Home and Landscape

Causes of Fruit Damage

Scarred, Scabby, or Brown Fruit Skins

Cluster of avocado fruits with extensive brown scarring from avocado thrips. Fallbrook, San Diego Co. Credit: David Rosen
Avocado fruit scarred by avocado thrips, Scirtothrips perseae. Credit: David Rosen

Avocado thrips

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

Close-up of avocado damaged with brown scars on green fruit near stem from avocado thrips, Scirtothrips perseae, feeding. Ventura Co. by JKC Credit: Jack Kelly Clark, UC IPM
Close-up of brown scars on avocado fruit from avocado thrips feeding. Credit: Jack Kelly Clark, UC IPM

Avocado thrips

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

Mechanical injury from wind causing fruit abrasion. Longitudinal brown scars and carapace-spot or angular cracks on avocados. Ventura Co. Credit: David Rosen
Avocado fruit with mechanical injury from wind causing fruit abrasion. Credit: David Rosen

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.

Avocado with longitudinal brown scar from wind causing fruit abrasion with adjacent twig, mechanical injury. Carpinteria, Santa Barbara Co., CA. Credit: David Rosen
Avocado scarred from wind-caused abrasion with an adjacent twig. Credit: David Rosen

Mechanical injury

Identification tip: Brownish scars from wind and twig abrasion.

Pale fruit from lack of light with brown scars from mechanical injury (left) long brown scars from mechanical injury (right), two avocados held in hand. Ventura Co. Credit: David Rosen
Brown mechanical injury scars on the surface of an avocado fruit pale yellow from lack of light (left) beside a normally green fruit with long scars from mechanical injury. Credit: David Rosen

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 shade.

Western avocado leafroller chewing (left) and brown scars from caterpillars, abrasion, or injury (right) on avocado fruit. San Diego Co. Credit: David Rosen
Avocado fruit with damage caused by western avocado leafroller, Amorbia cuneana (left) and brown scars from caterpillars, abrasion, or other physical injury (right). Credit: David Rosen

Omnivorous looper

Identification tip: Scattered brown scars and shallow oval gouges from caterpillar feeding on fruit skins.

Specked, Spotted, Fouled, or Discolored Skins

Latania scale pale females on two hanging green avocado fruit, distant view. R.J. Gill ID CDFA 1175624 San Diego. Credit: David Rosen
Pale adult female latania scales, Hemiberlesia lataniae, on avocado fruit. Credit: David Rosen

Latania scale

Identification tip: Grayish armored scale covers encrusting fruit surface.

Greenhouse thrips colony on the bottom of an avocado fruit. Credit: Phil A. Phillips
Thrips colony on the bottom of a fruit. Credit: Phil A. Phillips

Greenhouse thrips

Identification tip: Brownish or pale discoloration on the skin. Fruit may be covered with black specks of greenhouse thrips excrement.

Anthracnose black specks or lesions on fruit caused by fungal infection. Two avocados held in hand. Ventura Co. Credit: David Rosen
Avocado fruit with black specks or lesions of anthracnose, caused by Colletotrichum gloeosporioides. Credit: David Rosen

Anthracnose

Identification tip: Black lesion spots and specks on fruit that can appear while fruit are on the tree or not until later after harvest.

Dark brown mottling on surface of several avocado fruit Credit: Jack Kelly Clark, UC IPM
Dark mottling on avocado fruit caused by persea mite, Oligonychus perseae. Credit: Jack Kelly Clark, UC IPM

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.

Yellow, brown, chlorotic, and necrotic blotch on sunburned avocado fruit, close up. Fallbrook, San Diego Co. Credit: David Rosen
Necrotic blotch on a sunburned avocado fruit. Credit: David Rosen

Sunburn

Identification tip: The exposed side of sunburned fruit initially develops pale yellowish discoloration, which later can darken in the center.

Blackish sooty mold on green avocado fruit, close-up. Fruit from tree infested with avocado thrips, lace bug, and various Homoptera. Pauma Valley, San Diego Co. Credit: David Rosen
Sooty mold on an avocado fruit from an insect-infested tree. Credit: David Rosen

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

Large black lesion from wildland fire, damage on avocado skin near bottom of two fruit held in hand. Ventura Co. Credit: David Rosen
Avocado fruit with black lesions caused by a wildland fire. Credit: David Rosen

Wildland fire

Identification tip: Large circular necrotic blotch, usually on the bottom end of fruit. Resembles damage from fruit rots and sunburn.

Phytophthora fruit rot black circular area on fruit identical to symptoms commonly caused by P. citricola. Two avocados held in hand. Ventura Co. Credit: David Rosen
Phytophthora fruit rot: black circular area on an avocado fruit. Credit: David Rosen

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.

Black and yellow lesion from wildland fire (left) and black, red, and yellow discoloring from sunburn (right), on fruit held in hand. Ventura Co. Credit: David Rosen
Avocado fruit with a black and yellow lesion from wildland fire (left) and fruit with black, red, and yellow discoloration from sunburn (right). Credit: David Rosen

Sunburn

Identification tip: Discolored circular blotch from heat damage to exposed fruit, often beginning near top of fruit.

