WALNUT ANTRACNOSIS (KARALEKE)
The cause of walnut anthracnose is a fungus. In the spring, when the walnut seedlings' eyes wake up, the factor that completes its development on the dead leaf tissues transmitted from the previous year, according to the rainy weather of the air, infects from the period after the leaflets on the branches develop after passing the half size. For some years, when the mealy fly is heavily in the air, they may find very few leaflets to infect due to the late cold, walnut leaflets that are extremely sensitive to cold from the cold.
Symptoms of the disease appear on the leaflet, fruit, young shoots and leaf stems of the walnut tree. Although it is mostly a leaf and leaflet disease, very sick is also seen in the green fruit peel of walnut fruits.
Walnut tree begins in mid-summer due to the disease, early leaf fall begins, with the edges covered with necroses curled, roasted or completely dead. In some epidemic years, the tree may remain completely leafless before autumn arrives. When the green peels of sick walnut fruits are removed, dark spots appear on their hard peel and such fruits quickly rot during storage.
In some years, although the amount of the first symptoms is small, the disease spreads rapidly and the symptoms increase suddenly in the rainy seasons that start in June and sometimes go from July to sometimes August, with morning and day temperature differences. This situation should be taken into consideration very well especially in the fight.
Since the disease attracts attention as a walnut leaf disease, it decreases the assimilation surface of walnut saplings and negatively affects the formation of shoots and fruit for the coming years and causes low productivity. The disease is seen in many varieties of walnut saplings in our country and especially in places where the relative humidity is high, wherever walnuts find a growing environment and at every elevation. It occurs more in low places than in high places, in stream length, slopes and valleys compared to open areas.
As a cultural precaution, walnut sapling leaves poured on the ground, which are sources of contamination, should be collected and burned in autumn. Branches belonging to previous years with spots of the disease and deep wounds should also be pruned.
In chemical control;
1st spraying: In the period when the walnut buds have just started to burst and the leaves are cat ears,
2nd spraying: In the period when the leaflets take half the size,
3. Medication: It is done in the period when the walnut fruits take the nut size.
Medications should be discarded so that the medication covers all walnut trees and there is no remaining medication. In very high trees, medication should be attempted to be as high as the spray can reach. Spraying should be avoided in rainy weather.
The causative agent is a capped fungus. He creates his hats after the first rains of autumn. Hats that are yellowish brown on the roots of sick walnut trees or on dead woods and woods in the form of a cluster and turn black down are 5-15 cm in diameter. Fungus lives both in soil and wood texture, and lives for a long time in dead walnut trees and root fragments remaining in the soil. It finds good development in damp places.
In the walnut seedlings that catch the disease, the formation of shoots decreases, the leaves turn yellow and fall off, the shoots and branches begin to die and dry, and finally the walnut trees completely dry. At the beginning of the disease, the wood tissue is light brown, then it turns into yellowish or spongy tissue.
As a cultural precaution, dried walnut seedlings should be completely removed, especially their roots, and quicklime should be poured into their pits. For several years this area should not be used for fruit. Contamination from the surrounding gardens by irrigation should be prevented. Walnut garden should not be constructed immediately after opening the forests and a few years should be waited. Walnut seedlings should not be planted deeply and excessive watering should be avoided.
If the disease has just begun; After the patient's roots are cut and the patient parts are cleaned, a 5% Bordeaux Slurry, 2% Tear or 5% Karaboya drugs are applied with a brush, after drying, the vaccine paste or 750 g juniper tar + 250 g Bluestone mixture closed with. If the walnut roots are completely sick, they should be removed up to the thin roots and burned in their pit, and quicklime should be poured.
In order to protect the solid trees in the sick walnut sapling garden, the soil should be irrigated by giving 10 liters of water to each m2 with 5% Karaboya or 2% bluestone in each fall of the crown projections of trees when entering autumn or spring .