Ash Anthracnose becomes a problem on Ash trees when the conditions are favorable: moist and cool. The moisture helps spread the spores in the spring and the cool weather aids the disease development on the leaves. Once the weather becomes less favorable, spore production and disease development will be greatly reduced. Ash trees that become infected several years in a row may become stunted. Steps can be taken to minimize subsequent infections.
1)Fallen leaves should be raked up and destroyed to minimize further infection.
2)Fertilizing with a high nitrogen will promote optimum refoliation.
3)Apply a protectant spray:
•1st Treatment:
Apply when buds are beginning to swell, right before buds break.
•2nd: Apply when buds show green tips.
•3rd: Apply when leaves are half grown.