Plant Diseases

Learn about one of the major diseases associated with poor water management, Phytophthora root and crown rot.

A well-watered plant that suddenly wilts or unexpectedly drops its leaves could be infected with the soil pathogen Phytophthora. The disease it causes, Phytophthora root and crown rot, can affect many plants, including ornamental trees and shrubs, fruit trees, and vegetables.

While you may not notice symptoms of peach leaf curl until the spring, you should manage it in the fall and winter. Peach leaf curl is a fungal disease that primarily affects peach and nectarine trees.

After years of drought, we welcome rain in California. But we also recognize that rain can help spread a number of plant diseases. Rain and wind can splash bacteria and fungi from infected leaves, branches, and blossoms to uninfected parts of the tree.

Spring is just around the corner and many types of fruit trees are starting to develop their leaves. If you are growing peaches or nectarines and are now seeing symptoms of peach leaf curl on new leaves, unfortunately it's too late to manage the disease.

Springtime planting is almost here but don't rush to plant seeds until the soil has warmed up! Planting seeds too soon, when the soil is cold and wet, risks losing them to damping-off, a disease caused by fungi and oomycetes in the soil.

Healthy Soils Week (Dec. 4-8) is a week-long initiative by the California Department of Food and Agriculture (CDFA) to highlight the importance of soil health throughout California. Healthy soils can improve crop yields, sequester carbon, reduce erosion, and increase biodiversity.

Peach leaf curl is a fungal disease that only affects peach and nectarine trees. The fungus causes distorted, reddened leaves to appear on the tree in the spring.

Sudden oak death (SOD) is a disease syndrome that has killed millions of native oak trees (Figure 1) along the west coast of the United States, from Big Sur in California up to Southern Oregon.