Common Tree and Shrub Diseases in Michigan
Fungicide applications are needed for disease activity during wet seasons. Multiple foliar sprays and/or trunk injections are preventive and need to be timed properly for effective control.
Identifying and foliar spray treatments will target this disease to minimize fungal activity. Prune out infected twigs to reduce the spread of anthracnose. Keeping trees in good vigor with deep watering during droughts, nutrition with fertilization and control of insects can help decrease susceptibility to the disease.
Diplodia Tip Blight
Keeping trees in good vigor with deep watering during droughts, nutrition with fertilization and control of insects can help decrease susceptibility to the disease. Fungicide control is most effective in early spring.
Dothistroma Needle Blight
Early identification of Dothistroma Needle Blight can prevent major damage to individual trees and prevent the spread to nearby trees. Protecting new growth as it emerges is very important.
1) Treat high value asymptomatic oaks that are within root-grafting distance of infected white oaks. Preventative systemic treatment and early detection are vital to saving our oak trees.
2) Never prune oak trees from April through June. Delay pruning until dormant season to further minimize contamination risk.
Preventative fungicide applications are helpful in controlling symptoms. Proper timing, before symptoms appear, is crucial to getting good control. Good cultural control includes: spacing plants appropriately, pruning for air flow, removing dead plant material and not watering from overhead.
Soil fertilization treatments produce the best results. Iron and manganese replacement address the root of this disease.