Content
Currant bushes are susceptible to fungal diseases that affect the entire plant, reducing its immunity and winter hardiness. Without timely treatment, plantings may die. In spring and early summer, the development of black and red currant bushes is closely monitored in order to prevent such an insidious disease as anthracnose.
How does the disease manifest itself?
Anthracnose infection of currants begins in the spring. The causative agents of currant anthracnose, having overwintered on fallen leaves, are spread by insects during rain. Plants with minute mechanical damage are often affected.
Causes of the disease
This fungal disease is caused by marsupial fungi of several genera. The disease affects the leaves and shoots of many plants, especially currants - red, white and black. The smallest spores, conidia, once on the plant, form a mycelium in the tissues between the cells. The incubation period after exposure to the spores that cause anthracnose on black currants is approximately 2 weeks. Red currants get sick within a week. Having developed, the mycelium produces two generations of conidia - in May and July.
The summer season is favorable for the development of the disease with frequent rains, when the humidity reaches 90% and the air temperature is 22 0C. In such years, the widest spread of the disease is observed. In dry years, cases of infection are much less common. It has been noticed that plants located on acidic soils, as well as those with a lack of potassium and phosphorus, often suffer.
Routes of infection
Anthracnose spores are transmitted from diseased currant plants to healthy ones in several ways:
- Spread by insects and mites;
- Air currents;
- The disease is promoted by dense plantings of currant bushes and remaining last year's leaves.
Signs of infection
With anthracnose, leaves, petioles, young branches, stalks and, less often, berries are affected.
- A symptom of an incipient disease are dark or light brown spots of a round shape, with a darker border, ranging in size from 1 mm. Over time, the spots increase in size and merge into a large affected area on the leaf blade, which becomes dry and falls off;
- Later, from mid-summer, a second sporulation develops, noticeable by black tubercles. When they ripen and burst, they turn white. The disease, through new pathogens, covers a large area of the plant and can last until September;
- The shoots, as well as the petioles and stalks of red currants, are covered with dark depressed spots that prevent the free flow of nutrients;
- Later, cracks form in place of the spots on the shoots. When wet weather returns, the shoots rot;
- If the disease spreads to berries, it is recognized by small glossy black or brown dots with red edges;
- At the stage of leaf fall, young shoots wither;
- In July, only new leaves may remain on the bush.
Consequences of the disease
You can assess the condition of a diseased blackcurrant bush in mid-summer, especially if the temperature stays below 19 degrees. On red currants, the disease appears earlier - at the end of May, early June, if the temperature range ranges from 5 to 25 degrees. Leaves from red and white currant bushes fall off almost immediately after defeat. On black currants, browned and dried, curled leaves sometimes remain until autumn. With unhindered development, up to 60% of the leaves fall off, the plant does not receive enough nutrients. The yield of a diseased bush is lost by 75%, the sugar content of the berries is reduced, young shoots are not formed, and up to 50% of the branches may die over the winter.
Fungi that cause anthracnose overwinter on fallen leaves. If they are not removed from under currant bushes, in the spring they produce new spores, and the bush becomes infected a second time. It happens that the disease goes away, but the plant weakens and without treatment and support may not recover.
Control measures
Knowing the symptoms of the disease, gardeners take preventive measures to combat anthracnose on currants, carefully removing fallen leaves in the fall and digging up the soil under the bushes. Treatment with chemicals helps to destroy the causative agents of currant disease.Each gardener chooses his own option from a range of drugs for the treatment of currant anthracnose. The bushes are sprayed in dry weather, when there is no wind, carefully treating each leaf.
Processing options
- Before the buds open, use 1% copper sulfate, treating the bushes and the soil under them;
- Captan, Fthalan (0.5%), Cuprozan (0.4%) or 3-4% Bordeaux mixture are applied to unopened buds, before flowering or 10-20 days after harvest;
- Before flowering, the fungicide Topsin-M is also used in a mixture with drugs that stimulate the immune system: Epin, Zircon;
- Currants are sprayed with Zineb or 1% Bordeaux mixture after flowering;
- If anthracnose is detected on currants during the ripening period, treatment is carried out with microbiological preparations: Fitosporin-M, Gamair;
- After picking the berries, the currant bushes are re-treated with fungicides Fundazol, Previkur, Ridomil Gold or others.
Prevention
Correct spacious planting and pruning of currant bushes, soil care, removal weed, moderate watering, careful inspection and regular preventive spraying will protect plants from treatment for anthracnose disease.
Preventive treatments are carried out with drugs that protect plants from a wide range of fungal diseases and pests. Fungicides Cumulus DF, Tiovit Jet, Tsineb, Captan, solution 1% Bordeaux mixture is used after flowering and 15 days after picking the berries.
Having noticed the first signs of anthracnose, the affected parts are removed so that the disease does not spread.In autumn, fallen leaves are collected and the soil is dug up.
From the experience of summer residents
Not all gardeners like to use chemicals, but treat currant anthracnose with folk remedies weekly.
- In March or February, which depends on the region, the bushes are scalded on the dormant buds with hot water, the temperature of which is not higher than 70 0C;
- Spraying the bushes with a solution of laundry soap is used to treat currant anthracnose. Half the bar is grated and diluted in a bucket of water, temperature not lower than 22 0C;
- Currant bushes are treated with an infusion of 150 g of chopped garlic and 10 liters of warm water: the pungent odor repels pests and one of the pathways for the spread of currant anthracnose is interrupted;
- An iodine solution is used in the treatment of currant bushes. Its antiseptic property is equivalent to the action of a fungicide. Iodine destroys microorganisms and provides preventive support to plants. For a working solution, dilute 10 drops of iodine in 10 liters of water.
Top dressing
Plants with developed immunity are easier to treat. Currants are supported with complex supplements.
- For a 10-liter bucket of water take 1 tbsp. a spoonful of potassium sulfate and ammonium nitrate, half a teaspoon of boric acid and 3 g of ferrous sulfate. Fertilizing restores a depleted currant bush, helps to grow greenery and prevents chlorosis of leaves;
- In the phase of ovary formation, fertilizing with wood ash is prepared to improve the quality of the crop and increase the endurance of currants. Dissolve 200 g of ash, 1 bag of sodium humate, 2 tbsp. in a bucket of water. spoons of potassium sulfate and 1 tbsp. a spoonful of superphosphate;
- The use of “Immunocytophyte” has a good effect: 1 tablet of the drug is diluted in a bucket of water, add a solution of 1 tbsp. spoons of superphosphate and 2 tbsp. spoons of potassium sulfate.
When buying currants, you can choose varieties with high resistance to anthracnose:
- Black currants: Stakhanovka, Katun, Altai, Exhibition, Daughter of a Siberian, Zoya, Belarusian sweet, Golubka, Elegant;
- Red currant: Faya fertile, Firstborn, Victoria, Chulkovskaya, Red Dutch, London Market.
The disease brought by fungi can be defeated. Increased attention to the garden will bring a high-quality harvest.
