Among fungal infections affecting vegetables, the most insidious is late blight on potatoes, tomatoes, and other plants. Now we will talk about root crops. For many years of experience growing nutritious tubers, I learned to cope with this scourge. Although the pathogen cannot be completely eradicated, prevention helps to keep the disease in check. Under adverse conditions, the crop can be saved if treatment is started on time.
Description of late blight
Late blight is a putrefactive disease caused by micellar microorganisms called Phytophthora. Fungi can infect many crops. Penetrating into the earth, they persist there for many years. They are waiting for favorable conditions for development.
What do late blight lesions look like:
- Dark watery spots appear on the leaves, they grow, become brown. A whitish coating appears on the leaves below - these are bags. In which disputes develop. The fungus eats away all the tissues of the bush. The tops can darken completely, dry on the vine.
- Gray-brown spots appear on the tubers, the potatoes become uneven, with dents. During storage, the spots increase, become dark brown, soft. The rotten flesh on the cut is clearly visible, recognizable by an unpleasant odor. Over time, turns into mucus.
If you do not fight the fungus when the first signs of infection appear, the whole crop will die in the cellar and cellar before spring. With a massive defeat, fungicides will help to save at least something, I will say more about them.
Causes, symptoms of damage to potato late blight
First, a few words about the methods of spreading spores. They are in addition to the wind:
- rodents;
- people on clothes, shoes;
- pets;
- birds;
- insects, the same Colorado potato beetle, butterflies.
The infection can be brought into the soil:
- when planting infected seed material, insidious late blight on tubers does not appear immediately;
- using unprocessed tools, containers;
- if you make compost from the overripe diseased tops;
- with manure;
- when watering contaminated water from open reservoirs, barrels; when favorable conditions arise: the temperature drops, the rains begin.
With increased humidity, the contrast of night and daytime temperatures, the mycelia swell and begin to develop. Burst, seeding nearby plants. Even single, spotted rotting is dangerous. By the way, if tomatoes are affected in the greenhouse or spotting has appeared on apple trees or berries, urgently need to control the planting of potatoes, spray them to prevent late blight.
By the way, it is better to dig the affected potatoes ahead of schedule, if these are single bushes. From infected plants, the crop is harvested and stored separately from the rest of the potatoes. Use in the first place.
The infection spreads through the plant from bottom to top, first leaf plates located near the ground, then the trunk, the top. Cells dry out, dehydrate, leaves, trunk become fragile.
Why phytophthora is dangerous for potatoes and humans
I was not surprised when I read that due to late blight, up to 25% of the crop dies annually. In rainy, cool years, gardeners lose much more. Phytophthora, under favorable conditions, spreads very quickly, is transferred to other crops, enters the earth, water. Disputes remain viable in soil, compost for at least 4 years.
Against the background of putrefactive damage, other diseases develop, spots are the gateway to other infections. The chemistry used by some farmers to disinfect harvested root crops gets into the flesh. It’s not safe to eat such potatoes.
Potato treatment for late blight
I know from personal experience that the best control measures are prevention. The main measures that reduce the risk of late blight infection:
- In late autumn, I always process all buckets, rakes, shovels, other equipment with a concentrated solution of furatsilina or potassium permanganate.
- In the spring, the seed is necessarily greened, we stand in the sun for several days. Corned beef, formed under the skin, is poisonous, such tubers rarely get sick. When planting, neighbors throw a handful of a mixture of wood ash and Phytosporin into a hole in a ratio of 4: 1. Agronomists advise to carry out fungicidal treatment: withstand tubers prepared for planting in a solution of drugs for up to 30 minutes.
- If the fungus appeared in the neighbors or on the greenhouse nightshade, you need to urgently process the planting of potatoes, then it will be too late.
- In the place where I plant tubers every year, I plant rye every autumn. In spring, the siderat sprouts, when digging, are planted in the soil. This is an effective way to improve the land, plus fertilizing. I noticed that as soon as you do not sow rye, potatoes are stored worse. No, no, but a tuber with rot.
I noticed that varietal seed material is less sick. Scientists have really learned to partition phytophthora-resistant varieties.
