- Root rot is a fairly common problem in the gardening world. It is the result of bacterial infection and is most common during periods of excessive rain or flooding. These wet conditions are ideal for bacterial growth, which eventually will enter the plant through the roots. The infection will turn the roots into a useless gray mush, making them unable to transmit water and nutrients to the plant. Yellow or brown leaves, stunted growth, and overall health decline are early symptoms of root rot. Generally, by the time symptoms occur it is too late to save the plant. To combat the problem, growers should make sure soil drains well and eliminate dead or fallen debris from the base of the plant.
- Chestnut blight first reached the United States in the early 1900s and is a result of the endothis parasitica fungus. It primarily is a concern of older trees and will frequently cause death if left untreated. The fungus most often is introduced through wounds or cracks in the bark that occur with age. This results in cankers on the branches and stems of the tree. Chestnut blight cankers will spread quickly and cause yellowing of foliage, wilting and eventually death. Mudpacks made with pesticide treated soil are an ideal treatment for the disease, though several treatments may be required for large infections.
- Dutch elm disease came to the United States in the early 1930s, and during the decade it did major damage to a number of plant species. The disease is an infection caused by the Ophiostoma ulmi fungus. which infects vascular tissue and greatly reduces or stops water from reaching the upper part of the tree. As the infection grows, the tree will wilt and die. Growers watch for leaf yellowing and "flagging," a yellowing that starts at the edge of the branch and progresses inward and down toward the roots. Infected branches will have a characteristic streaking that runs just below the outer bark. The key to managing the disease is controlling the spread by ridding the area of the elm bark beetle, a major transmitter of the disease, using pesticide. Additionally, cleaning up debris and fallen limbs will limit bug populations, preventing spread of the disease. Early treatments with fungicides also are effective at eliminating established colonies.
- White pine blister rust affects the pinus genus throughout Canada and the United States. The Cronartium ribicola fugi infects the trees through openings in the needles. Growers should be especially diligent during seasons of extended cool, damp weather, particularly during the late summer and into early fall. The fungi most frequently will start from the bottom and work its way up the tree. To reduce risk of infection and prevent bacterial growth, growers should promptly remove and destroy any fallen needles and debris. The bacterium causes the growth of yellow or red spots along the bark and branches. It often is fatal to trees. There are a number of management techniques that growers may try, though none are 100 percent effective. Quarantining affected plants is important, as are appropriate clean up and pruning.
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