Why do strawberry leaves turn red and what to do about it?
Strawberries are a favorite berry for both children and adults. But how much work it requires, only those who grow it know. Plant care includes fertilizing, timely watering, and the fight against various pests and diseases. In this article, we will talk a little about the confrontation with the redness of the leaves, which is a manifestation of the disease (various spots).
Causes of the phenomenon
Only in autumn, strawberries, like many plants, at the call of nature, change their emerald outfit to crimson and gold. This is a natural process, and there is nothing to be afraid of. At other times of the year, red spots on your pet's green leaves are the first sign of spotting.
There are several types of this disease.
- White or ramulariasis (scientific name). When infected with this variety, the foliage is covered with a white bloom, the spots themselves, increasing, brighten, but retain a red or brown border. With a large area of planting damage, you can miss up to 35-50% of the leaves, which will negatively affect the quantity and quality of the harvested crop (the surface area of the greenery involved in photosynthesis decreases). The first signs may appear in the middle of the last month of spring, the peak of flowering is in June (at the end of fruiting). The disease expands the zone of its defeat with conidia (white plaque on spots). The incubation period is from 17 to 24 days. One of the factors contributing to the appearance and development of this dirty trick is high humidity and heat.
And it was also noticed that on clay soil with an excess content of humus, it is more common. In the soil, spores can survive up to 8 years.
- Brown. With this disease, the spots are often brown and also with a border, clearly visible on the reverse side of the leaf, but do not turn white when enlarged and are located closer to the edge of the leaves. The second name for this misfortune is angular spotting. It is dangerous because it infects plants at the end of summer, at a time when our pet begins to tie flower stalks for the next season, and at the beginning of autumn, diseased leaves dry up. Be vigilant, do not confuse with natural autumn wilting.
- Brown. It causes the appearance of brown and red-brown spots of the same saturation. If white and brown spots mainly affect only the leaves, then the brown one moves to both the mustache and the stems of the plant. It is she who is the main reason for the first reddening, and then the drying of strawberry foliage, and ultimately leads to the death of the bush. Another difference is that it is in a hurry to appear in all its glory, and even before your beautiful strawberry blooms, you can notice its signs, most likely already of a secondary infection. According to some summer residents, the primary lesion occurred in the previous season in the phase of fruit formation, and by August it will affect the entire plant. At the same time, a black “fluff” is formed on the back of the sheet - ripe spores of the pathogen.
With a wide distribution, it can affect from 60 to 100% of the foliage.
With verticillium, the fungus infects the root system, therefore, during flowering and fruit formation, the plant lacks nutrients and this is reflected in the leaves - at first they become lethargic, then turn red and gradually fade.This disease arises from oversaturation of the soil with moisture. The first manifestations can be seen during the blooming of flowers, the setting of strawberries. It is also possible the appearance of red leaves in strawberries due to the increased acidity of the soil, lack of phosphorus, nitrogen or potassium. But plants grown on acidic soil do not dry out.
Prevention
Of course, in any case, it is better to prevent reddening of the foliage than to fight the disease. If you plant purchased seedlings, purchase them only in trusted nurseries or specialized stores - they monitor the quality of their seedlings, as their reputation directly depends on this. You should not buy strawberry bushes from your hands - the risk of acquiring fakes or diseased plants is not worth the saved rubles. The roots of purchases should be treated with a weak solution of potassium permanganate. And the foliage should be washed for a quarter of an hour with hot water (temperature of about +45 degrees Celsius).
Carefully choose a place for future beds. Basically, strawberries are unpretentious to the ground (with the exception of remontant), but on a soil that is too poor in nutrients, you are likely to get a small, tasteless berry. If the earth is acidic, it is poor in phosphorus - one of the most important elements required by the plant for normal growth and development. But the process of its assimilation is also associated with a sufficient content of nitrogen in the soil.
Before planting plants, the soil should be treated with a solution of ash and nitrogen fertilizers.
