Colletotrichum gloeosporioides causes anthracnose disease in citrus plants. It can infect leaves, flowers, and fruits, causing circular light tan lesions on leaves and brown to black spots on fruits. The fungus spreads via airborne spores that are dispersed by water splashes. High humidity from 24-28°C and frequent rains promote disease development. Management strategies include pruning infected plant parts, fruit bagging, and fungicide sprays to control the disease.
SIGNIFICANCE
Post harvestloses in citrus in several tropical countries
ranges from 15%.
In China and Brazil it recorded first – Sao Paulo state
(Brazil).
The incidence of this disease reach 100% in fruit under wet
conditions.
4.
DISTRIBUTION
World
Pakistan, Brazil,China, India and also worldwide
in distribution.
India
Himachal Pradesh, Tamil Nadu, Karnataka, Andhra
Pradesh etc.,
5.
SYMPTOMS ON LEAVES
Common symptoms are a more or less circular, flat
area, light tan in color with a prominent purple
margin that at a later phase of infection will show the
fruiting bodies of the fungus (tiny dispersed black
flecks).
SYMPTOMS ON FLOWERS
Infections on the flowers (form clusters) start as
small black or dark- brown spots.
These can enlarge, coalesce and kill the flowers.
They starts disintegration.
SYMPTOMS ON FRUITS
Fruit- anthracnose usually only occurs on fruit that
have been injured by other agents.
The lesions are brown to black spots of 1.5 mm or
greater diameter. The decay is usually firm and dry
but if deep enough can soften the fruit.
PATHOGEN CHARACTERS
Conidiophore issimple, hyaline, branched hypha on
which conidia are produced.
Conidia is thin walled with large number of oil
globules.
Dissemination
Conidia aredispersed passively by splashing of rain or
irrigation water.
Symptoms and disease development
Black, sunken, rapidly expanding lesions develop in fruiting
bodies (Acervuli).
Pathogen survival
The pathogen survives between seasons on infected and
defoliated branch terminals and mature leaves.
16.
MODE OF INFECTION
Primary spread
Air borne conidia and innoculums present in the
seeds are source of primary infection.
Secondary spread
Spores spread through rain splashes and
irrigation water and also by infected debris.
17.
FAVOURABLE CONDITIONS
Highhumidity
Temperature of 24°C – 28°C.
Frequent rains.
Moist conditions favours the development of
disease (October to November).
18.
INTEGARATED DISEASE MANAGEMENT
Pruningof infected leaves, twigs and fruits.
Fruit bagging at fruit set stage (late Oct – early Nov)
Spray twice with Carbendazim (0.1%) at 15 days
interval during flowering to control blossom
infection.
19.
Spraying ofMancozeb 2 g/lit Thiophanate methyl 1 g/lit or
chlorothalonil 2 g/lit 3 times at 15 days interval.
Spray copper fungicides (0.3%) for the control of foliar
infection.
Post harvest treatment with Benzimidazole may reduce fruit
loss.
20.
REFERENCES
• Saha.L.R, ’Handbookof plant Diseases’ 2002, Kalyani
publishers, New Delhi.
• Thind.T.S, “Disease of fruits and vegetables and their
management”, Kalyani publishers second edition
2016,New Delhi.
• https://www.plantnatural.com>anthracnose
• idtools.org>citrus>diseases>factsheet