Canker diseases
Botryosphaeria Cytospora
What is Canker disease (Botryosphaeria, Cytospora)?
Canker diseases caused by Botryosphaeria and Cytospora fungi impact various woody plants worldwide. They infect ornamentals, fruit trees (e.g., pistachio, avocado, grape, apple), and conifers like pine and spruce. Symptoms of these canker diseases include the formation of cankers, yellowing, and wilting of leaves, excessive leaf drop, branch dieback, resin or sap exudation, and the presence of black fruiting bodies. The diseases result in the loss of branches, disfigurement, reduced fruit production, and increased fire risk.
How does Canker disease (Botryosphaeria, Cytospora) occur?
Canker disease occurs when these pathogens infect stressed plants through wounds, insect feeding, or environmental factors. The fungi grow within the plant, causing cankers and disrupting water flow. They reproduce through both sexual and asexual phases, forming fruiting bodies that release spores. These spores can be spread by wind, rain, or birds to new branches or susceptible hosts. The fungi can survive in cankers and plant debris for several years, germinating when favorable conditions like warm and wet weather occur, leading to new infections.
Symptoms
1 - Impacts on Plants
Canker diseases weaken plants, causing reduced vigor, branch dieback, and decreased fruit production.
2 - Impacts on Soil and the Environment
• Infected branches release nutrients into the soil, affecting nutrient cycling and microbial interactions. • Canopy thinning from branch loss increases fire risk and disrupts habitats for wildlife. • Invasive canker pathogens pose a threat to native plant communities, impacting biodiversity.
Solutions
1 - Cultural Control
• Choose plant varieties suited to the site conditions. • Provide adequate water, nutrients and avoid drought stress. • Prune and dispose of infected branches. • Use mulch to retain soil moisture. • Ensure proper light conditions for plants.
2 - Mechanical Control
• Prune infected branches, cutting a few inches below the canker. • Use sanitized pruning tools to prevent pathogen spread. • Disinfect tools if the discoloration is present. • Consider removing severely infected plants.
3 - Chemical Control
• Fungicides with phosphorous acid including Agri-Fos can protect foliage and prevent new canker formation. • Fungicides may not cure existing infections but can limit further spread. • Check for available fungicide products specific to the disease.
