What is raspberry anthracnose and how is it treated?

It is a shame when, instead of bearing fruit, the berry bushes start to hurt, and sometimes die. Raspberry anthracnose may well cause such consequences if you do not take timely measures. The causative agent of the disease is widespread and often affects plants that are weakened or grown in unfavorable conditions.

The reasons for the development of the disease

The disease is caused by the pathogenic fungus Colletotrichum orbiculare. The primary infection enters the bushes in the form of mycelium, then with the help of small colorless conidia it spreads to the entire plant, gradually capturing it completely.

Mycelium hibernates directly on the affected shoots, and in the spring begins active sporulation. In conditions of high humidity due to heavy rainfall and dew, Colletotrichum orbiculare multiplies at an accelerated rate. The optimum temperature for the development of the fungus is +20 ° C.

Conidia need moisture to germinate, a process that takes 3 to 12 hours. The first symptoms of the disease will appear 1–1.5 weeks after infection. Most often, the mycelium is brought onto the site along with diseased seedlings, but there may be other transmission routes. The pathogen hits the raspberry:

• from an infected tool;
• through contaminated soil;
• from uncleaned plant residues;
• during the rain;
• when using seeds that have not been disinfected;
• with insects.

The spread of the disease does not have a rapid course within the site. However, the raspberry anthracnose pathogen can infect some other crops as well. The same fungus is dangerous for gooseberries, grapes, currants.

Symptoms of raspberry anthracnose

Raspberry anthracnose is classified as a disease with a high degree of severity. The manifestations of the disease can be seen on leaves, shoots and berries:

• first of all, small rounded spots of grayish-brown color with dark edging appear on the leaves;
• under conditions favorable to the development of the disease, the affected areas soon merge, and then foci of necrosis appear in these areas;
• longitudinal brown strokes appear on young branches, which later transform into purple rings, covering the shoots;
• as a result, the supply of nutrients important for the plant is disrupted, the shoots stop receiving the necessary elements and water;
• in the future, the affected areas crack and can rot.

The peak incidence occurs in July-August. At the final stage of the disease, the leaves and flowers fall off, the tips of young shoots die off before the harvest ripens, the fruits stop developing and dry out, sores of various depths appear on the branches and shoots. In winter, the affected shoots are susceptible to freezing.

Preventive measures

The goal of any summer resident should be to prevent the development of the disease, and not to fight it. Agrotechnical techniques will help to ensure that the plantings of raspberries remain healthy:

• Use of quality planting material. You need to buy seedlings only in proven places. The bushes are carefully examined at the time of purchase. The leaves should have a deep green color. Do not buy a plant that has suspicious stains and damaged areas on its foliage.
• It is necessary to apply balanced fertilizing, accurately observing the dosage of fertilizer and doing it on a regular basis. Organic matter should be preferred. In the fall, preparations with phosphorus and potassium are introduced for digging.
• Preventive treatments using copper-based fungicides, as well as preparations of the group of triazoles and dithiocarbamates. Most often, summer residents use copper sulfate for spraying. Processing is carried out in early spring, during the budding period, after picking berries, before wintering.
• The bushes in the raspberry bushes must be thinned regularly so that the plantings are well ventilated. Stagnant air tends to build up moisture.
• The trunk circle of each plant must be kept clean by timely weeding, removing plant debris and digging up the soil.
• Affected shoots must be immediately cut to zero and destroyed by burning or deep burying in the ground. You should also pick off diseased leaves and berries.

In addition, it is advisable to choose anthracnose-resistant raspberry varieties that have appeared due to breeding work. Among them:

• "Gloria",
• "Meteor",
• "Patricia",
• "Scarlet Sails",
• "Cascade",
• "Bryanskaya" and many others.

When planting between the bushes, be sure to keep a distance.

The choice of a place for laying a raspberry tree also plays an important role. The site should be well lit by the sun, protected from winds and located away from fruit trees, vineyards and other fruit bushes. It is recommended to plant basil, garlic, onion, celery nearby.

In order to protect raspberries from anthracnose, you can place a flower bed with calendula, pyrethrum or marigolds next to them, grow wormwood, tansy. Row spacings can be sown with green manure. These plants rid the soil of pathogenic microorganisms and improve its structure.

