Citrus mealybug

Scientific name

Planococcus citri (Hemiptera: Pseudococcidae)

Similar species

passionvine mealybug, Planococcus minor

Field specimens of citrus mealybug cannot be distinguished from passionvine mealybug. Confirmation requires slide-mounting and/or molecular testing of the adult female.

Distribution

United States: Alabama, Arkansas, Florida, Georgia, Kentucky, Louisiana, Missouri, North Carolina, and Puerto Rico.

Worldwide: Cosmopolitan, most citrus growing regions.

Diagnostic characteristics

Adult females

• 3.0 mm (0.12 in.) in length and 1.5 mm (0.06 in.) in width.
• Pink body when newly molted, transitioning to orange-brown when mature. Brown-red legs.
• Wax does not obscure body color, but insect appears "dusted in flour."
• Oval.
• Wingless.
• Antennae have eight segments.
• A single line on top of the insect extends from 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
  to anus and appears to bisect the body into symmetrical halves.
• A horizontal ring of short and curved wax filaments extend outward from the body edge (margin) and the posteriorposterior:
  orientation pertaining to the rear of the body
  end, encircling the insect. Differs from many other mealybugs in that the posteriorposterior:
  orientation pertaining to the rear of the body
  filaments are approximately the same size as the ones from the margin. In many other species, the filaments are longer in the posteriorposterior:
  orientation pertaining to the rear of the body
  than the margins.
• Filaments are short and triangular with approximately 17 - 18 filaments on each side.
• The ovisacovisac:
  structure attached to the body that contains eggs; produced by many scale insects
  is under the body of the female and resembles a tuft of cotton with eggs interspersed.

Adult males

• Males are smaller and narrower than the females, but appear to be 4.5 millimeters long due to the wings and tail filaments.
• Reddish-brown.
• Elongate and narrower initially; resembles a two-winged gnat when mature.
• Two wings with minimal venation.
• Antennae appear "hairy."

Immature females

• Four instars.
• First instarinstar:
  immature stages (larva or nymph) of insects in between molts
  mobile crawlers are yellow with red eyes and distinct antennae.
• Nymphs resemble larger adult females.
• Antennae have six segments for instars one and two, then seven segments until adulthood.

Immature males

• Three instars as a nymphnymph:
  the immature or juvenile stages of insects that do not undergo complete metamorphosis; look similar to the adult and develop to the adult stage through a series of incremental changes that does not include a pupal stage
  , followed by a pre-pupapre-pupa:
  the non-feeding last instar larva of insects that undergo complete metamorphosis
  and pupa.
• First instarinstar:
  immature stages (larva or nymph) of insects in between molts
  mobile crawlers are yellow with red eyes.
• Resemble the female for the first three instars, followed by pupa that produces a cottony-appearing cocooncocoon:
  the protective covering around the pupa of some insects
  .

Eggs

• Yellow to amber.
• Oblong.
• 400 - 600 eggs are laid in a fluffy and cottony-appearing white ovisacovisac:
  structure attached to the body that contains eggs; produced by many scale insects
  .

Hosts

Citrus hosts

• citron, Citrus medica
• common mandarins (including tangerine), Citrus reticulata
• grapefruit, Citrus paradisi
• lemon, Citrus limon
• pummelo, Citrus maxima
• sour orange, Citrus aurantium
• sweet orange, Citrus sinensis

Non-citrus hosts

It is a common pest of ornamental plants, and infests at least 27 plant families. It is also a common greenhouse pest. Highly polyphagous and can be found on many flowering plants including:

• Annona spp.
• banana, Musa spp.
• carambola, Averrhoa carambola
• Coffee, Coffea arabica and C. robusta
• flowering ginger, Heliconia spp.
• geranium, Pelargonium spp.
• ginger, Zingiber officinale
• guava, Psidium spp.
• longan, Dimocarpus longan
• lychee, Lychee chinensis
• Macadamia spp.
• mango, Mangifera indica
• orchids, multiple genera
• persimmon, Diospyros spp.
• sago palm, Cycas revoluta
• Theobroma cacao

Host damage

Fruits

• Feeding damages the fruit rind.
• 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 fruits and leaves and promotes the growth of sooty mold fungus that inhibits photosynthesis, weakens the plant, and makes fruit unattractive.

Leaves

• Yellowed, chlorotic, and potentially distorted leaves.

Roots

• Infested roots cause leaves to wilt and turn yellow.
• Roots attacked by mealybugs can become encrusted with a greenish-white Polysporus fungus that can kill the tree.

Twigs

• Heavy feeding on twigs can cause premature leaf, fruit, and flower drop.

Biology

Eggs are produced sexually or asexually (parthenogenesis). Males are rare, typically fly in the early morning, and live only a few hours. The citrus mealybug overwinters as an egg on the upper roots, trunk, and lower branches of a tree. Mealybugs remain mobilemobile:
able to move
during their entire lifespan and have been shown to disseminate occasionally by wind and hitchhike on other creatures. Citrus mealybugs prefer humid and shaded conditions and are often tended by ants.

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

Ben-Dov, Y. 2001. ScaleNet, Planococcus citri. (http://www.sel.barc.usda.gov/scalekeys/Mealybugs/Key/Mealybugs/Media/html/Species/Planococcus_citri/Planococcus_citri.html).

Gullan, P.J. 2000. Identification of the immature instars of mealybugs (Hemiptera: Pseudococcidae) found on citrus in Australia. Aust. J. of Entomology 39: 160-166.

Kerns, D., G. Wright, and J. Loghry. 2002. Citrus arthropod pest management in Arizona. (http://www.azda.gov/CDP/NewCBC/ACRC/ACRC2002Research/2002-05.pdf).

Martin, J.L., and R.F.L. Mau. 2007. The crop knowledge master: Planococcus citri (Rizzo).(http://www.extento.hawaii.edu/Kbase/crop/Type/p_citri.htm).

Miller, D.R. 2005. Selected scale insect groups (Hempitera: Coccoidea) in the southern region of the United States. Fla. Entomol. 88: 482-501. (http://www.fcla.edu/FlaEnt/fe88p482.pdf).

Osborne, L. S. 2000. Mealybugs. (http://mrec.ifas.ufl.edu/lso/Mealybugs.htm).

Polat, F., S. Ulgenturk, and M.B. Kaydan. 2007. Developmental biology of citrus mealybug, Planococcus citri (Risso) (Hemiptera: Pseudococcidae), on ornamental plants, pp. 177-184. In M. Branco, J.C. Franco, and C. Hodgson (eds.), Proceedings, Symposium: XI International Symposium on Scale Insect Studies, 24-27 September 2007, Oeiras, Portugal. ISA Press, Lisbon, Portugal.

Von Ellenrieder, N. 2003. California Department of Agriculture fact sheet: citrus mealybug (Planococcus citri: Pseudococcidae). (http://www.cdfa.ca.gov/phpps/PPD/PDF/planoccus_citri.pdf).

Authors

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