Treatment and prevention of late blight of cucumbers

Cucumbers

Late blight is a disease caused by the growth of the Phytophthora fungus. Fungal spores penetrate the plant, and when they accumulate in large numbers, the vegetable crop is damaged. Late blight on cucumbers spreads throughout the plot, infecting healthy plants. When the first signs of the disease are detected, action must be taken: chemicals and folk remedies can help eliminate late blight.

How to recognize the disease and causes of late blight

The disease spreads quickly from a diseased plant to a healthy one, with wind carrying fungal spores over long distances. Phytophthora infections occur when infected cucumbers and plant fragments are present in the garden, or when infected fruit is stored. Weakened crops are most susceptible. Causes of the disease:

use of infected planting material;
excess lime in the soil;
high humidity, overwatering;
dense plantings;
weather conditions: fog, sharp temperature changes during the day;
the ventilation regime in the greenhouse is not observed;
cucumbers grow in a shaded area.

Signs of late blight often appear towards the end of summer. In the initial stages of the disease, leaves begin to discolor and curl. As the disease progresses, fruit buds stop forming, and the plant stops growing and developing. Fruit begins to rot.

The area starts to smell of rot, weakened plants attract harmful insectsThe fungus multiplies on the leaves and shoots of cucumbers, and the spores migrate to healthy plants, infecting the soil. Cucumber crops are susceptible to fungal and viral diseases.

Important!

The most favorable conditions for fungus are a temperature range of +10…+25ºС, humidity from 75%.

Methods of plant treatment

Treatment is carried out in the early stages of fungal development. If one or two infected plants are detected, they should be burned away from the garden plot. Folk remedies are suitable for disease prevention; these recipes are effective if sprayed regularly. Chemical treatments should be carried out at the first signs of fungal disease.

Chemicals

Chemicals are used during the inflorescence formation stage of cucumber plants. These preparations are used prophylactically and to treat advanced fungal infections. Sprays are used to strengthen the plants' immune system and resist infection. To preserve the harvest, it's important to know how to treat cucumbers against late blight.

Name	The amount of active substance per 10 liters of water	Efficiency, method of application
Bordeaux mixture (0.5%)	60 ml – for the first treatment, 50 ml – for the second	2 sprayings are carried out with an interval of 15 days.
Copper sulfate	2 tbsp	They process the seedlings and soil, and water the holes.
Barrier	220 ml	Strengthens the immunity of vegetable crops and helps reduce nitrate levels. Improves plant stress resistance. The product is used to prevent late blight.
Hom, Oxyhom	20 g	A systemic fungicide that inhibits fungal growth and development. Apply during the growing season, with the last application 20 days before harvest.
Barrier	200 ml	The product is used to protect seeds, seedlings, and mature plants. Two treatments, 20 days apart, will help combat late blight.
Topaz	2 ml	The chemical inhibits the growth of fungal spores. Spraying is carried out during the growing season.
Trichopolum, Metronidazole	1 tablet	Irrigate the plant and water the roots. Cucumbers are treated three times during the growing season.

Spraying cucumbers is recommended in calm, dry weather. It's best to do this early in the morning or late in the evening. Chemicals are toxic, so wear protective equipment for eyes, respiratory system, and skin. Any remaining solution should be discarded; the liquid cannot be stored.

Traditional methods

Homemade remedies are environmentally friendly methods for combating fungus. They are suitable for preventing late blight but are not effective in cases of extensive infestation. Homemade decoctions can be used at any stage of plant growth and development; for maximum effectiveness, ensure consistent application frequency.

Important!

If weather conditions permit, and it's a hot, dry summer, folk remedies are sufficient for disease prevention. Fungal spores are killed by sunlight, stopping fungal growth.

Name of the solution	How to cook	Processing frequency
Garlic	Crush 100 g of garlic cloves and leaves, add 10 liters of hot water. Let it steep for 24 hours, then strain. Add 2 g of potassium permanganate to the solution before use.	The first treatment is before the ovaries form, the second is after 10 days. The cucumbers should then be treated after 2 weeks.
Saline	For 10 liters of water – 200 g of salt	Use at the first sign of disease. Salt creates a protective layer that prevents fungal infections.
Kefir	Add 1 liter of kefir or whey to a bucket of water. Let it steep for 2 days.	The first treatment is carried out after planting the seedlings in open ground. To prevent late blight, spraying is carried out every two weeks.
Yeast	For 10 liters of liquid, add 100 g of yeast. Let the spray solution sit for 24 hours, and add 10 drops of iodine before use.	Preventive measures are carried out as needed.
Ash	Add 0.5 kg of ash to a bucket of water and let it sit for 3 days. Add grated laundry soap before use.	3-5 times per season
Acid	For 10 liters of liquid – 1 teaspoon of powder	As needed

Copper piercings are also used to protect plants. Cut the wire into 3-cm pieces and pierce the plant stem. The piercing is done at a height of 10 cm, and the ends of the metal object are bent. This method has been proven effective – copper ions rise through the plant sap, providing the cucumbers with beneficial micronutrients.

Soil treatment

Agronomic, chemical, and biological methods are used to cultivate the soil. Fungal spores survive in the soil for several years, so cucumber planting sites must be rotated annually. If the site previously contained vegetable crops infected with late blight, soil preparation begins in the fall before planting. Preparatory work includes:

watering with a solution of copper sulfate;
irrigation with a weak solution of potassium permanganate (2 g of active substance per 1 bucket of water);
scattering wood ash over the area;
land cultivation Fitosporin (100 g per 10 l of liquid).

Baikal EM-1 and EM-5 are used as biological treatments. These preparations are diluted according to the instructions after tilling the soil. This procedure is carried out in late fall and early spring. Using several soil treatment methods can enhance the protective function. It is recommended to fertilize the soil with compost 1-2 weeks before planting.

Important!

Green manure crops such as rapeseed and mustard will help improve the soil.

Disease prevention

Preventative measures are aimed at maintaining the required temperature and humidity levels. To protect cucumbers from late blight, avoid overfeeding with mineral fertilizers and organic matter. It is essential to follow proper plant care guidelines: timely watering, weeding, and disinfecting tools.

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Before planting, prepare the greenhouse: fumigate with smoke and treat the structure with Fitosporin. Install a thermometer to monitor the temperature in the greenhouse. If the temperature fluctuates significantly between night and day, install a low-heat source.

When planting seedlings, it is necessary to observe crop rotation and follow the rules:

Choose cucumber varieties that are resistant to late blight.
Don't plant cucumbers in the same spot for the next season. Apply potassium-phosphorus fertilizer to the soil before planting.
If late blight is detected, remove damaged leaves and burn them away from the garden plot.
Planting onions and garlic next to cucumber beds will help protect against late blight.
If late blight appeared - cover the beds with waterproof film during the rainy season, limit watering.
Mulching the beds will help prevent fungal infection and will reduce the growth of weeds.

A comprehensive approach will help protect cucumber crops from late blight. Crop rotation, proper vegetable care, and fertilization will help strengthen the plants' immunity and prevent late blight.