Control methods

The fight against raspberry anthracnose is effective only when chemicals are used. Folk remedies are used as a preventive measure.

Decoctions and infusions based on plants, soap solution help protect raspberries from pests, which are often the culprits of the disease. Infection easily penetrates into leaves damaged by insects. In addition, pests weaken the plant, and its immunity decreases.

Industrial fungicide applications

If the raspberry tree is badly affected, you will have to sacrifice the crop and start spraying with chemicals, otherwise the berries may completely disappear. Harvesting diseased plants will still not be possible.

For the prevention and treatment of anthracnose on raspberries, the following drugs are used:

• Copper sulfate. Vitriol is used in 1% concentration, that is, 100 g of the drug is diluted in a bucket of water. During the growing season, it is not used due to its high toxicity. The treatment is carried out until the bud breaks and late in the fall, especially if there was an outbreak of the disease in the previous year. The same solution must be watered on the stems at the base of the bush and the soil around the raspberries. The drug also helps against septoria, as well as other spots.
• "Oxyhom". It is mainly used for preventive treatment in spring and autumn. The drug helps to prevent not only anthracnose, but also purple spot. The working solution is prepared from 30 g of "Oxychom" and 5 liters of water. Once in the vascular system of the plant, the drug provides internal protection against fungus.
• "Cuproxat". The agent has a devastating effect on fungal spores. Does not cause toxic damage to pollinators. With symptoms of the disease, the drug is used only at the initial stage, in advanced cases it is ineffective. Prepare a solution using 6 ml of concentrate per 1 liter of water (consumption per 10 m²).
• "Propiconazole". The fungicide also helps against purplish spot, rust and septoria. To prepare the solution, use 7-10 ml of the drug per 10 liters of water. It is recommended to spray before flowering and after picking. Double processing is required.
• "Acrobat-MC". Systemic local fungicide. Protects raspberries from fungus inside and outside, penetrating into plant tissues. The consumption of the drug is 20 g per 5 liters of water.Compatible with other products, so it can be used in tank mixes. Not only warns, but also treats anthracnose. Prevents the formation of new spores. Raspberries are sprayed with the solution twice with an interval of 14 days.

For spraying, a manual or pneumatic sprayer is used. When buying it, the area of ​​the cultivated plantation is taken into account. The sprayer can have a tank volume of 5 to 16 liters.

The treatment is carried out in dry, calm weather in the morning or on a cloudy day. You need to take care of the means of protection. Usually they use a protective mask, gloves, closed clothing. After working with chemicals, wash your face and hands thoroughly, rinse your mouth.

Strengthening plant immunity

Since anthracnose is mainly susceptible to weakened bushes, it is necessary to take care of strengthening the immune defenses of plants in advance. To do this, root fertilization is carried out and growth stimulants are used. When caring for raspberries, fertilizers must be applied containing high doses of phosphorus and potassium.

Ready-made preparations can be replaced with wood ash: it serves as an excellent source of essential trace elements. Additionally, the agent "Baikal Em-1" is used, which is an environmentally friendly fertilizer that increases the number of berries and improves their taste. Treatment of bushes with the drug is carried out 2-3 times per season. It is recommended to do this at the time of the formation of the ovary and at the stage of milk ripeness of the berries.

The last feeding should be carried out no later than the end of August. EM compost has a similar effect; it is used as a mulch layer. As a result of the use of such mulch, the soil is enriched with beneficial bacteria that prevent the growth of pathogenic microflora.

Potassium humate and "Epin-extra" activate the defenses of the plant, their use increases the resistance of raspberries to most fungal diseases, including anthracnose. Spraying is carried out several times:

• in early spring;
• during the period of bud formation;
• 2 weeks after flowering;
• when pouring berries.

Anthracnose protection should begin at the stage of laying the raspberry tree. It is necessary to choose the right place, observe the landing pattern. In the future, it is impossible to deviate from agricultural technology - it is necessary, on the contrary, to create all the conditions for the shrubs for normal development and growth. If the disease was nevertheless detected, measures are taken at the first symptoms, only in this case there is a chance to save the crop.