Invertebrate Damage to Leaves
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- California red scale
- Citrus red mite
- Glassy-winged sharpshooter
- Greenhouse thrips
- Sooty mold
- Twospotted spider mite
- Brown garden snail
- European earwig
- Forktailed bush katydid
- Citrus leafminer
- Asian citrus psyllid
- Brown citrus aphid
- Diaprepes root weevil
- Light brown apple moth
Sucking pest damage
Chewing pest damage
Names link to more information on identification and management.
Click on photos to enlarge
California red scale leaf spotting
Identification tip: Look for orange- to-brown
round scale covers on blotchy discolored leaves.
Purple scale also mottles leaves, but its covers are
darker and elongate, resembling tiny mussel seashells.
Mites, thrips, and diseases and disorders also discolor
Citrus red mite stippling
Identification tip: Bleached or pale, speckled
leaves are often caused by citrus red mite feeding. Twospotted
spider mite, Texas citrus mite, Yuma spider mite, and
(rarely) leafhoppers also stipple leaves. Discolored
fruit or silk webbing may be present depending on the
species of mite.
Twospotted spider mite leaf discoloring
Identification tip: Pale yellow-to-brown
dead patches can form in leaf tissue where twospotted
mites feed. Sunburn and other diseases and disorders
can cause similar foliage injury.
Greenhouse thrips bleaching and excrement
Identification tip: Greenhouse thrips foul
plants with dark specs of excrement. Thrips and several
mite species discolor, bleach, or stipple leaves or fruit.
But unlike mites, thrips do not produce silk webbing.
Identification tip: Where dark sooty mold
or sticky honeydew is evident, look for phloem-sucking
Homoptera, including aphids, cottony
cushion scale, citricola
scale, brown soft scale, black
scale, mealybugs (shown
here), and whiteflies. Also look for ants that tend these
Glassy-winged sharpshooter excrement
Identification tip: This whitish, coating
is sharpshooter excrement. Infested leaves may also have
elongate yellowish blisters or brown scars where females
inserted their eggs.
Aphids' leaf distortion
Identification tip: Curled leaves and shoots
are usually harmless if infested by aphids. But look
closely to determine the actual cause as foliage can
be distorted by Homoptera, caterpillars that web foliage,
citrus thrips, citrus leafminer, citrus bud mite (in coastal
lemon), and certain diseases and disorders. Be
alert for the introduction of new pests such as the exotic brown
which is very efficient at vectoring citrus Tristeza
greatly increasing the severity of this disease. Report suspected
new pests to agricultural officials.
citrus psyllid wax debris
Identification tip: This exotic, aphidlike
insect sucks phloem, distorting leaves and shoots. The
yellowish orange nymphs produce abundant white wax. The
brownish adults spread citrus greening disease (Huanglongbing),
caused by a citrus tree-killing bacterium. Report to
agricultural officials any findings of this pest.
citrus aphid honeydew
Identification tip: Shiny honeydew on leaves is caused by
aphids and other phloem-sucking pests. Be alert for the introduction
of new pests such as the exotic brown citrus aphid, which
is very efficient at vectoring citrus Tristeza virus, greatly
increasing the severity of this disease. Report suspected
new pests to agricultural officials.
pest damage—Top of page
Forktailed bush katydid chewing
Identification tip: Leaf chewing, either along
the edges or in the middle of leaves, may be caused by katydids.
If katydids are the cause during spring, the amount of leaf
damage is relatively low. But if young fruit are present,
look for a circular scar near the center of fruit, which
is the economic damage katydids cause. Earwigs, citrus cutworm,
and other species of caterpillars cause similar damage.
Identification tip: Grasshoppers chew foliage,
usually from the leaf edges. Some leaves can be so extensively
chewed that only the main vein remains. Young trees
can be severely defoliated if grasshoppers are abundant.
Damage is most likely on trees growing near unmanaged
vegetation, from which grasshoppers migrate to citrus.
European earwig chewing
Identification tip: Earwigs chew buds, leaves,
or small fruit. Chewing damage can be common on trees
with trunk wrappers, on lower canopy foliage where trees
are not skirt-pruned, and where abundant leaf litter
or other harborage provide earwigs places to hide during
Identification tip: Chewed or ragged leaves,
scraped or pitted fruit and foliage, and silk webbing
on plants are caused by amorbia, citrus cutworm, omnivorous
looper, orange tortrix, and (less often) by larvae of
other moths. If chewed leaves are near fruit, fruit are
also often chewed. Only caterpillars both chew plants
and produce silk webbing.
Diaprepes root weevil chewing
Identification tip: Ragged, notched, or serrated
leaf margins, usually on lower or interior foliage, can
be from Fuller rose weevil or
the exotic Diaprepes
root weevil ;
Diaprepes root weevil chews notches that are larger
and tend to occur more widely throughout the tree.
Unlike Fuller rose beetle, Diaprepes rolls or glues
leaves together where it lays its eggs. Report to agricultural
officials any findings of the exotic Diaprepes root
Brown garden snail chewing
Identification tip: Snails chew irregular
holes in leaves and fruit and produce shiny, dry or wet,
slimy trails on plants
and the ground. Snails feed mostly at night. If they are
the suspected cause of chewing, look for snails where they
rest during the day beneath trunk wraps, in leaf litter,
around irrigation emitters, or attached to leaves or bark.
apple moth larva shelter
Identification tip: Young citrus leaves
and shoots are chewed, rolled, and webbed by several
leafroller species (Tortricidae), including amorbia,
brown apple moth, an exotic pest, also causes
this damage. Pheromone-baited traps are a primary way
to distinguish which species of moth is present. Report
to agricultural officials any findings of this exotic
damage—Top of page
Citrus leafminer mine
Identification tip: Citrus leafminer bores pale
or dark (excrement-filled) winding tunnels just under the
leaf surface. Infested succulent shoots and young leaves
may be distorted, galled, or rolled.
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