Gumosis is the leakage of sap from wounds or cankers on fruit trees. Gumosis can result from environmental stress, mechanical injury, disease, or insect infestation. Cytospora canker or Valsa canker, the fungal cause of gummosis, affects stone fruit trees such as apricot, cherry, peach and plum. Cytospora infection is distinguished from insect damage and mechanical injury because sawdust or pieces of bark are not mixed with the sap as they would be in insect damage or mechanical injury. Cytospora cancer is also known as permanent cancer.
Symptoms and Diagnosis:
In trees infected with cytospore canker, new shoots or leaves may turn yellow or wilt. Sunken lesions develop on the bark. These lesions enlarge and gummy, amber-colored sap oozes from the rind. Curly orange threads (mushroom chains) may emerge from the bark as the disease progresses. Leaves may turn brown and fall off. The disease kills the wood beneath the crabs, often resulting in the death of entire branches. Infected wood and the defoliation that may occur will weaken the tree, but if the disease affects the trunk, the entire tree can die.
Life cycle :
Cytospora cancer is caused by two different fungi. The fungus overwinters on dead wood or in sunken wounds. Orange strings of mushrooms release spores in spring that are spread by wind and spray. Once the spores land on a host tree, they enter through insect wounds, mechanical injury, or winter damage. Symptoms are more common in warm (70-85 degrees F) and humid spring weather because moisture makes it easier to penetrate wounds. Trees coming out of dormancy are most susceptible to this pathogen.
Since the main culprit of Gummoss, Apricot, Peach, and Plum attacks weakened trees, do your best to keep yours healthy through mulching, watering, and optimal nutrition. You should fertilize with nitrogen in late winter or early spring. This will prevent your tree from producing growth that could be damaged by cold weather in the fall.
Precise trimming and removing damaged tissue:
Be very careful when pruning. Make proper cuts and don’t trim in wet weather. It is important not to leave stumps or shallow cuts, and not to make flush cuts. Remove infected branches and twigs by carefully pruning back to healthy wood. If possible, do this in dry weather, in summer, so that the wound heals as quickly as possible. Sterilize your tools between cuts with Lysol wipes or 10% bleach. It may not be possible to curtail all of the damage once the fungus has spread.
Use professional tree care services:
Sometimes treating your orchard to prevent and cure disease can be overwhelming. Professional citrus care and maintenance services can help protect your orchard from potential diseases and other risks. Tree care services include how to get your citrus trees the proper nutrition, watering and treatment needed to control Phytophthora gum and other diseases that could be damaging your orchard. A certified arborist will help you keep your grove of trees happy and healthy year-round. Whether you want to prevent Phytophthora gummosis or other diseases, has the experience you need to protect your trees.
Protect from sunstroke:
Protect the bark of your tree from sunstroke in winter. You have two options for this. The first is to paint the trunk with half white latex paint and half water. A human hand applies diluted latex paint to the trunk of a fruit tree with a brush. The other solution is to apply white foil to the trunk from December to March.
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