Fungal diseases of fruit crops-Grapes

1. Fungal diseases of Fruit crops-
Grapes
Vaishali S.Patil
Assosiate Professor, Department of Botany
Shri Shivaji College of Arts, Commerce & Science Akola

2. 1.Alternaria rot/ Leaf Blight and Bunch Necrosis caused
by Alternaria alternata
Symptoms- The disease attacks both leaves and fruits. Small
yellowish spots first appear along the leaf margins, which
gradually enlarge and turn into brownish patches with
concentric rings. Severe infection leads to drying and
defoliation of leaves. Dark brown-purplish patches appear on
the infected berries, rachis and bunch stalk just below its
attachment with the shoots.
Control- Fungicides.

3. 2.Angular leaf scorch caused by Pseudopezicula tetraspora,
Phialophora
Symptoms- Lesions are initially yellow or reddish and
confined by major veins. They later become necrotic and
surrounded by yellow or red margins. Late-season infections
may look like freckled spots and can cause premature
defoliation. Infected flower clusters dry up. The pathogen
overwinters in fallen infected leaves.
Control- Fungicide

4. 3.Angular leaf spot caused by Mycosphaerella angulata,
Cercospora brachypus
Symptoms- Faded angular spots on the leaves. The spots
quickly darken to brown and may be surrounded by a distinct
halo.Leaf loss due to angular leafspot can result in poor fruit
quality.
Control- Resistant varieties, clean seed, rotation, Use drip
irrigation, remove and destroy infected fruit and vines,
fungicide

5. 4. Anthracnose and bird's-eye rot caused by Elsinoe ampelina,
Sphaceloma ampelinum
Symptoms- Dark red spots on the berry, later these spots become
circular, sunken, ashy-gray and in late stages surrounded by a dark
margin which gives it the “bird’s-eye rot” appearance.It also attacks
shoots, tendrils, petioles, leaf veins, and fruit stems. Numerous spots
sometimes occur on the young shoots. These spots may unite and girdle
the stem, causing death of the tips. Spots on petioles and leaves cause
them to curl or become distorted.
Control- cankers should be removed while pruning,should be burnt or
buried deep in the soil, fungicides.

6. 5. Armillaria root rot (shoestring root rot) caused by
Armillaria mellea, Rhizomorpha subcorticalis
Symptoms- stunted shoots, yellow or red leaves, wilting and
premature defoliation. when vines may completely collapse
and die. White, feltlike fungal mats occur below the bark near
the soil line. Infected tissues have a distinct mushroomlike
odor when moist. Black, shoestringlike strands (rhizomorphs)
may be present on bark and in the soil
Control- removal of decay of roots, clear the soil of stumps
and large roots, ry to burn all woody debris and leave the
ground fallow for at least 1 year, soil fumigation, fungicide

7. 6.Aspergillus rot/ Black Rot caused by Aspergillus niger
Symptoms- The pulp of infected berries is reduced is
reduced to watery consistency.
Control- Careful handling and prompt refrigeration

8. 7.Black rot/Black mould of grapes caused by Guignardia bidwellii
Symptoms-The disease attacks the leaves, stem, flowers and berries. All
the new growth on the vines prone to attack during the growing season.
Irregularly shaped reddish brown spots appears on the leaves and a black
scab on berries. Occasionally, small elliptical dark coloured canker
lesions occur on the young stems and tendrils. Leaf, cane and tendril
infection can occur only when the tissue is young, but berries can be
infected until almost fully-grown. The affected berries shrivel and
become hard black mummies.
Control- Mummified berries left on vines should be collected and
destroyed, free circulation of air, fungicides.

9. 8. Botrytis Bunch Rot (Grey Rot or Noble Rot) caused by Botrytis
cinerea
Symptoms-The infected fruit may become covered with a grayish-tan
powder containing the spores of the fungus.Berry stems and cluster
stems may be invaded, causing them to shrivel,decays berries low in
sugar, the rotting berry has a sour odor and taste.If the berries are nearly
mature and have a high sugar content, the decaying berry is quite firm,
dry, and somewhat sweetish to the taste.
Control- Careful handling in the field, precooling and
refrigeration helps in controlling the disease. Pruning and
thinning of the vineyard reduces humidity around the clusters,
fungicides.

10. 9.Bot canker caused by Lasiodiplodia theobromae,
Botryosphaeria rhodina
Symptoms- Foliar symptoms may be observed as mild
chlorosis or wilting due to inhibition of water transport.
Control- remove and replace the vine. Avoid large pruning
cuts when possible; avoid pruning during and before wet
weather.

11. 10.Downy mildew caused by Plasmopara viticola
Symptoms-The fungus is an obligate pathogen which can attack all
green parts of the vine.
Infected leaves develop pale yellow-green lesions which gradually turn
brown. Severely infected leaves often drop prematurely.Infected petioles,
tendrils, and shoots often curl, develop a shepherd's crook, and
eventually turn brown and die.Young berries are highly susceptible to
infection and are often covered with white fruiting structures of the
fungus. Infected older berries of white cultivars may turn dull gray-
green, whereas those of black cultivars turn pinkish red.
Control- All affected portions of the vine should be removed at the time
of pruning and destroyed immediately, fungicides.

