Anthracnose (fungus)	Small, scattered brown spots along veins, giving leaves a scorched appearance. Occassionally, the fungus blights the leaf and causes the margins to crinkle and curl. (Can be confused with nonparasitic leaf scorch.)	Collect fallen leaves. In wet years it may be necessary to use a fungicide at time of early leaf break and twice thereafter at 10- day intervals. Use azoxystrobin, chlorothalonil, chlorothalonil + fenarimol, copper products, mancozeb, maneb, myclobutanil, propiconazole, sulfur, thiophanate-methyl or triadimefon. Azoxystrobin, chlorothalonil and chlorothalonil plus fenarimol may be used on the red oak group only.
Bacterial leaf scorch (bacterium)
	Leaf margins scorch, often beginning in early summer, but typically occur late in the season. Usually first appears on upper and outer branches, becoming more severe each year over several years. Appears first on oldest leaves of a shoot. Affected leaves usually retained until fall. Sapwood never streaked as with oak wilt. Bacterium spread by leafhoppers. Little is known about the distribution of this disease in Missouri, although 7 samples were positive for bacterial leaf scorch during 2000.	Laboratory tests are needed for postive diagnosis. Submit fresh, symptomatic leaf tissue in late summer or early fall before fall leaf drop to the Extension Diagnostic Clinic. Prune out infected branches to prevent further spead in the tree. Fertilizing and irrigating may prolong the life of dieased trees, although the trees may be removed to prevent spread to other nearby healthy trees. Control of insect vectors has not been shown to be effective in curbing the spread of this disease.
Dieback and decline (disease insect environmental complex) (see MU publication G 5200)	Caused by a combination of environmental stress factors. Symptoms include early fall coloration, late spring growth flush, sparse foliage with small leaves and branch dieback.	See the Plant Disease Profile on "Dieback and Decline of Shade Trees and Shrubs". To prevent decline, avoid soil disturbance around root zones, maintain soil pH as slightly acidic, avoid injury and water dur ing periods of moisture stress. Routine maintenance to promote vigor.
Iron chlorosis (nonparasitic)
	Iron deficiency. Some oaks (especially pin oak) are susceptible in neutral or alkaline soils. Yellowish-green leaves with darker-green veins.	Usually, iron deficiency is due to lower availability of iron under alkaline conditions, rather than a lack of iron in the soil. For long-term control, the best approach is to acidify the soil. Temporary control can be achieved by applying iron chelate to leaves or soil, or iron sulfate to expanding leaves. Acidify soil with ammonium sulfate or sulfur.
Leaf galls (insects and mites)	There are many types of galls that commonly occur on oak leaves.	Leaf galls do not affect tree vigor and should be ignored. Also see MU publication G 7272.
Oak wilt (fungus)
	Leaves in the upper crown become dull green, bronzed or scorched. Defoliation begins soon after symptoms appear. Green leaves also may drop. Brown to black streaks develop in sapwood, but they may be difficult to detect. Positive identification possible only by laboratory culture.	In the red oak group, disease is almost always lethal. Species in the white oak group are somewhat resistant and sometimes recover on their own. Avoid injuring health trees. Do not prune oaks from April 1 to July 1 because wounds attract insect vectors. Sever root grafts to uninfected oaks mechanically (vibratory plow) or chemically (metam sodium (sold as Vapam)). After root grafts with like species have been broken, remove infected trees promptly. Do not move or store wood from infected trees without debarking, chipping or drying it. Chemical control using fungicides (propiconizole (Alamo) is labeled) injected into oaks not yet showing symptoms is another option. This procedure is expensive, requires a trained professional to administer and multiple applications are necessary. Therapeutic use in symptomatic trees is unsuccessful.
Powdery mildew (fungus)	Whitish, powdery mold on underside of leaves. Rarely, upper surface may be affected and leaves may be stunted, distorted and drop early.	Collect and remove fallen leaves. If contol is necessary, when mildew appears, apply lime sulfur, myclobutanil or tridimefon.
Taphrina leaf blister (fungus)	Yellow or brown and more or less round, raised blisters on upper leaf surface.	Control normally not recommended for shade trees. This is mainly an aesthetic problem and will not harm vigorously growing trees. Refer to the PDC Fact Sheet "Leaf Spot Diseases of Shade Trees and Ornamentals" for more information. If fungicides are deemed necessary for aesthetic reasons, apply fungicide just before leaves open. Use chlorothalonil, fixed coppers, lime sulfur, mancozeb or maneb. Chlorothalonil may be used only on oaks in the red oak group.
Tubakia (Actinopelte) leaf spot (fungus)	Small reddish-brown, pinhead-sized spots. When infection is severe, leaves may scorch. Symptoms may be more severe on trees with iron chlorosis.	Refer to the PDC Fact Sheet "Leaf Spot Diseases of Shade Trees and Ornamentals" for more information. Usually, symptoms develop too late in season to warrant control.
Twig galls (insects)	Gouty and horned oak galls are common on oaks in Missouri. Infestations are commonly observed on shingle oak.	Although these are ugly and somewhat damaging to the tree, there is little that can be done except to prune out and destroy the galled branches before the insects emerge. MU publication G 7272.
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