PESTS OF CITRUS
Dr. Jamba Gyeltshen
7/05/08
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Common pests
• Chinese Fruit Fly - Bactrocera minax
• The trunk borer - Anoplophora sp
• Citrus Shield Bug - Rhynchocoris
poseidon
• Citrus Leaf Miner - Phyllocnistes citrella
• Sucking pests - scale insects, aphids,
mealy bugs, black flies
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Chinese Fruitfly
• Puparia remain in soil
for 5 to 7 months
• Adults emerge - late
April to late May
• Become sexually
mature - early June
• Lay eggs- mid June to
late July
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Seasonal phenology of Fruitfly
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Management
• Fortnightly protein bait spray applications from early May to late July
would reduce the fly population markedly and prevent oviposition in
developing fruit.
• Because the oviposition period is well defined, from mid June to late
July, a systemic insecticide cover spray in early July followed up by
a second treatment in late July, would provide high mortality of eggs
in fruit.
• The extended period between fruit fall and pupation, at least 18
days, would provide opportunity for cultural control practices.
Collection of fallen fruits only once every ten days would prevent the
development of puparia and thus reduce the fly population for the
next year.
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Citrus Trunk borer
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Trunk borer
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Eggs laid between June and August
Eggs deposited in the bark of trunk and large branches
Each female lays 1-5 eggs under the bark
Larvae feed between the bark and wood
Young trees are ring barked
Larvae later tunnel into the wood
Sawdust like frass observed
Life cycle takes 2 years
Larvae pupate in the wood and emerge in April-May
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Trunk borer Management
• Maintain the basin clean
• Regularly inspect the trunks for
any wounds or bulging spots
• Catch and kill adults whenever
spotted
• Poke holes with wire to kill the
larvae
• Plug holes with a cotton
soaked in kerosene, diesel or
petrol.
• Close the hole with a mud
paste or cow-dung
• Remove and burn affected and
unproductive trees
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Citrus Shield Bug
• Lay 12 to 16 eggs on
citrus leaves in summer
• Nymphs take 4-6 weeks
to develop into adult bugs
• Young nymphs stay in
groups (gregarious) often
in neat circles
• Fruits drop as a result of
their feeding
• Fruit drop occur between
April to September
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Citrus Shield Bug
• Natural control takes place: egg
parasitoids, predator (red tree ant)
• Encourage red tree ant
• Destruction of the young nymphs
physically in the morning
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Citrus Leaf miner
Fig. 1. Phyllocnistis citrella Stainton,
adult (4 mm wing spread).
Fig. 2. Adult in resting pose (2 mm)
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Citrus Leaf miner
• Eggs are laid singly on underside of young
leaves
• Larvae make serpentine mines (tunnels)
• Fecal matter is seen as a black trail
• Pupation takes place at the edge of the
leaf
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Citrus Leaf miner
• Serious problem in young trees and
nurseries
• Causes distortion, curling and growth
retardation
• Severe infestation: spraying a systemic
insecticide (Dimethoate)
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Citrus Swallowtail
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Management
• Collection and destruction of larva could
be done in nurseries or in small areas with
limited infestation.
• If its not feasible to handpick and destroy,
insecticides may be applied.
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Sucking pests
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Black citrus aphids
Scale insects
Mealy bugs
Psyllids
Mites
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Scale insects
Glover scale, Lepidoaphis gloveri
Soft brown scale Coccus hesperidum
Florida red scale Chrysomphalus aonidum
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California red scale
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Management
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As far as possible avoid
spraying insecticides
against aphids, scales,
mealybugs and mites.
Horticultural oil sprays
or Tree spray oils are
generally recommended
against sucking pests.
Trunk banding with nondrying sticky glue in
order to deny access of
attending ants to small
Homoptera.
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Summary of Citrus IPM
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Control of trunkborers by hand killing of young borers and plugging holes of older
larvae with wads drenched in diesel or kerosene.
Hand picking of citrus swallowtail, Papilio larvae in nurseries and young trees
Spraying with Actellic or Dimethoate on nurseries infested by the Citrus Leaf Miner
Bait spraying with malathion/molasses against fruit flies in April-August
Collecting and destruction (burning, drowning, deep burying) of dropped fruits
every 10 days interval
Male fruit fly trapping with Cu-lure/Methyl eugenol in isolated orchards.
Conservation/Enhancement of colonies of Red Tree Ants in the southern orchards
against Citrus Shield Bug.
Handkilling of congregations of Citrus Shield Bug nymphs on tree trunks.
As far as possible avoidance of spraying against whiteflies, blackflies, aphids,
scales, mealybugs and mites. Horticultural oil sprays are generally recommended
against sucking pests.
Trunk banding with non-drying sticky glue in order to deny access of attending
ants to small Homoptera.
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