Plant Doctor Training
Common pests and diseases of Orange
Common pests and diseases of Orange
Angular leaf spot
(FUNGUS -Pseudocercospora angolensis )
Citrus scab
(FUNGUS - Elsinoe fawcetti )
Leaf spots - light brown or greyish, circular (up to
10 mm), mostly solitary , usually surrounded a
prominent yellow halo
Fruit spots - circular to irregular. In young fruits the
spots become hard and raised surrounded by a
yellow halo. Centre of spots often cracked
Leaf spots – cream to tan wart -like outgrowths,
circular or irregular with sunken centres, mostly
along the main veins on the lower leaf surface.
Leaves can become misshapen stunted or
puckered
Fruit spots - circular to irregular raised corky areas
or crater -like outgrowths
Black spot
(FUNGUS - Gui gnardia citrocarpa )
Citrus canker
(BACTERIA -Xanthomonas citri subsp. citri I)
© Jeffrey W. Lotz, Florida Department of Agriculture and Consumer Services, Bugwood.org
Fruit spots - small, round, sunken with gray centres
and brick -red to chocolate brown margins. Green
halos are often seen around the lesions.
Fungal bodies appear as slightly raised black dots
in the centre of lesions. They usually appear as fruit
begins t o colour
Leaf spots – young spots are small blister s
surrounded by a yellow ring. Older spots turn tan
to brown, and have a water -soaked margin
surrounded by a yellow ring. The centre of the
lesion becomes raised and corky.
Fruit spots - Young lesions a re raised, blister -like,
tan, surrounded by yellow halos, depending on fruit
maturity Older spots are circular dark brown to
black with brown to black sunken, corky centres
Plant Doctor Training
Common pests and diseases of Orange
Common pests and diseases of Orange
Zinc deficiency
(NUTRIENT DEFICIENCY – Zinc )
Citrus greening
(BACTERIA – Candidatus Liberibacter africanus)
Occurs first on new growth and remains on leaf as it
matures. Early stages appear as small blotches of
yellow between green veins on the leaf.
Under severe deficiency, leaves become
increasingly yellow except for the green venial areas
Leaves will be small with narrow pointed tips on
terminal growth.
Leaf symptoms - Blotchy mottle (random pattern
of yellowing on leaves that is not the same on the
right and left sides of the leaf , yellow veins, vein
corking or green is lands
Fruit symptoms - Lopsided, misshapen or small
green fruit. Bitter taste with small aborted seeds
Tree symptoms - Yellow shoots, stunting, twig
dieback
Citrus thrips
(INSECT - Scirtothrips aurantii ) © Eric Boa
Orange dog fly
(INSECT - Papilio demodocus )
Citrus thrips are tiny (0.7 to 1 mm in length), orange
yellow insects
Thrips feeding causes brown circular rings of russet
marks around the stem of the fruit
Young caterpillars are brownish with white patches
and are spiny.
Fully grown caterpillars are about 4.5 cm long
green with light markings and eye -like spots
towards the head of the body.