12. 11.Powdery mildew caused by Erysiphe necator (Uncinula necator)
Symptoms-Diseased leaves appear whitish gray, dusty, or have a
powdery white appearance. Petioles, cluster stems, and green shoots
often look distorted or stunted. Berries can be infected until their sugar
content reaches about 8%.If infected when young, the epidermis of the
berry can split and the berries dry up or rot. When older berries are
infected, a netlike pattern often develops on the surface of the berry.
Control- Fungicides

13. 12.Greenaria bitter rot caused by Greenaria uvicola
Symptoms- This fungus can infect all green parts of the vine including
leaves, tendrils, new shoots, as well as berries. Infections of leaves first
appear as red spots on the upper leaf surface. These circular spots enlarge
and become tan to light brown with distinct, dark borders. Small,
pinpoint black fruiting structures of the fungus often develop in the
centers of these spots.Most serious damage usually occurs on the berries.
On the fruit, infections first appear as whitish spots which enlarge to
sunken areas with dark borders, the fruit becomes black, wrinkled,
mummified, and look like raisins. Infected grapes often shatter, leaving
only the stem.
Control- Pruning of the canes followed by fungicides.

14. 13.Blue mould rot caused by Penicillium digitatum
Symptoms -Scanty growth - white and turn bluish green are seen.Decay
the berries.Infected tissues become soft and watery.Infected berries emit
a mouldy flavor.The fungus covers whole berries and it looks like bluish
green in colour.
Control- fumigation, fungicides

15. 14.Green mould rot caused by Penicillium digitatum
Symptoms-Infected berries are discolored yellowish green, and affected
fruits shrivel.
Masses of powdery green spores generally covered the bunch of grapes.
Control- Proper dormant pruning and destruction of canes, clusters, and
other plant parts, canopy management during the season can help to
increase airflow.

16. 15.Rhizopus rot caused by Rhizopus stolonifer
Symptoms-Round irregular, light brown and water soaked lesion appear
on fruits. Decaying fruits emits fermented, moudly smell.The fungus
grows rapidly producing acoarse grey mat of mycelium.
Control- fungicides, removing of diseased berries ,avoiding injury to the
berries.

17. 16.Rust caused by Phakopsora vitis
Symptoms-Numerous orange coloured pustules on the lower
surface of the leaves. In case of severe infection such pustules
cover the entire leaf surface leading to severe defoliation.
Control- Fungicides

18. 17.Foot rot caused by Cylindrocarpon
Symptoms-Roots show black, sunken, necrotic lesions. In cross section,
the base of the trunk appears necrotic and xylem vessels may be black in
colour.Leaves may appear to be water stressed or scorched, and vines
may be stunted and/or killed.
Control- fungicides

19. 18.Phomopsis leaf spots/ Dead Arm caused by Phomopsis viticola
Symptoms-Angular small spots on the leaves, stems, canes and flower
clusters. Most of the spots have yellowish margins with dark centres.
Frequently the spots grow together and form large brown areas on the
canes. Later on the canes start to dry rapidly. In severe cases the fungus
spreads on the woody part where it gradually attacks the water
conducting tissues. In case of severe infection the drying extends to the
roots and the whole plant wilts.
Control-The pruned canes should be collected and destroyed, fungicides

20. 19.Summer Bunch Rot (Sour Rot) caused by Aspergillus niger,
Alternaria tenuis, Botrytis cinerea, Cladosporium herbarum,
Rhizopus arrhizus, Penicillium spp., and others.
Symptoms-Sour rot showing bluish sporulation typical of Penicillium
infection on grapes. Affected berries drip juice and smell like vinegar.
Control- Basal leaf removal at or after berry set, proper irrigation,
fertilizer, fruit thinning, and canopy management practices.

21. 20.Eutypa Dieback caused by Eutypa lata
Symptoms-Following delayed emergence in the spring, shoots on older
vines are stunted and have shortened internodes. Leaves look tattered and
chlorotic. Dark, wedge-shaped cankers develop in vascular tissue. Black
stromata containing fungal fruiting bodies called perithecia may occur on
the surface of dead wood. Necrosis of wood tissue as a result of Eutypa
infection surrounding a pruning wound.
Control-Sanitation, avoid pruning during and before wet weather,
Remove diseased wood, fungicides

22. 21.Macrophoma Rot caused by Botryosphaeria dothidea
Symptoms-As grapes mature, lesions develop that are dark and can be
sunken. Fruiting bodies of the fungus will form in scattered patterns
within the lesions. Lesions can continue to expand, resulting in a watery
rot of the berry. Infected fruit will drop from the cluster, becoming
shriveled and hollow. Pycnidia that form during the current season can
serve as reservoirs for spores that can cause new infections.
Control-Sanitation, Proper dormant pruning and destruction
of canes, clusters, and other plant parts , increase airflow , shoot
positioning and strategic leaf pruning, fungicides.

23. 22.Phymatotrichum Root Rot, Cotton Root Rot, Texas Root Rot
caused by Phymatotrichopsis omnivora
Symptoms- Plants may appear somewhat stunted, wilting and foliar
discoloration, In severe cases, defoliation can occur, and fruit can
become sunburned due to exposure, nfected plants may be killed or
survive and continue to decline slowly
Control- Avoid locations where cotton or alfalfa was grown previously,
Planting sites with a soil pH below 6.5