Lichen diseases of apple trees: description with photographs
Representatives of the genera Cladonia, Hypogymnia, Parmelia Dicranum, Mnium , etc. are common among mosses
The description of these diseases of apple trees should begin with the fact that they develop when plantings are dense, poor ventilation, poor lighting of the bushes, and conditions of high humidity are created. Such conditions are very favorable for the development of lichens and mosses, pathogenic microorganisms that cause bark necrosis, stem and root rot. Any plant covered with lichens has a sparse crown and weak growth of shoots; lichens from one tree or shrub quickly spread to neighboring ones.
The thalli of lichens retain moisture on the surface of the bark, which can cause the formation of frost holes in severe winters, and many insect pests constantly overwinter under the thalli. The spread of lichens and mosses indicates, first of all, the weakening of plants.
Seeing a description of the apple tree disease with photographs, you can arm yourself with knowledge about the potential danger and begin to fight it as recommended below.
Control measures. Constant cleaning and removal of thalli from trunks and skeletal branches and spraying plants in the fall with a solution of iron sulfate (300 g/10 l of water).
Look at the lichen diseases of apple trees in the photographs, which show the most typical symptoms:
Powdery mildew
Apple tree diseases are common and rare. Powdery mildew is one of the most common problems with this tree. It affects leaves, buds, young and mature shoots, and inflorescences. The main symptom is a white coating, which is quite easily erased. After a while it becomes brown and forms a thick crust.
Apple powdery mildew
To combat it, the tree is sprayed with the preparation “Skor” or “Topaz”, “Fundazol”, “Tilt”, “Raek”, “Zato”. They all work well. At an early stage, colloidal sulfur (80 g of sulfur per bucket of water) is also suitable. After the tree has finished flowering, it is sprayed with copper oxychloride. After harvesting, treatment is done with copper sulfate. As a preventive measure, it is necessary to prune the tree annually, remove excess timber, and then burn it outside the site.
Diseases of the bark and trunk of apple trees and their treatment (with photographs)
The main diseases of the bark and trunk of apple trees are caused by fungi and are combined into a group called cancer. Further in the material, these apple tree bark diseases and their treatment are discussed with a description of the characteristic symptoms.
Common or European apple tree cancer .
The causative agent is the fungus Neonectria galligena (Bres.) Rossman & Samuels (syn. Nectria galligena Bres.). Elongated brown spots appear on the bark, which dry out and crack. Beneath them, ulcers with raised edges of callus tissue are exposed. Over the years, the ulcers increase in size and depth, and the wood gradually dies. When young plants are damaged, death occurs after 2-3 years.
On the trunks an open form of cancer is detected in the form of deep ulcers, on the branches there is often a closed form, in which the nodules grow together and a gap remains. When the disease manifests itself on a massive scale, deep ulcers also form on the skeletal branches. In the affected wood, sporulation develops along the edges of the canker in the form of whitish-cream pads that dry out and darken over time. The spores recharge neighboring branches and leaves.
Affected leaves become chlorotic, necrotic brown spots without borders appear on them, the leaves gradually dry out and fall off prematurely. Brown spots appear on the fruit on the stem side, which lead to rapid rotting. The infection persists in the affected wood and plant debris.
The disease is widespread on almost all fruit and berry crops, ornamental and deciduous tree species. With dense plantings, constant re-infection of plants is possible. The disease most often manifests itself on weakened planting material and in places of frost damage and mechanical damage to the bark of trunks and branches.
Control measures. Use healthy planting material without any necrosis of the bark and ulcers on the shoots. Compliance with all agrotechnical requirements for growing this crop. Timely pruning of affected branches with cankers and burning them. Individual ulcers in the forks of skeletal branches are disinfected with a 1% solution of copper sulfate and covered with oil paint on natural drying oil. Annual preventive spraying of plant bark before leaves bloom with Bordeaux mixture or its substitutes (HOM, Abiga-Peak).
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