Many species of ornamental trees and shrubs are susceptible to Phytophthora root rot, especially if the soil is saturated for a long period of time. The typical symptoms of root diseases can be noticed in infected plants. The leaves will dry out and appear stressed. They can die quickly when the environment becomes warm during late spring or early summer. The dogwood an the oak tree are examples of trees that are vulnerable to this kind of disease.
Symptoms and Diagnosis
Leaves will appear dried up and stressed. Sometimes, they will turn red, purple, or light green as they wither. The bark in contact with the top soil can appear darkened. Trees that are infected may survive several years before they die. If you cut some of the bark, you can see red-brown discoloration in the revealed wood.
Species of Phytophthora that cause root-rot could survive in the soil for many years, as long as it is moist. They can spread through runoff water, irrigation water, and runoff water. Disease fungi can spread through contaminated garden tools and equipment and soil. Rot is likely to spread during early spring or late fall when there is a little rain and the temperature gets cooler. However, most symptoms are common during low rainfall when stress level is high. Root rot can easily spread when the soil is inundated for six to eight hours. Trees and plants without wounds can still be infected.
1. Improve water drainage. Before planting, make adjustments to the composition of the soil. This will help regulate drainage and avoid rotting. Don’t let water gather around your plant’s base. Aerate to improve drainage and minimize compaction.
2. Raise your planting site. This is a great way to avoid poor drainage and keep water from pooling around the base of your plants or trees. Remember, it’s not ideal to plant trees deeper than they were originally planted at the nursery.
3. Separate plants, trees, and shrubs according to their irrigation needs. And do not overwater.
4. Remove soil. If the soil is piled up over the crown, carefully remove it to reveal the root flare. This is where fungal infection usually occurs.
5. Plant resistant or less vulnerable varieties. When you’ve found out that your plants have been infected by the Phytophthora root rot, consider replanting more resistant plants. The American arborvitae an the white cedar are examples of tree species that are highly resistant to Phytophthora root rot.