Causes of Fruit Damage

On this page
  • Avocado thrips
  • Anthracnose
  • Caterpillars
  • Branch canker and dieback
  • Fruit and stem-end rots
  • Genetic mutations
  • Greenhouse thrips
  • Latania scale
  • Mechanical injury
  • Nutritional disorders
  • Off-season fruiting
  • Persea mite
  • Phytophthora fruit rot
  • Sooty mold
  • Sunblotch
  • Sunburn
  • Vertebrates
  • Weather extremes
  • Wildland fire

Abiotic disorders, invertebrates, pathogens, and vertebrates can injure avocado fruit. Many disorders or pests can produce more than one damage symptom.

Names link to more information on identification, management or biology.

Click on photos to enlarge
Scarred, scabby, or brown fruit skins

Avocado fruit scarred by avocado thrips
Avocado thrips
Identification tip: Brownish scars, often in a webbed pattern. Feeding from high-populations of avocado thrips.

Mechanical injury
Mechanical injury
Identification tip: Brownish scars from rubbing, symptoms that on the right fruit are called carapace spot. Carapace spot resembles damage from scab fungus (Sphaceloma perseae) that occurs elsewhere, but scab disease is not reported in California.
Mechanical injury
Mechanical injury
Identification tip: Brownish scars from wind and twig abrasion.

Feeding damage caused by avocado thrips in low populations
Avocado thrips
Identification tip: Slight scarring, or light brown streaks on fruit near the stem. Feeding damage by a low population of avocado thrips.

Young avocado fruit damaged by omnivorous looper.
Omnivorous looper
Identification tip: Scattered brown scars and shallow oval gouges from caterpillar feeding on fruit skins.

Mechanical injury to fruit
Mechanical injury
Identification tip: Brown scars including mechanical injury to a fruit that is pale yellow (left) from a lack of light because it grew in dense leaf litter.

Specked, spotted, fouled, or discolored skins—Top of page
Pale adult female latania scales
Latania scale
Identification tip: Grayish armored scale covers encrusting fruit surface.
Identification tip: Black lesion spots and specks on fruit that can appear while fruit are on the tree or not until later after harvest.
Identification tip: The exposed side of sunburned fruit initially develops pale yellowish discoloration, which later can darken in the center.
Thrips colony on bottom of fruit
Greenhouse thrips
Identification tip: Brownish or pale discoloration on the skin. Fruit may be covered with black specks of greenhouse thrips excrement.
Crop damage by avocado mite
Persea mite
Identification tip: Necrotic spots in fruit skin, uncommon damage by persea mites that usually feed only on leaves and commonly cause foliage spotting and premature leaf drop.
Sooty mold on an avocado fruit
Sooty mold
Identification tip: Blackish fungal growth on surfaces contaminated with honeydew excreted by mealybugs, soft scales, or whiteflies.
Black or discolored large blotches on skin or decayed fruit—Top of page
Wildland fire
Wildland fire
Identification tip: Large circular necrotic blotch, usually on the bottom end of fruit. Resembles damage from fruit rots and sunburn.
Identification tip: Discolored circular blotch from heat damage to exposed fruit, often beginning near top of fruit.
Dothiorella fruit rot
Fruit rot
Identification tip: Shriveled dry or soft and decayed fruit. Skin may be covered with patches of brown to purplish spores from fungi that also commonly cause trunk cankers and limb dieback.
Phytophthora fruit rot
Phytophthora fruit rot
Identification tip: Black soft fungal decay, often in a roundish blotch, frequently near the bottom of fruit. Usually develops only after harvest, and then rots fruit flesh.
Stem end rot
Stem end rot
Identification tip: Fruit decay or dark rot that develops after harvest due to infection by various various fungi, including those causing anthracnose and fruit and stem-end rot.
Necrotic indentation in fruit
Identification tip: Black or necrotic indentations in fruit. In coastal growing areas occurs after weather suddenly changes from cool to hot.
Chewed or gouged fruit—Top of page

Caterpillar damage to fruit.
Identification tip: Brown to blackish, circular to irregular indentations or streaks chewed in fruit by amorbia (western avocado leafroller), omnivorous looper, or orange tortrix

Omnivorous looper feeding damage
Omnivorous looper
Identification tip: Gouged fruit skins from caterpillar chewing, often forming brownish pits. Nearby leaves also are usually chewed.

Discolored indented streaks on avocado fruit from a tree infected with avocado sunblotch
Identification tip: Indented or discolored streaks in skins from a complex of viroids. Sunblotch can also deform fruit and streaks on green branches, have a willowy canopy and/or alligator bark.

Coyote or dog chewing
Coyote or dog
Identification tip: Distinctive triangular canine tooth marks chewed in fruit.

Deep chewing on a ripe, fallen avocado fruit
Roof rat
Identification tip: Deep chewing on a ripe, fallen avocado fruit (left) and shallow chewing on a green fruit picked from a tree. Opossums, raccoons, tree squirrels, and certain other vertebrates cause similar damage.
Mechanical injury
Mechanical injury
Identification tip: Chain saw pruning caused brownish gouges on fruit.
Abnormally shaped or distorted fruit

Identification tip: Abnormally elongate fruit lacking a seed pit. A genetic mutation called ‘cuke’ because fruit resemble cucumbers.  It’s more common on varieties like Fuerte.

Off-season fruiting
Off-season fruiting
Identification tip: Abnormally round fruit, which can also be caused by zinc deficiency. The dark patches are leaf shadows.

Embossment or sectional chimera.
Embossment or sectional chimera
Identification tip: A raised, dark ridge in fruit skin caused by genetic mutation.

Identification tip: Deformed, streaked, or discolored fruit from pathogenic viroids.

Crick or crick-side.
Crick or crick-side
Identification tip: A depressed, often black, indentation on the stem end of avocado fruit. Cause unknown, possibly due to high temperatures or water stress.

Woody avocado
Woody avocado
Identification tip: A hard brown, gnarled structure superficially resembling an avocado fruit. The cause is unknown.

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