Stem end rot, causes include Botryosphaeria dothidea =Dothiorella gregaria, Alternaria spp. Dark decay with well-defined margin exposed in fruit cut open. Ventura Co. Credit: David Rosen
An avocado fruit cut in half showing dark decay with a well-defined margin. Fruit and stem-end rot, caused by various fungi in the Botryosphaeriaceae family and Colletotrichum spp. Credit: David Rosen

Stem end rot

Identification tip: Fruit decay or dark rot that develops after harvest due to infection by various fungi, including those causing anthracnose and Dothiorella fruit rot.

Hand holding dark, shriveled avocado decayed by Dothiorella fruit rot spores visible as brownish discoloration on fruit. San Diego County. Credit: David Rosen
Avocado decayed by Fruit and Stem-end Rot (Dothiorella fruit rot). Note fungal spores visible as a brown discoloration on the fruit. Credit: David Rosen

Dothiorella 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.

Crick or crick-side, depressed black indentation on stem end of fruit. Cause may be high temperatures, water stress. Two avocados held in hand. Ventura Co. Credit: David Rosen
Crick or crick-side, a depressed black indentation on the stem ends of avocado fruit, possibly caused by high temperatures or water stress. Credit: David Rosen

Crick-side

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

Damage caused by Amorbia (left) and omnivorous looper (right). Credit: Max E. Badgley
Damage caused by Amorbia on the left and looper on the right. Credit: Max E. Badgley

Caterpillars

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

Coyote, chewing damage and teeth marks on dropped fruit, 'Reed' avocado. National City, San Diego Co. Credit: David Rosen
Avocado damaged by a coyote, Canis latrans. Credit: David Rosen

Coyote or dog

Identification tip: Distinctive triangular canine tooth marks chewed in fruit.

Shallow holes chewed in the surface of young fruit; from Ventura Co. Credit: Suzanne Paisley
Young avocado fruit damaged by omnivorous looper larvae. Credit: Suzanne Paisley

Omnivorous looper

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

Extensive deep chewing on ripe, fallen fruit (left), shallow chewing on green fruit picked from tree (right). Hand holding roof rat damaged avocados. Ventura County. Credit: David Rosen
Deep chewing on a ripe, fallen avocado fruit (left) and shallow chewing on a green fruit picked from a tree (right), examples of damage by roof rat, Rattus rattus. Credit: David Rosen

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.

Depressed, indented yellow and black streaks on fruit hanging in cluster from tree infected with avocado sunblotch viroid (ASBVD). Ventura Co. Credit: David Rosen
Discolored indented streaks on avocado fruit from a tree infected with avocado sunblotch viroid (ASBVD). Credit: David Rosen

Sunblotch

Identification tip: Indented or discolored streaks in skins from a complex of viroids. Sunblotch can also deform fruit and injure trees.

Chain saw injury. Fruit with long brown indented scars caused during tree pruning. Avocado held in hand. Ventura Co. Credit: David Rosen
Chain saw pruning injury to an avocado fruit. Credit: David Rosen

Mechanical injury

Identification tip: Chain saw pruning caused brownish gouges on fruit.

Abnormally Shaped or Distorted Fruit

Elongate avocado fruit, and fruit sliced to reveal the lack of a seed pit, a genetic mutation called 'cuke' on green skin 'Fuerte' avocado, held in hand. San Diego Co. Credit: David Rosen
Avocado fruit sliced to reveal the lack of a seed pit, a genetic mutation called 'cuke.' Credit: David Rosen

Cuke

Identification tip: Abnormally elongate fruit lacking a seed pit. A genetic mutation called ‘cuke’ because fruit resemble cucumbers.

Deformed green fruit with depressed, indented yellow streak hanging from tree infected with avocado sunblotch viroid (ASBVD). Santa Barbara Co., CA. Credit: David Rosen
Avocado fruit deformed and streaked from avocado sunblotch viroid. Credit: David Rosen

Sunblotch

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

Round avocado fruit, deformation characteristic of off-season fruiting, two adjacent fruit hanging from tree in patchy light. Carpinteria, Santa Barbara Co., CA. Credit: David Rosen
Round avocado fruit, a deformation characteristic of off-season fruiting. Credit: David Rosen

Off-season fruiting

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

Crick or crick-side, depressed black indentation on stem end of fruit. Cause may be high temperatures, water stress. Two avocados held in hand. Ventura Co. Credit: David Rosen
Crick or crick-side, a depressed black indentation on the stem ends of avocado fruit, possibly caused by high temperatures or water stress. Credit: David Rosen

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.

Embossment or sectional chimera, a raised, dark ridge on fruit caused by genetic mutation. One avocado held in hand. Ventura Co. Credit: David Rosen
Avocado fruit with embossment or sectional chimera, a raised, dark ridge caused by genetic mutation. Credit: David Rosen

Embossment or sectional chimera

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

Woody avocado. Gnarled, cauliflowerlike, hard brown structure superficially resembling an avocado fruit, cause unknown. San Diego. Credit: David Rosen
The cause of woody avocado, a hard brown structure superficially resembling an avocado fruit, is unknown. Credit: David Rosen

Woody avocado

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

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