The cherry It is a kind of fruit that belongs to the Rosaceae family and the stone fruit subgroup. Its cultivation can be done organically, but to obtain a satisfactory harvest of cherries in terms of quality and quantity, it is important work hard to prevent the adversities.
Unfortunately it is a rather delicate species and it is necessary to constantly observe the plants to detect the diseases at the first symptoms because the strategies and the products authorized in organic farming are only effective if they are used in time. Fortunately, we can also benefit from the support of local phytopathological bulletins, which offer indications on the development of certain phytopathologies on a territorial scale.
The most typical fungal diseases of cherry trees are monilia and coryneum to which is added one of bacterial origin called bacterial cancer .
Contents [Ocultar]
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Monilia
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Corynea
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bacterial cancer
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How to prevent diseases
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Containing diseases by biological methods
Monilia is a fungal or cryptogamic disease typical of cherries and other stone fruits (peach, apricot, plum). It is caused by two different fungi (Monilia laxa and Monilia fruttigena) and is favored by a humid climate, not necessarily hot. Already in early spring, before the flowers open, if the plant stays wet for a few hours, an infection can develop. On the affected plant, the flowers darken, dry out and sometimes become covered with gray mold. The twigs tend to split lengthwise and eventually dry out, while the fruits rot and mold. Unfortunately, very wet springs can be detrimental to cherry trees, with monilia infections continuing until temperatures exceed 27-28°C.
Corinea
Coryneum, also called shotgun, gummy, or stinging, is caused by another fungus that shows up on the leaves as small red-purple spots surrounded by a halo. It is a very simple symptom to recognize: the leaf of the affected tree remains perforated because the inside of the spot tends to detach. The branches have cracks from which gummy slime oozes out, and even on the cherries you can notice small red spots that turn into gummy encrustations as they ripen. This pathology is also favored by wet seasons.
Bacterial cancer
The bacterium, of the genus Xanthomonas, affects not only cherry but also other drupaceae, the disease causes irregular spots on the leaves and mainly damages the stem and branches, with lesions and necrotic areas.
How to prevent diseases
In organic farming, prevention is very important: if you manage to create an environment that is not conducive to the proliferation of diseases, it will not be necessary to treat the plants, the cherry tree remains healthy and productive. So let’s see some precautions we can take when growing this fruitful plant.
- Variety to choose from. In order to prevent diseases, the decisive choice concerns the varieties to be planted: in the organic garden, preference should be given to genetically resistant or tolerant varieties. This is a first warning that avoids most problems.
- Pay attention to the size. Size is another important factor, as a humid microclimate favorable to the pathogen could be created within dense foliage. Especially in the case of bacterial cancer, it is essential to disinfect the pruning tools when changing from a diseased plant to a healthy one. It is also necessary to remove all parts of the plant that are affected by the symptoms of the disease at any time of the season, this also avoids contagions that spread the problem.
- Fertilization . Fertilization must also be balanced to avoid adversity. Every year it is good practice to distribute granulated manure under the projection of the cherry tree canopy, but without exaggeration because even organic fertilizers in high doses cause excessive nitrogen absorption by the plant, which becomes more susceptible to attack. diseases. and aphids.
- Useful macerates. As for the autonomous preparation of products that stimulate the natural defenses of plants, spring is a good time to harvest horsetail and dandelion, excellent for use in the preparation of macerates with reinforcing action.
Containment of diseases by biological methods
After the fall of the leaves in autumn, it is useful to carry out a treatment based on Bordeaux mousse on bare plants, but this fungicide commonly known as “Copper Green” should always be used after carefully reading the instructions on the package, which includes following the dosages, suggested methods and precautions. Copper is, indeed, an allowed element in the organic method, but not without possible consequences.
The same attention should be paid to the use of calcium polysulphide , another fungicide authorized in organic farming, effective for monilia but to be avoided during flowering. It is worth remembering that calcium polysulphide is very corrosive for the equipment used to distribute it and that these must be carefully washed after use.
For a more ecological direct defense against cryptogams, products based on antagonistic organisms can be used What Bacillus subtilis at night to be effective or the fungus Trichoderma harzianum . It can also be treated with Sodium bicarbonate dissolved in water at a dose of about 50 g in 10 liters.
Finally, let us mention a disinfectant preparation used successfully in biodynamic agriculture, namely the log paste . It is a dense preparation that is spread on resting plants from the base of the trunk to the first branches to clean the trunks of forms of fungi and overwintering insects. There are also more liquid formulations to distribute with the backpack pump, therefore more suitable for large orchards. The traditional recipe includes one-third fresh cattle manure, one-third bentonite and one-third silica sand, to which other ingredients such as horsetail decoction can be added.