Citrus peelminer

Scientific name

Marmara gulosa (Lepidoptera: Gracillariidae)

Similar species

apple barkminer, Marmara elotella

apple fruitminer, Marmara pomonella

citrus leafminer, Phyllocnistis citrella
The serpentine leaf mines of the citrus peelminer can be distinguished from the citrus leafminer, because the peelminer does not leave an excrement (frass) trail within the mines like the citrus leafminer. Citrus peelminer mines are convoluted and often intersect. In contrast, citrus leafminer has compact mines that do not intersect.

Marmara salictella

Marmara fraxinixola

Marmara corticola

Marmara fulgidella

Distribution

United States: Arizona, California, Florida, and Texas.

Worldwide: Cuba and Mexico.

Native to the United States.

Diagnostic characteristics

Adults

• 4 mm (0.16 in.).
• Dark, silvery grey with mottled white and brown markings. Mostly cream to white on the underside (ventrally). Broad band of grayish-brown scales across the back of 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
  . White-banded legs and wings.
• Somewhat elongate and conical.
• Forewing forewing:
  the anterior (closest to the head) pair of wings in insects
  2.3 - 2.6 mm (0.09 - 0.1 in.) in length.
• No primitive eye spots (ocelli) on 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
  .

Pupae

• Orange to brown in color.
• Cocoon cocoon:
  the protective covering around the pupa of some insects
  is a firm sheet of white silksilk:
  a natural fiber produced by some insects that can be utilized to construct shelters, leave a trail, build a cocoon, etc.
  over a crevice in bark or on the ground in the leaf litter.
• Covered by 20 - 40 "frothy" balls.
• Balls are approximately 1 mm (0.04 in.) in diameter and have minute spines on the surface.

Larvae

• Five larval instars followed by a pseudo-pupa (spinning larva) and then a pupa prior to maturation.
• 4.4 mm (0.17 in.) in length.
• Semi-transparent and yellowish becoming red-banded to orange with maturity and pink immediately before pupation.
• Cylindrical.
• Legs, prolegs, and hook-like structures (crochets) are absent.

Eggs

• 0.41 mm (0.016 in.) in length and 0.28 mm (0.01 in.) in width.
• Whitish.
• Elongate and flat against the host planthost plant:
  the plant the provides sustenance for an insect
  epidermis.

Hosts

Citrus hosts

All citrus and their hybrids, but the following are specifically identified in scientific literature:

• common mandarins (including tangerine), Citrus reticulata
• grapefruit, Citrus paradisi
• lemon, Citrus limon
• pummelo, Citrus maxima

Non-citrus hosts

• apple, Malus domestica
• cherry, Prunus avium
• cotton, Gossypium hirsutum
• kiwi, Actinidia chinensis
• oleander, Nerium oleander
• olive, Olea europaea
• peach, Prunus persica
• plums, Prunus salicina
• pepper, Capsicum annuum
• papaya, Carica papaya
• walnut, Juglans regia
• willow, Salix lasiolepsis

Host damage

Fruits

Larvae tunnel within rind of fruit. The damage is cosmetic and makes fruit unacceptable for sale as fresh fruit.

Biology

Eggs are laid directly on the fruit, and when they hatch, the larvae tunnel within the rind of the fruit. The larvae pupate outside the mines in silken cocoons with small spheres on the exterior. Citrus peelminer has a short developmental time enabling it to produce 6 - 13 generations per year in California. It can complete its life cycle in 29 days at 26 °C (79 °F).

Oleander and willow are considered alternate hosts since the insect is usually found mining into the stems of these plants as well as citrus during the California winter season. In California, pummelos are usually infested by citrus peelminers in late June through late July. Oranges are infested August through December.

References

Citrus Research Board, California Department of Food and Agriculture and the University of California Center for Exotic Pest Research. 2010. Citrus peelminer: Marmara (new species). (http://www.cdfa.ca.gov/phpps/ipc/biocontrol/pdf/insects/cpeelminer_bio.pdf).

Statewide IPM Program, Agriculture and Natural Resources, University of California. 2011. University of California, pest management guidelines - citrus: citrus peelminer. UC-ANR Publication 3441 (http://www.ipm.ucdavis.edu/PMG/r107301111.html).

Stelinski, L.L. 2011. Featured creatures fact sheet: Citrus peelminer, Marmara gulosa Guillèn and Davis (Insecta: Lepidoptera: Gracillariidae). Publication EENY-415. University of Florida. (http://entnemdept.ufl.edu/creatures/citrus/citrus_peelminer.htm).

Authors

Weeks, J.A., A.C. Hodges, and N.C. Leppla