Sycamore Tree Anthracnose - are injections worth the money?

Asked July 31, 2013, 7:57 AM EDT

Hello,
I have a large and beautiful Sycamore tree providing wonderful shade to my back yard patio. However it is severely infected with Anthracnose and drops it leaves, twigs etc. every year, making an unpleasant environment. Local arborists are recommending expensive injections of fungicide to help control this. Do you have any information on the probability that these will be helpful? It would be useful to know this prior to spending the money.

Lake County Illinois

1 Response

I am not sure if you’ve tried other measures to control the anthracnose infection of your sycamore tree before you consulted the arborists. The jury does seem to be out on the effectiveness of the use of fungicides to control this disease. Anthracnose rarely causes significant damage to trees, so usually specific control measures are not required. Nevertheless, anthracnose can increase susceptibility to other diseases or insect problems in areas where trees are attacked year after year.

First, let’s look at cultural practices that can reduce the severity of anthracnose and minimize its impact on tree health, especially if you have not implemented these measures. Also, if you still decide to have the fungicide injections, the addition of these practices may give you a better outcome. Stressed trees are more susceptible to the disease. Reduction of stress can encourage vigorous plant growth and aid in tolerance of the effects of disease and in rapid refoliation. Unfortunately, there is no single approach to the management of anthracnose that will give consistent, acceptable control of the disease.
1)
Clean up and destroy as many of the fallen leaves as possible, especially in the fall. This will help reduce the overwintering population of anthracnose fungi and limit the amount of fungal inoculum present for infection of new leaves the following spring.
2) Prune the tree to remove diseased twigs and branches and to open up the canopy for better air circulation and light penetration. Be sure to make proper pruning cuts.
3)
Fertilize in the fall about a month after the average date of the first frost or in early spring about a month before the date of the last frost to increase tree vigor

4) Maintain a proper and consistent watering schedule.
5)
Avoid damage to the tree bark by lawn-mowing equipment.


Hindsight may be 20-20, but here are two additional suggestions for future tree selections:
1)
Proper tree spacing and placement to promote good air circulation reduces the number of hours leaf surfaces remain wet, and decreases the likelihood of fungal infection.

2)
Use less susceptible varieties of trees, especially in areas with poor air circulation.


So now, let’s move on to a discussion of fungicide use. Research and experience show that fungicide control of anthracnose is rarely warranted because anthracnose usually does not seriously damage tree health. In addition, injections of fungicides into the tree have given erratic and unsatisfactory control of the disease. Occasionally, trees with a history of severe anthracnose may show aesthetic benefits from treatment. If fungicides are used, always utilize the services of trained arborists or other tree-care professionals. Also, proper treatment timing is essential for adequate control