Dothiorella canker
Neofusicoccum spp.
What are Branch canker and dieback (Neofusicoccum ssp.)?
Branch canker and dieback, formerly known as Dothiorella Canker, is a fungal disease caused by Neofusicoccum, Botryosphaeria, and Fusicoccum species. It affects a wide range of woody plants worldwide, including avocados, apples, pears, peaches, and ornamental trees. Symptoms include elongated dark discolorations, cracked or sunken bark, and reddish sap that dries to brown and white powder. Leaves and small branches may wither and die, while infected fruit develop small brown lesions that become sunken and black, leading to subsequent decay.
How do Branch canker and dieback (Neofusicoccum ssp.) occur?
Neofusicoccum fungi enter plants through wounds or natural openings. They colonize the bark, causing sunken cankers that encircle stems and branches, leading to dieback of leaves and fruit. The disease spreads in wet conditions like rain or irrigation. Infected plant material can also transmit the disease. Warm and humid conditions, with temperatures between 20°C to 30°C (68°F to 86°F) and high humidity, favor the development of this disease.
Symptoms
1 - Effect on Plants
Fungal presence leads to stem and branch dieback, early leaf shedding, and fruit decay. It diminishes productivity and quality in fruit trees and grapevines, and weakens plants, making them more vulnerable to diseases and stresses.
3 - Effect on Soil
Decaying infected plants release nutrients and organic matter, fostering fungal growth and infection. Accumulation of dead plant material can cause soil compaction and decreased water infiltration.
Solutions
1 - Cultural Control Measures
• Proper irrigation techniques, reducing plant stress, planting high-quality material, and maintaining good tree nutrition can prevent plant stress and infection. • Avoid excessive use of nitrogen fertilizers, which can promote disease development.
2 - Physical Control Measures
• Infected plant material should be removed and destroyed, and pruning wounds should be avoided or minimized. • Clean pruning tools can prevent the spreading of the pathogen.
3 - Chemical Control Measures
• Fungicides commonly used for this fungus include Boscalid, copper-based fungicides, Fludioxonil, Propiconazole, Pyraclostrobin + boscalid, and Thiophanate-methyl. But their use should be determined by a professional. • Fungicides with different modes of action should be rotated to prevent resistance. • Fungicides should only be used to supplement cultural and physical control measures.
