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Symptoms of "tatters" have been seen on white and bur oaks in southern Wisconsin since the early 1990s.

This branch shows tattered foliage and new, uninjured foliage.

adult beetle
Symptoms on bur oak associated with oak tatters. Note the absence of tissue between the veins.

An oak with a minor anthracnose infection.

What to look for

Symptoms appear in mid to late May and they may be seen in oak woodlands or on single yard trees. Red and black oaks typically do not show symptoms. Tattered trees have thinner leaves than usual and may look like they don't have any leaves from a distance.

If tatters affects most of the leaves on a tree, the tree will grow new leaves to replace them about two to three weeks following the appearance of tatters. Although growing a new set of leaves can stress a tree because of the extra energy it uses, spring is the best time for this to happen because the tree has the rest of the growing season to refill its energy supply.

Preventing and managing tatters

Recent research claims herbicide drift from row crop agriculture may cause leaf tatters on oaks. Previously, people thought that cold temperatures during the times when buds open and leaves grow were followed by the appearance of tatters.

Other diseases and insects--such as anthracnose and cynipid wasps--can cause damage that may be mistaken for tatters. A cynipid wasp forms galls that deform leaves and new growth. Current year’s galls are green; one-year-old galls are black. Cynipid wasps are most commonly seen infesting white oak. Severe damage is rare but there is no known treatment.

Anthracnose, a disease caused by a fungus (Discula quercina), may infect leaves and cause brown to black spots on leaf edges and along leaf veins, especially in the lower canopy. Anthracnose may cause some twigs to die and is most common during cool, wet springs. Significant injury is rare. Rake and dispose of infected leaves to minimize spread.

Last revised: Monday August 03 2015