SAN JOAQUIN COUNTY, CA- Like people, plants need a healthy environment.
To reduce our chances of becoming ill, we get plenty of fresh air and clean our homes to remove bugs and bacteria. Yet we neglect our plants by leaving fruit, fallen leaves, weeds, dead branches, even dead plants in our gardens!
Fruit and fallen leaves are ideal locations for pests and diseases to harbor. Weeds and dense vegetation under trees and shrubs provide hiding places for pests and reduce airflow, increasing humidity and the likelihood of fungal diseases. Good sanitation is important for optimum plant health. Our summer fruit and vegetable crops are starting to dwindle. You may notice an abundance of fallen fruit and leaves under your trees. One question we often receive in our office is whether you should leave the fruit to compost or clean it up. Sanitation is necessary to prevent disease and pests and reduce the needs for sprays.
Often times fruit left on or around the tree will not rot completely. These fruit will shrivel up into a small ball and are called mummies. Although they may look dry and harmless these mummies will produce fungal spores during the spring and summer that can infect new fruit. Brown rot on peaches and summer rots on apples can quickly spread and may be uncontrollable, even with fungicide applications.
What you can do
Here are a few simple steps to help reduce both the severity of infections and continuing infestation by pests and diseases.
• Remove damaged and diseased branches.
• Prune plants for better air circulation. For dense plants or plants with persistent foliar fungal diseases, winter is a good time to do some thinning.
• Keep areas under trees clean. Keep the stem free of piled mulch, weeds or other competing plants. Keep weeds and grass cut short under the tree canopy.
• Remove dead plants as soon as possible. A dead plant provides a home for insects that may spread diseases to other plants.
• Rake leaves after they drop and before the first rains arrive. Because of the high rate of infection in leaves of fruit trees, ornamental cherries, ornamental plums and dogwoods, we do not recommend composting these leaves. Put them in yard waste bins for pickup. The leaves of most other plants make good additions to your compost.
Fruit trees Several additional steps are necessary to reduce disease and pest problems in fruit trees.
• Remove diseased flowers that remain on the tree after fruit set.
• Remove early fallen fruit and thin remaining fruit if necessary. Dispose of fruit.
• After harvest, remove and destroy overwintering fruit (mummies) in the tree and on the ground to eliminate sources of disease and insects next season.
If you have any questions about sanitation, fruit tree management or whether your leaves are suitable for compost, call the UC Master Gardeners at (209) 953-6112 or visit our web-site at http://sjmastergardeners.ucdavis.edu.