Content
- 1 Do cucumbers suffer from late blight?
- 2 Description and photo of late blight
- 3 Reasons for appearance
- 4 How dangerous is the disease?
- 5 Methods for treating late blight on cucumbers
- 6 Soil treatment after harvest
- 7 Is it possible to eat infected cucumbers?
- 8 Preventive measures
- 9 Cucumber varieties resistant to late blight
- 10 Conclusion
Late blight on cucumbers is a fungal disease that affects other crops, trees and even indoor plants. The pathogen is harmful and adapts well to different climatic conditions. Without proper prevention and timely treatment of infected plantings, you can lose your harvest.
Do cucumbers suffer from late blight?
Most often, late blight affects members of the Solanaceae family, but it can also infect other crops. Cucumbers are no exception.
Description and photo of late blight
The disease is caused by the fungus-like protists Phytophthora. About a hundred species of this pathogen have already been described, but it is believed that there are many more undiscovered species.
The photo shows one of the signs of late blight in cucumbers - yellow leaves. First, small brownish-brown spots appear on them and the stems, surrounded by a dark green border.Then the leaves curl, turn yellow and fall off. Other signs indicate late blight of cucumbers:
- growth slowdown;
- black stains on stems;
- white coating on the underside of leaves, especially in wet weather;
- cessation of ovary formation;
- on the fruits there are soft, slightly depressed spots of a brownish color, their gradual growth, the spread of rotting;
- browning of the bush;
- unpleasant odor from rotting areas.
Late blight on cucumbers usually appears in mid-July. The most favorable conditions for it are temperatures of 10-25 °C and high humidity (from 75%).
The source of cucumber late blight can be contaminated plant residues, compost
Reasons for appearance
The source of late blight infection in cucumbers is zoospores. They are carried by the wind, and during watering and precipitation they fall into the soil. The following factors contribute to late blight on cucumbers:
- presence of mechanical damage on plants;
- poor-quality seed material;
- thickening of plantings;
- weeds;
- constant soil and air humidity, including due to swampiness, excessive shading, lack of ventilation of the greenhouse;
- increased lime content in the soil;
- weakened immunity, including due to lack of fertilizers, improper care;
- depleted soil;
- sudden daily temperature changes.
How dangerous is the disease?
Late blight is dangerous for plants because it completely destroys them, leading to death. The fungus quickly spreads over long distances, affects other plantings, and infects the ground.The pathogen overwinters well in the soil and adapts well to climatic conditions.
Methods for treating late blight on cucumbers
To combat cucumber late blight, chemical and biological products and improvised means are used. Treatments are carried out in dry, windless weather.
Chemicals
The range of chemicals for combating cucumber late blight is extensive. The most effective options are:
- Ridomil Gold. For cucumbers in open ground, dissolve 30 g of fungicide in 10 liters of water.
Treatment against late blight is carried out four times every 1.5-2 weeks
- Previkur Energy. Prepare a solution of 0.15%, spend 20 liters per hundred square meters.
Cucumbers are watered at the root up to five times every two weeks.
- Home. 40 g per 10 liters of water, 3 liters per hundred square meters.
Cucumbers are sprayed against late blight three times every 1-2 weeks
- Quadris. Per hundred square meters, a package of the drug is 6 ml per 5 liters of water.
Repeated spraying after 1-1.5 weeks
- Oksikhom. 15-20 g per 10-liter bucket of water, enough for a hundred square meters.
Cucumbers are treated against late blight three times with an interval of 1-1.5 weeks, the last time can be five days before harvest
- Ordan. 25 g of the drug is dissolved in 5 liters of water (8 liters for closed ground) and consumed per hundred square meters.
Spray cucumbers against late blight three times every 1-1.5 weeks
- Cuproxat. 40 ml in 5 liters of water per hundred square meters.
Three treatments are carried out with an interval of eight days, 20 days before harvest.
- Medex-M. For late blight of cucumbers, dilute 100 g of fungicide in 10 liters of water and use it per hundred square meters.
Spray the plantings four times, a maximum of three weeks before harvesting.
- Antracol. Dissolve 15 ml in 10 liters of water per hundred square meters.
Cucumbers are treated with Antracol up to three times
- Bordeaux mixture. Both powders are diluted separately, the volume is adjusted to 5 liters, and mixed.
Cucumbers are sprayed three times every two weeks
Biological methods
Biological preparations mean environmental friendliness and maximum safety for people, animals, and insects. They are highly effective, act selectively and can be used throughout the growing season, even a few days before harvest.