Fungicides safe for insects and animals
If the potato still gets sick, with small lesions I use herbal decoctions, mineral preparations, and folk remedies. When the defeat is strong, chemistry is indispensable. Spraying at the first sign of late blight. The multiplicity of treatments depends on weather conditions, the effectiveness of the composition.
Mineral compounds based on copper, the most popular is Bordeaux liquid. I dilute 100 g of copper sulfate in hot water, bring the volume of liquid to 10 l, add ½ cup of chalk.
Copper chloride is contained in the preparations:
- Abiga Peak, it is a medium toxic compound;
- Oxychom, this is copper oxychloride and oxadixyl, a fairly poisonous remedy;
- Hom - pure chlorinated copper.
To work with mineral compounds it is advisable to use a respirator, wear gloves. Repeated treatments are carried out with an interval of 5-7 days, if it is not possible to defeat late blight the first time.
Biological preparations act on plants superficially and consist of microorganisms that develop on spores of pathogenic fungi. There are a lot of them, I will list those that I myself used in greenhouses for processing tomatoes and eggplants, I sprayed potato plantings: Gliokladin, Fitosporin or Fitosporin-M, Gamair, Alirin-B. Universal remedies against all types of fungi Trichodermin, Planriz, Rizoplan.
It is necessary to apply funds in the evening, when precipitation is not expected. I use dry powders in the morning, spray them on wet leaves until the dew has dried.
Processing with biological products is allowed to be carried out every three days.
Folk remedies are needed for the prevention of late blight, they increase the immunity of plants, create adverse conditions for the development of fungal diseases. It is useless to treat damaged bushes with them.
- Ash well dries the soil leaves. The best is from birch firewood. I don’t especially sift it when I scatter it with a scoop under the bushes. It is convenient to use a sieve for dusting.
- Whey and dairy products are effective for individual beds, large plantations cannot be processed with them. Expired kefir, whey or sour milk is diluted 1:10 with water.
- Tinder fungus - a mushroom growing on the trunks of deciduous trees, dried, crushed. Per liter of boiling water you need 100 g of mushroom. Insist the mixture for 3 hours, filter, pour into a spray bottle.
- Garlic infusion is done as follows: 100 g of slurry is poured into 10 liters of water, insisted for a day, then 50 ml of liquid soap is added. The odor from such processing lasts up to two days.
Chemical preparations must be diluted according to the instructions. The last processing of tops is done 3 weeks before harvesting, not later. It is a lot of means, each well helps. it
- Ditan-M-45;
- Efal;
- Ridomil;
- Bravo;
- Syngenta;
- Epin or Epin-plus;
- Thanos;
- Topaz.
This is not a complete list of chemicals. But it is better not to bring the landing to a serious defeat.
Phytophthora resistant potato varieties
In garden areas, it is recommended to grow varieties that have good late blight resistance.
Early ripe varieties that are harvested in August before the autumn rains:
- Spring is white - with a light skin, tubers are rounded, 80-140 grams in size;
- Spring is pink - oval, with red eyes, the average size of potatoes is 135 g;
- Bullfinch - with tubers up to 90 g, resistant to lying, suitable for long-term storage;
- Desiree - with a pink skin, the flesh is yellowish;
- Polish lotus - oval-rounded light tubers 90-135 g in size, creamy flesh.
Early grades:
- Snow White - resistant to many diseases, well digested
- Fairy tale - light with pink spots at the eyes, appreciated for taste, medium-sized tubers;
- Sorcerer Ii - characterized by productivity, medium sized tubers;
- Rainbow - with oval tubers up to 150 g, appreciated for taste, keeping quality;
- Santa is rounded with light skin, yellowish flesh.
Late varieties:
- Temp - oval large tubers with a light skin;
- Blueness - rounded with a mesh skin, white flesh;
- Asterix - with a purple skin, light flesh;
- The gull is pink, oval tubers, light yellow flesh.
She noticed that early ripe varieties get sick much less often, as they fall ill before favorable conditions on late blight. But storing them for a long time fails, in the spring the tubers will quickly become flabby. For laying for long-term storage, we grow late varieties Asterix and Golubizna. We collect them in separate bags.
