Fungal Diseases in the Orchard
Almond trees are at risk to several fungal diseases in the orchard. Hull rot, shot hole, brown rot, almond scab, Alternaria leaf spot, leaf rust, and anthracnose are just some of the diseases caused by fungi.
As with all diseases in almonds, fungal disease prevention begins with selecting disease-resistant varieties and rootstocks before planting, and planting in areas without previous almond disease problems.
Most critical to infection and disease are:
- Environmental parameters – wetness periods, temperature, relative humidity
- Open wounds – mechanical shakers, crown gall infections
- Stage of plant growth – bloom to newly split hulls
Disease management strategies include:
- Avoid planting in low areas, or areas with a history of standing water
- Develop an irrigation system that is designed not to wet tree leaves
- Avoid prolonged irrigation sets that lead to standing water
- Manage a nitrogen fertilization program to avoid excessive nitrogen, which can promote some major almond diseases
- Use management techniques and cultural practices that promote strong, healthy trees that can resist diseases
- Avoid transfer of disease organisms from one area to another via equipment and/or personnel
- Manage the tree canopy for good air circulation
Losses from these diseases are not only reflected in reduction of crop, but in branch death and tree decline, as well as death of young and mature trees.
Monitor trees and environmental conditions for disease risk, and use monitoring techniques to time control operations. Coordinate disease management activities with cultural operations, and manage the program to optimize crop protection while minimizing human and environmental risks.
When treatment is necessary for diseases, keep in mind resistance management practices in your IPM program as discussed in the Diseases section.
Guidelines for Almond Scab Management
In collaboration with Western Farm Press magazine, The Almond Board of California created an e-learning course on disease management in almonds
UC IPM Almond Fungicide Resistance Management
UC IPM Pest Management Guidelines
Seasonal Guide to Environmentally Responsible Pest Management Practices in Almonds