The following biological preparations help against cucumber late blight:
- Fitolavin. 2 ml of the drug is diluted in 1 liter of water. This volume is enough for 10 m².
Cucumbers can be harvested two days after processing
- Fitosporin-M. 10 g of biofungicide are diluted in 5 liters of water and used for 50 m². The treatment is repeated three times with an interval of 1.5-2 weeks.
Fitosporin-M has no waiting period - cucumbers can be removed and consumed on the same day
- Trichodermin. 20 g of the drug is diluted in 10 liters of water. This volume is enough for 20 m².
Trichodermin should not be combined with chemical fungicides or mineral fertilizers
- Alirin-B. Cucumbers are sprayed three times, dissolving 5-10 tablets in 10 liters of water.
Alirin-B is effective in combination with other biofungicides - Gamair and Glyocladin
Treatment of late blight on cucumbers with folk remedies
Late blight of cucumbers at an early stage can be overcome with folk remedies. They are also effective for prevention. There are many processing options:
- Soap-garlic infusion. Grind 0.2 kg of peeled cloves, add 10 liters of water, leave for four days, filter, add 25 ml of liquid soap. The plantings are treated 3-4 times every 1.5 weeks.
- Garlic-manganese infusion. Grind 0.1 kg of garlic (cloves, arrows), pour a glass of water for a day, filter, add 2 g of potassium permanganate and 10 liters of water. Spray at intervals of 1.5-2 weeks.
- Milk-iodide mixture. Pour a liter of milk into 9 liters of water, mix thoroughly, add 30 drops of iodine. You can use kefir.
- Soap-ash infusion. 0.5 kg of ash is poured with water (10 l) for three days. The infusion is stirred periodically. Then add 20 liters of water and 40 g of laundry soap. Spray three times.
- Yeast infusion with iodine. 100 g of fresh product is poured into 10 liters of water per day, and 30 ml of iodine is added.
- Furacilin. For late blight on cucumbers in a greenhouse or open ground, add a tablet of the drug to each liter of water, dissolve and spray.
The spread of late blight is facilitated by rainy weather, fog, and dew.
Soil treatment after harvest
Phytophthora is extremely viable and infects the ground. To stop the spread of the pathogen and protect future plantings, the soil after harvesting is treated as follows:
- Remove all plant debris. This applies not only to cucumbers, but also to weeds.
- Dig the soil deeply.
- Spray the area with fungicide - Fitosporin-M, TrichoPlant, Bordeaux mixture, copper sulfate.
It is recommended to carry out such soil treatment against late blight in the spring before sowing. The soil for seedlings can also be calcined or steamed.
Is it possible to eat infected cucumbers?
So far, not a single scientific study confirms or disproves that cucumbers affected by late blight are safe for humans. They are not recommended for consumption for the following reasons:
- the exact effect on the human body is unknown;
- there is a risk of an allergic reaction;
- the disease causes a process of decay, which changes the taste and aroma of the fruit, depriving them of valuable elements.
It is not recommended to use cucumbers infected with late blight for canning, even if you cut off the damaged parts. There is a risk of increased acidity, which promotes the growth of pathogenic microorganisms.
Preventive measures
It is easier to prevent any problem than to fight it. To prevent late blight in cucumbers, the following measures are taken:
- Treat seeds with fungicides before sowing; do not use material from infected fruits.
- Follow the recommended planting pattern for a particular cucumber variety, excluding thickening.
- Regularly weed the beds and destroy plant debris.
- Do not plant cucumbers next to nightshades, and when sowing after them, carefully prepare the soil.
- Mulch the beds.
- Ensure air permeability of the soil by regular loosening.
- Apply fertilizers in a timely and competent manner. Use nitrogen in moderation, maintain a balance of copper, potassium, and phosphorus.
- Avoid moisture stagnation and ensure moderate watering of cucumbers. The best method is sprinkling.
- Ventilate greenhouses regularly.
- Already a few days after planting in the ground, begin preventive treatment with fungicides.
Cucumber varieties resistant to late blight
One method of reducing the risk of late blight is to plant varieties that are resistant to the disease. These cucumbers have the best immunity:
- Adam;
- Benefit;
- Aquarius;
- Hector;
- Delpina;
- Lancaster;
- Tom Thumb;
- Octopus;
- Diva.
Even good immunity to fungal diseases does not completely exclude them, so it is important to follow preventive measures
Conclusion
Late blight on cucumbers without timely treatment can destroy the crop. The disease spreads quickly and over long distances, affects other crops, and contaminates the soil. Late blight can be combated with chemical and biological preparations, folk remedies, and competent agrotechnical measures.
