Citrus

Invertebrate Damage to Fruit

Sucking pests
  • California red scale
  • Citricola scale
  • Citrus bud mite
  • Citrus mealybug
  • Citrus red mite
  •  
  • Citrus rust mite
  • Citrus thrips
  • Glassy-winged sharpshooter
  • Potato leafhopper
Chewing pests
  • Brown garden snail
  • Caterpillars
  • Citrus cutworm
  • Citrus peelminer
  • European earwig
  • Forktailed bush katydid
Exotic pests
  • Diaprepes root weevil
  • Light brown apple moth
  • Tephritid fruit flies
On this page

Discoloring or shallow scarring of the rind
Deep gouging or chewing of the rind
Surface fouling of the rind, which can be scraped or washed off
Distorted fruit or deep boring in the flesh

Names link to more information on identification and management.

Click on photos to enlarge

Discoloring or shallow scarring of the rind

Citrus thrips scarring
Citrus thrips scarring
Identification tip: Scabby, gray, or silvery scars on the rind, usually at the stem end of the fruit, result from citrus thrips feeding under the calyx when fruit are small. The ring pattern around the button helps to distinguish thrips scars from damage caused by insects or wind scars and other fruit diseases and disorders. When amorbia causes ring scars, the chewing is deeper in the rind.

Citrus peelminer tunnel
Citrus peelminer tunnel
Identification tip: Larvae of a tiny moth cause winding tunnels by feeding just under the top layer of the rind, usually on the inward-facing fruit surface.

Potato leafhopper damage
Potato leafhopper damage
Identification tip: Leafhopper feeding causes roundish discoloring on fruit. Injured blotches are typically clustered in groups. Scars usually develop on older fruit during late summer or fall when leafhoppers migrate into citrus.

California red scale mottling
California red scale mottling
Identification tip: Armored scale feeding can discolor rinds. Look for the orange to brown, roundish covers on twigs or on discolored fruit and leaves. These covers can be removed to reveal the soft-bodied armored scales feeding underneath.

Citrus red mite stippling
Citrus red mite stippling
Identification tip: Bleached, pale, or silverish discoloring on the rind (left in photo) occurs when high citrus red mite populations feed on fruit. Greenhouse thrips, twospotted spider mite, and Yuma spider mite can also bleach fruit.

Citrus rust mite russeting
Citrus rust mite russeting
Identification tip: Rind discoloration varies from dark brown to pale gray, depending on cultivar and maturity of fruit infested by rust mite (also called silver mite). Broad mite, peach silver mite, twospotted mite, red mite, and Yuma spider mite are other mites or spider mites that discolor rinds.

Deep gouging or chewing of the rind—Top of page

European earwig scarring
European earwig scarring
Identification tip: Irregularly shaped chewing on small fruit can be caused by earwigs. Damage is most prevalent on young trees with trunk wraps, on lower canopy fruit of trees that are not skirt-pruned, and where leaf litter or other debris on soil provides pest shelter.

Forktailed bush katydid damage
Forktailed bush katydid damage
Identification tip: Katydid nymph feeding on young fruit causes scars that are deeper than damage from citrus thrips or mechanical injury. Some leaf chewing is usually present where katydids occurred.

Forktailed bush katydid
Forktailed bush katydid
Identification tip: Katydid damage is typically a single circular scar, usually in the midsection of fruit, often on the sheltered side facing in toward the trunk. This injury occurred when a nymph chewed the small, immature fruit.

Caterpillar damage
Caterpillar damage
Identification tip: Fairly deep chewed areas in young fruit, but generally not circular like katydid, can be caused by larvae of several species of large moths, including, California orangedog, citrus cutworm, and orange tortrix. Caterpillars are the only citrus pest that chew both fruit and leaves and (in some species) produce silk webbing.

Light brown apple moth scarring
Light brown apple moth
Identification tip: Young amorbia larvae feed under the calyx of fruit are the common cause of a circular scar around the button. Less often omnivorous leafroller, orange tortrix, and (in Southern California only) pink scavenger caterpillar cause button-end scars. In comparison with scarring by citrus thrips, caterpillar chewing is deeper and webbing may be present. If amorbia-like damage is unusually abundant, suspect the exotic light brown apple moth. Report to agricultural officials any suspected finding of this pest.

Citrus cutworm
Citrus cutworm
Identification tip: Cutworm feeding when the fruit was young caused this irregular scarring. When cutworms chew circular scars, their injury closely resembles katydid damage. Cutworm injury typically forms a meandering pattern, sometimes at multiple locations on a fruit. Katydids usually scar only a single spot.

Caterpillar scars and webbing
Caterpillar scars and webbing
Identification tip: Fruittree leafroller sometimes chews older fruit as shown here. Snails and occasionally other caterpillars (amorbia, omnivorous leafroller, and orange tortrix) also can chew older fruit. Most fruit chewing pests (such as earwigs and katydids) damage only young fruit, but damage that occurred when fruit were young may be overlooked until fruit mature.

Brown garden snail
Brown garden snail
Identification tip: Where snails chewed leaves and gouged fruit, their feces and wet, slimy or dry, silvery trails are often visible on surfaces. Snail shells can be observed during the day on bark, around sprinklers, or by inspecting under trunk wraps, or digging in leaf litter. Snail damage is heaviest on fruit close to the ground.

Diaprepes root weevil
Diaprepes root weevil (PDF)
Identification tip: This large weevil chews leaves and fruit, leaves dark excrement on foliage, and rolls or glues leaves during egg laying. The leaf chewing and immature stages of the Fuller rose beetle are very similar, so positively identify any weevils found in citrus. Report to agricultural officials any findings of the exotic diaprepes root weevil.

Surface fouling of the rind, which can be scraped or washed off—Top of page

Sooty mold
Citricola scale sooty mold
Identification tip: The dark, felty growth from sooty mold can be scraped off of plant surfaces. Where sooty mold occurs, look for aphids, citricola scale, black scale, brown soft scale, cottony cushion scale, mealybugs, and whiteflies that excrete honeydew on which sooty mold fungi grow. Be alert for the introduction of exotic Homoptera, such as the brown citrus aphid. Report suspected new pests to agricultural officials.

Citrus mealybug waxiness
Citrus mealybug waxiness
Identification tip: Citrus mealybugs usually occur in protected places, such as where fruit touch. Several species of mealybug produce pale, waxy material on fruit, leaves, or twigs. Whiteflies and cottony cushion scale also produce whitish material on leaves or twigs, but not on fruit.

Glassy-winged sharpshooter excrement
Glassy-winged sharpshooter excrement
Identification tip: Whitish excrement, often in a runny pattern, is caused by this large species of sharpshooter sucking xylem fluids.

Distorted fruit or deep boring in the flesh

Citrus bud mite
Citrus bud mite on lemon
Identification tip: Feeding within the buds on succulent new growth distorts young lemons, although fruit is usually not this severely misshapen. Feeding and damage occur in buds during the fall and winter, causing injury to spring bloom and the resulting fruit. Bud mite is usually a pest only on coastal lemons.

Fruit fly egg-laying stings
Fruit fly egg-laying stings
Identification tip: Several species of exotic fruit flies cause discolored oviposition scars on the surface when they lay eggs that hatch into pale maggots that feed inside fruit. Mediterranean fruit fly, Mexican fruit fly, and Oriental fruit fly are among the tephritid flies periodically introduced and eradicated in California. Report to agricultural officials any findings of tephritid fruit flies.

 

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