To whom it may concern, I was wondering if you could tell me more about 2...

Asked September 3, 2013, 3:46 PM EDT

To whom it may concern, I was wondering if you could tell me more about 2 trees I have in my yard. The first is an oak tree with brown spots, the second is a tulip poplar tree with a soft, black area at the trunk base. Any information would be greatly advised. Sincerely, Jon Mesarch

Hocking County Ohio

1 Response

Oak Tree I’m assuming the brown spots on the leaves of the oak tree. (If it is on the bark, please let me know).

Below is information from the Iowa State University on oak trees with leaf damage:
Concerns about oak trees have been common this spring. Careful observers have noticed that some of the leaves on oak trees appear more brown than green, especially the leaves on the lower branches. Some of these leaves have even curled and fallen to the ground. The question on everyone’s mind is “Is this a serious condition or something superficial?”

Anthracnose
has been a widespread disease on oak trees this season. Spring conditions that are cool and wet favor the development of anthracnose diseases. Although the common name of the disease sounds quite alarming, it is actually a fairly minor problem on established oak trees.
Anthracnose is a fancy term for a leaf spot or leaf blight disease. Caused by a fungus, typical symptoms appear as papery brown spots on leaves, often associated with the leaf veins. These spots can coalesce, causing large areas of browning on the leaves. The leaves appear as if they have been scorched. With time, diseased leaves may curl and drop from the tree.

Anthracnose diseases are caused by a number of different but closely related fungi. Each fungus is specific to the host tree if affects. For example, the fungus that causes anthracnose on oak does not infect ash or maple trees.

The warm and dry conditions of summer are not favorable for most anthracnose fungi, and trees tend to put out additional leaves that appear healthy. The fungi that cause leaf diseases of trees may survive on fallen leaves, so raking and removing fallen leaves can be helpful in reducing the disease. Fungicides sprays for control of leaf diseases are typically not warranted on established shade trees. Fungicides cannot be used to “cure” infections once they have already occurred.

Good cultural practices that promote tree vigor can help trees recover from disease problems. Young trees should be properly pruned to promote good branch structure and good air circulation. To reduce the risk of oak wilt infection, remember to prune oak trees only during the dormant season. Mulching with an organic mulch such as wood chips and watering during drought spells help to promote a healthy root system.


Oak wilt
causes loss of leaves and death of branches. Anthracnose, on the other hand, can cause defoliation, but new leaves typically emerge as time progresses. Anthracnose is most commonly observed on lower branches in the spring, especially if extended wet conditions occur, whereas oak wilt symptoms may appear throughout the tree. Symptoms of leaf loss and branch death related to oak wilt are most often observed as conditions become hot during the late spring and summer months. In contrast, the seriousness of anthracnose tends to lessen as the summer progresses.


Diagnosing oak wilt can be difficult. Other factors, such as construction injury, drought stress, advanced tree age and borer activity can contribute to dieback of branches and can be confused for diseases caused by fungi. A close look at a sample in a laboratory can be helpful. Anthracnose can be diagnosed by using a microscope to look for specific fungal structures on the underside of leaf tissue. Oak wilt is diagnosed by culturing branch segments from affected areas in the trees.


Samples of diseased oaks can be submitted to Michigan State for diagnosis. Below is the link:
http://www.pestid.msu.edu/

Below are links to detailed information on oak tree problems:

http://www.caes.uga.edu/publications/pubDetail.cfm?pk_id=7387 http://extension.psu.edu/pests/plant-diseases/all-fact-sheets/oak-diseases

Tulip Poplar Tree

Poplar trees are soft wood – was the tree subjected to any storm or other damage? I believe the condition will improve. I would monitor the problem and maintain regular maintenance, including fertilizer. Please send another question in the near future if there is growth in the soft area.

Please let me know if you have any additional questions.

Thank you,
Mary C.