How to deal with white spot (ramularia) on strawberries and strawberries?

White spot or ramulariasis is caused by the pathogenic fungus Ramularia tulasnei. The disease often affects poplars, develops on bushes of tomatoes, strawberries and strawberries. Berry crops are affected by ramularia in all regions where they are grown. Since the causative agent of white spot remains in the soil for up to 8 years, the issue of treatment and prevention of the disease always remains relevant.

Where does white spot come from?

Often the fungus Ramularia tulasnei is already present in the soil or gets into it along with infected plants. The causative agent of white spot is able to survive the winter, remaining in the upper soil layer under leaf litter. After the snow melts and the earth dries up, the fungus moves to the lower leaves of strawberries and strawberries.

It may take some time to notice the signs of illness. At the initial stage, conidia mature, and their mass distribution occurs at the end of June. If you do not take action, by the last days of August the disease spreads throughout the plantation, affecting the leaves, whiskers and fruits of the berry.

Warm weather and high humidity contribute to the growth and spread of the fungus. The optimum temperature for the development of white spot is 20-22 ° C. The disease develops more actively on heavy clay soil fertilized with organic matter. Fungal spores are easily carried by the wind, so it is best to set up a strawberry plantation in a place protected from drafts.

Disease manifestations

The first signs of the disease appear in early spring. Reddish dots form on young strawberry leaves, which grow over time. In the active stage of the development of the fungus, the points turn into whitish spots with a dark brown rim. Often, the affected tissue dries up, and through holes are formed in its place.

With a significant area of ​​leaf damage, photosynthesis worsens, which means that the yield decreases. If the disease has affected a significant part of the plantation, the loss of berry yield can be 20-30%. The taste of strawberries also deteriorates.

Preventive actions

It is possible to prevent the development of white spot with the help of a number of agricultural techniques aimed at suppressing fungal infection and reducing the number of pathogenic microorganisms. To do this, you must do the following:

• Timely remove fallen leaves of diseased plants and burn them. Such organic material is not suitable for laying in a compost heap, since in conditions of heat and high humidity, the fungus will begin to actively develop.
• Weed the strawberry beds regularly. Weeds, growing up, interfere with the normal ventilation of the bushes, respectively, create favorable conditions for the development of fungal infection. You can replace weeding by mulching the soil. Mulch will prevent fungus from entering the plant leaves from the soil and will additionally serve as fertilizer for strawberries.
• Use EM drugs. These products are completely natural. They improve the general condition of the soil and inhibit the development of fungal microorganisms. This group includes drugs "Baikal EM-1", "Emochki", "Agrozin". It is the good condition of the soil that will prevent the growth and spread of the fungus. In addition, strawberries growing on such land become healthy and strong, their immunity is able to cope with the infection on its own.
• Avoid excess nitrogen fertilizers. A large amount of nitrogen in the soil contributes to the rapid growth of the fungus. You need to be especially careful with the use of organic food such as chicken droppings.
• When replacing old strawberry bushes with new ones, do not reuse the same bed. The culture is returned to its original place not earlier than after 5 years. During this time, other garden crops can be grown on the site. For example, plant carrots, cabbage, greens, onions, legumes, lettuce next year.

It is necessary to carefully inspect the seedlings before buying, so as not to bring the fungus along with the planting material. At the slightest suspicion of white spot, it is better to refuse to purchase such plants. Preventive measures include the selection of disease-resistant varieties.

Treatment with folk remedies

In the fight against white spot on strawberries, folk remedies work well. At the same time, they stop giving the plants nitrogen feeding and add potassium. Solutions used to treat fungus are prepared from the following components:

• Wood ash. A liter can of wood ash is added to 10 liters of water and insisted for a day. Before use, the infusion is diluted with water in a 1: 2 ratio. You can simply sprinkle ash powder on the soil under the bushes, scattering it with a strainer.
• Potassium permanganate. Prepare a solution of 5 g of the substance per 10 l of water. Potassium permanganate crystals are stirred in a liquid until completely dissolved and sprayed with bushes.
• Soda and iodine. To prepare the solution, you will need 30 drops of iodine and 1 tbsp. spoon of baking soda in a bucket of water. The mixture is thoroughly mixed, and then used to treat bushes and soil.

The bushes are sprayed with any of the prepared solutions, and the rest of the composition is poured under the root, spending 0.5 liters for each plant.

It is recommended to use folk remedies at the initial stage of the disease. To enhance adhesion, you can add 40 g of crushed laundry soap per 10 liters of liquid to the solution. With a strong degree of infection, chemical preparations will give a more reliable result.

The use of chemicals

Usually summer residents try to avoid chemistry when treating fungal diseases during the period of berry setting and active fruiting. However, if the lesion is severe and the young strawberry is infected, it is still worth using chemicals to save the plantation. It is better to treat ramulariasis with long-acting drugs.

Ridomil Gold

Using "Ridomil Gold" for the defeat of leaves, you can cure strawberries from white spot with 2-3 treatments, each of which should be repeated after 2 weeks. This drug of systemic action has proven itself in the treatment of many fungal diseases, including ramulariasis.

If in the previous season strawberries were sick with white spot, "Ridomil Gold" is used for preventive purposes in early spring. The drug is dissolved in water (25 g of powder per 10 l), the soil is spilled with the prepared solution. The components of the product are absorbed by the root system and penetrate into plant tissues. If you start processing in the spring before the berries appear, you will be able to defeat the disease.

"Topaz"

"Topaz" is a general purpose fungicide. Most horticultural and horticultural crops are treated with it, fighting fungal diseases. The agent is used for preventive and therapeutic purposes. The best effect is obtained by using it at the beginning of the growing season.

It is a one-component drug based on the substance penconazole, which prevents the germination of fungal spores. Feature of "Topaz" is that it is absorbed very quickly, so it can be used even during the rainy season. The temperature difference also does not reduce the effectiveness of the drug.

To prepare a solution, an ampoule with a volume of 2 ml is poured into 10 liters of water and mixed thoroughly. The active ingredient is completely absorbed by the leaves within 3-4 hours.After processing, re-spraying is necessary after 14 days. The composition begins to act immediately after absorption. "Topaz" is compatible with many other drugs, so it can be used in combination.

"Horus"

The advantages of the drug include its effectiveness at low temperatures and a short disintegration period (1.5–2 weeks), after which it becomes safe for humans and the environment. The mechanism of action of the fungicide is based on the fact that it prevents the germination of fungal spores.

"Horus" cannot affect the matured fungus because of the hard shell, therefore it is advisable to use it for prevention and at the initial stages of the disease.

The opened package cannot be stored, the product must be used at one time. The working solution for spraying strawberries is prepared from 6 g of fungicide per 10 liters of water. It makes sense to fight white spot on strawberries with this remedy only before flowering, at a later stage it is useless to spray.

Preventive treatments with fungicides against fungal diseases have long become the norm when growing berry crops. It is better to take measures to prevent the spread of the disease than to fight it for a long time and persistently. Especially when it comes to white spot, the pathogen of which persists in the environment for a long time.