|Leaf spot||Irregular, reddish-brown spots on the upper leaf surface form while brown spots occur on the lower leaf surface. In severe cases, leaves may fall prematurely.||Gnomonia caryae||No control is recommended since the disease occurs late in the season and little damage results. However, raking and destroying leaves in the fall can reduce the amount of inoculum near the trees.|
|Microstoma, downy, or white leaf spot||Pale yellow spots of various sizes are observed on the upper side of the leaf. The lower side of the leaf spot appears white or powdery. In severe cases, a witches’-brooming occurs on branch tips (= large numbers of twigs).||Microstoma juglandis||No control is recommended. White, bur, shingle, overcup or post oaks are also susceptible.|
Microstoma, downy, or white leaf spot.
Notice: The user of this information assumes all risks for personal injury or property damage.
Warning! Pesticides are poisonous. Read and follow all directions and safety precautions on labels. Handle carefully and store in original labeled containers out of the reach of children, pets, and livestock. Dispose of empty containers right away, in a safe manner and place. Do not contaminate forage, streams or ponds.
Issued in furtherance of Cooperative Extension work, Acts of Congress, May 8 and June 30, 1914, in cooperation with the U. S. Department of Penn State College of Agricultural Sciences research and extension programs are funded in part by Pennsylvania counties, the Commonwealth of Pennsylvania, and the U.S. Department of Agriculture.
Visit Penn State Extension on the web at extension.psu.edu.
Where trade names appear, no discrimination is intended, and no endorsement by Penn State Cooperative Extension is implied.
This publication is available in alternative media on request.
The Pennsylvania State University is committed to the policy that all persons shall have equal access to programs, facilities, admission, and employment without regard to personal characteristics not related to ability, performance, or qualifications as determined by University policy or by state or federal authorities. It is the policy of the University to maintain an academic and work environment free of discrimination, including harassment. The Pennsylvania State University prohibits discrimination and harassment against any person because of age, ancestry, color, disability or handicap, national origin, race, religious creed, sex, sexual orientation, gender identity, or veteran status. Discrimination or harassment against faculty, staff, or students will not be tolerated at The Pennsylvania State University. Direct all inquiries regarding the nondiscrimination policy to the Affirmative Action Director, The Pennsylvania State University, 328 Boucke Building, University Park, PA 16802-5901; Tel 814-865-4700/V, 814-863-1150/TTY.