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What is it?
Anthracnose in grapes is caused by elsinoe ampelina, a fungus. It primarily infects the plants doing sever damage for two or three years consecutively and then may disappear.
What does it look like?
Elsinoe ampelina damage shows up at first as yellowish areas on the leaves and which appear as if they are sunken in spotted areas with light grayish centers to them. The grape leaves quickly dry out and turn brownish developing dark brown borders on the affected spots. Additionally, the appearance of these same circular spots is not uncommon on the shoots, leafstalks, tendrils and fruit. Although infected fruit will still remain firm, the leaves around it may turn brown and drop off or wilt and curl downward. The areas of fungal infection start quite small and spread in size rapidly.
How does it manifest?
Elsinoe ampelina is primarily present in regions where the temperature remains around 70° to 80°. Considerable damage may be apparent on the grape plants for two or three years in a row, and then it seems to disappear. This fungal infection is also known as bir’d eye disease because the spots tend to look similar to a bird’s eye. Anthracnose also thrives in areas that have frequent, regular rainfall. Anthracnose can attack all above ground sections of the plant including the fruit itself, the stems and the leaves. It is very destructive to these plants in a quick period of time and the plants will die off quickest when the weather is most humid as this is when the fungus spreads rapidly. However, it is usually not a severe disease on Concord grapevines. Once plants have been infected the spores can overwinter on plant debris and old canes. You will see the most evidence of anthracnose in poorly maintained vineyards which are already at risk andThen when spring rains arrive the splashing water quickly spreads the Elsinoe ampelina to new, previously healthy vines. Anthracnose attack over a period of two or three years weakens grape vines and may result in misshapen fruit or weaken them to the point that they are prone to other infections and damage.
What can you do about it?
Lime sulfur containing fungicide is effective in controlling the spread of the disease if applied when you first notice signs of damage. However, you may need to repeat applications of the fungicide several times as seven day intervals before you contain the disease and rid the plants of the fungi. It is best to treat plants which have been previously infected with ferbam containing funcgicide, the next spring when the shoots are between 2 and 10 inches long. Plants may become reinfected if you have not killed off all of the fungus and the weather becomes warm, wet and humid again. Additionally, discard any infected fruit and canes. that can be planted.
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