July 21, 1995

Cherry Leaf Spot

Cherry leaf spot is caused by the fungus Coccomyces hiemalis. The disease first appears on the upper side of leaves as small, circular, purplish spots. Later, these spots turn brown and the tissue falls, leaving a circular hole in the leaf. Because of this symptom, the disease is sometimes referred to as "shot-hole" disease.

Infected leaves eventually turn yellow and fall from the tree. Only a few lesions per leaf can cause yellowing and leaf drop. When the disease is severe, fruit, stems, and leaf petioles may also be infected by the fungus.

Ten Rules of Edible Flowers

The culinary use of flowers dates back thousands of years to the Chinese, Greek and Romans. Today there is a resurgence of interest in edible flowers. Are all flowers that aren't poisonous edible? Definitely not. Listed below are a few simple rules to follow before sampling flowers.

Watch for Japanese Beetles in Iowa

The Japanese beetle has been one of the most troublesome urban insect pests in the eastern U.S. since it was imported into New Jersey with ornamental plants from Japan about 1916. It has spread on its own and with nursery stock and sod throughout the eastern half of the U.S.

Septoria Leaf Spot on Dogwood

Dogwoods are susceptible to a number of fungal leaf spot diseases. Red and yellow twigged dogwoods are particularly susceptible. Most of the dogwood samples arriving in the Plant Disease Clinic have been showing Septoria leaf spot. This disease typically causes angular, grayish spots with a dark purple or reddish border. Symptoms usually occur first on lower leaves. As with many of the fungal leaf spot diseases, wet spring weather favors their development.

Weather-Related Garden Problems

Weather conditions greatly affect the growth and yield of vegetable crops. Wet, cool weather often leads to disease problems. Unfavorable weather can also cause physiological disorders or problems. Common non-infectious, weather-related problems that occur in the vegetable garden include:

Blossom Drop --- Plants fail to set fruit.