And also remember that the transmission of infections usually occurs with the help of wind and water. You need to try to raise the strawberry beds 50–70 cm above the level of the rest of the plantings. It is worth organizing the correct watering of your favorite beauty nurse, while monitoring the water temperature.Don't forget about adequate drainage of the beds. It should be remembered that strawberries are a two-, maximum four-year-old crop. Do not forget to change the landing sites, while observing the rules of crop rotation. It is best to plant strawberries after alfalfa, clover and other perennial grasses.
Planting should not be done too often - thickening leads to more rapid depletion of the soil, and increases the risk of the spread of various infections, as well as pests. To prevent fungal diseases in early spring, it is worth spraying the bushes with Bordeaux liquid, because all spotting, like verticillium, is caused by phytopathogenic fungi. The second treatment is carried out after the end of the fruiting season. Bordeaux liquid can be replaced with an ammonia solution with the addition of potassium permanganate and brilliant green (colloquially, “potassium permanganate” and “brilliant green”) if no signs of infection are found.
Many summer residents use Horus phytoncide. For the initial spring treatment, 12 g per 10 liters of water is enough, and the second time, after harvesting, the solution is made twice as weak. To prevent verticillium wilt, you should carefully follow the rules of crop rotation, because the pathogen in the ground remains viable for 6 years.
Treatment
At the first signs of the disease, it is worth treating the plant immediately. Do not leave infected plants in the garden. If there is a suspicion of spotting, remove the reddened leaves. If this is verticillium wilt, it is worth removing the entire bush, then burning it. One or two uprooted plants should not be regretted - this will save the rest. You should cut off the antennae and forget about the reproduction of your pet this season - most likely, you will get diseased seedlings.
The main thing is the warning spraying of the soil. Unfortunately, during the period of flowering and fruit formation, strawberries should not be treated with chemicals, because toxic substances accumulate in the berries. Therefore, for the most part, treatment comes down to preventive cultivation of the land in spring and autumn with preparations containing copper. As they are used drugs "Topaz", "Skor", "Zircon" and Bordeaux liquid. "Fitosporin" can be used several times per season, because it is considered quite safe.
There are also folk ways to deal with spotting. The first is the already mentioned "potassium permanganate". And here is the second eco-friendly composition: mix 30–40 g of any soap (of course, crushed into shavings), 20 g of ordinary soda, 30–50 g of iodine. The resulting mixture should be shaken in a bucket of water. Processing is carried out in the phase of the affected lower leaves. If the culprit in your strawberry garden is a fungus from the Verticillium family, you are out of luck.
At the initial stages of the development of the disease, treatment with fungicidal preparations can help, but if the disease is missed, the strawberries will die. We'll have to plant new seedlings, and not in the old place.
If strawberry foliage is turning red due to “starvation” - insufficient content of essential macronutrients - most likely, it can be revived this season. But this does not mean that you should give up and do nothing. Top dressing is necessary, and better complex, combining both mineral and organic components. They can be made with your own hands: you should take 1/3 of a bucket of humus and 5 g of potassium-containing fertilizers (for example, potassium nitrate is suitable). Mix them in a large container, pour 7-8 liters of water and leave for three days.The dressing prepared in this way must be diluted: 1/10 fertilizer to 9/10 water. It is necessary to water it with caution - in no case should it be sprayed on leaves and petioles.
If possible, it is worth ordering a soil analysis, then you will definitely know what your sweet nurse is missing. If there is a lack of nitrogen in the soil, nitrogenous or complex "vitamins of the earth" (ammonium nitrate, nitrogen phosphate and others) should be used.
If phosphorus decided to "walk", it is worth using preparations with a high content of this element (superphosphate and others). And also organic fertilizers will not interfere - if you use a two-line method of seating bushes, it is worth laying manure in the gap between the rows. Potassium starvation can be "cured" by feeding plants with potassium-containing compounds.
For information on what to do if strawberry leaves turn red, see below.