdavis.edu/PMG/r107300511.html).

Miller, D.R., A. Rung, G.L. Venable, and R.J. Gill. 2007. Scale Insects: Identification tools for species of quarantine significance. CBIT Publishing, Queensland, Australia. (http://www.sel.barc.usda.gov/ScaleKeys/ScaleInsectsHome/ScaleInsectsHome.html).

Reuther, W., E.C. Calavan, and G.E. Carman (eds.). 1978. The citrus industry: Crop protection. Univ. of California, Div. Agric. Nat. Resources.

Spangler, S.M., and A. Agnello. 1991. Comstock mealybug insect identification sheet. (http://www.nysipm.cornell.edu/factsheets/treefruit/pests/cmb/cmb.asp).

Walgenbach, J., A. S. Napier, and S. Schoof. 2007. Southeastern apple production entomology fact sheet: Comstock Mealybug Pseudococcus comstocki (Kuwana).(http://www.ces.ncsu.edu/fletcher/programs/apple/entomology/insects-mites/CMBfact.html).

Authors

Martin, K.W., A.C. Hodges, and N.C. Leppla