What to do with bacteriosis of cucumbers - treatment with effective methods

The disease known as cucumber bacteriosis has a second name - angular leaf spot (due to the characteristic shape of the spots). Particular harmfulness of the pathogen is observed during the period of prolonged rains when growing crops in the open field, as well as at high humidity and low air temperatures in the greenhouse. With a large-scale infection of plantings, yield losses reach 50%.

In the article we will talk about bacteriosis of cucumbers, the causes of the disease, methods of its treatment and prevention.

What is bacteriosis of cucumbers

Bacteriosis is a bacterial disease caused by the pathogen P. syringae pv. lachrymans... The gram-negative bacterium resembles a stick with rounded ends, does not form spores, and has flagella. The size of the pathogen is 0.8 x 1.0–2.0 microns.

Distinctive feature of bacteria - the ability to form protective capsules, which ensure its increased survival in an unfavorable environment.

The pathogen enters plant tissues through small wounds and leads to necrotic lesions. The incubation period is 4-5 days.

Weak seedlings with few flowers appear from infected seed material... Low-quality cucumbers are formed on the plants. The pathogen spreads from cotyledonous leaves to true ones in the form of single necrosis.

Bacteria develop only on plant tissues. On rotten weeds, they remain active for a long period, and die in the soil.

The photo shows plants and fruits affected by bacteriosis.

Symptoms

Signs of corner spotting:

• small weeping light brown spots on cotyledons;
• yellowing of the leaf surface;
• necrosis on greenery;
• deformation of the cotyledons;
• death of seedlings in the ground;
• sticky, cloudy yellow drops on the back of the leaves (exudate), which, as they dry, turn into brown spherical drops;
• wilting of leaves;
• perforation of dry areas;
• dying off of plant tissues;
• shallow, rounded ulcers on fruits;
• curvature of the shape of cucumbers;
• the appearance of a cloudy liquid from ulcers during the period of prolonged rains;
• rot inside the fruit.

Harm to plants and humans

The danger of bacteriosis in cucumbers is the loss of yield... Infection of plants leads to a delay in the growth of cucumber bushes, a decrease in fruit formation, a deterioration in the marketability and taste of cucumbers. The yield loss reaches 50%, since the infected cucumbers do not enter the stage of biological ripeness.

Bacteriosis leads to partial or complete death of the bushes... Often, the disease is accompanied by brown spotting (cladosporia), increasing the negative impact on the culture. There is scientific evidence that conidia (immobile spores) of Cladosporium cucumerinum adhere to droplets of dried exudate and spread through the air.

Cucumber bacteriosis harmless to humans, however, diseased fruits are not recommended to be eaten... In any case, this does not make sense, because cucumbers lose their attractive appearance and taste.

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Causes of bacteriosis of cucumbers and favorable conditions for its development

The rapid spread of the pathogen on the site is facilitated by:

• temperature;
• humidity;
• priming;
• seeds.

The main source of infection is seeds harvested from infected cucumbers... The bacteria are active on the surface of the seed and under the shell. The pathogen remains viable for about 20 months.

Mass infection of plantings occurs in an enclosed space, for example, in plastic greenhouses. In an open area, bacteria are carried by streams of air, water, and by humans in the process of caring for plants.

Active reproduction of bacteria begins at a temperature of + 19 ... + 25 ° С... The causative agents of the disease are spread not only by air, but also through the soil. An excess of nitrates is a favorable environment for the development of colonies. The bacteria feed on nitrates. As a result, nitrites are formed, which accumulate in the upper soil layer.

Increasing air humidity up to 70% and maintaining this indicator within 2-3 weeks increases the risk of plant infection with bacteriosis manifold.

Treatment methods

Treatment of plants infected with the pathogen P. syringae pv. lachrymans., comes down to pre-planting seed treatment, spraying plants with chemicals during mass infection, using folk remedies for irrigating young foliage.

Chemical treatment

Disinfection of seeds is carried out using:

• fungicide "Apron XL" - 2.5 ml / kg;
• mineral 0.03% solution with potassium permanganate, zinc, copper, iron;
• solution of 0.02% zinc sulfate for 24 hours.

Therapeutic sprays are carried out when the first symptoms of the disease appear, using fungicides with bacteriostatic and bactericidal action:

• Median Extra - 2–2.5 l / ha;
• Infinito - 1.2-1.6 l / ha;
• "Acrobat MC" - 2 kg / ha;
• Metaxil - 2.5 kg / ha;
• Ridomil Gold - 2.5 kg / ha;
• "Quadris" - 0.6 l / ha;
• "Previkur" - 2 l / ha;
• Fital - 2–2.5 l / ha;
• "Alett" - 2 kg / ha;
• "Plant doctor" - 10-25 g / 5-8 liters of water;
• "Etafol" - 10–20 g / 10 l of water.

They are highly effective against bacteriosis of cucumbers preparations with copper:

• "HOM", "Oxykhom" - 40 g / 10 l, 1 l per 10 m²;
• copper sulfate - 100 g / 10 l of water;
• Ordan - 2.5–3 kg / ha;
• Kurzat R 44 - 3 kg / ha.

Often, a single spraying of the plantings is enough... Re-processing is carried out if necessary, observing the dosage and protective measures for the skin, eyes and respiratory organs.

Biologicals

To prevent bacteriosis of cucumbers, the seeds are soaked in biologics:

• "Agat 25-K" - 9 g / kg;
• "Pseudobacterin-2" - 0.1 l / kg;
• "Phytocide" - 2.5 ml / kg.

Hay stick products are highly effective.... Their advantage lies in their safety for human health and the environment. The bacterium Bacillus subtilis (Bacillus subtilis) inhibits the vital activity of many fungi and bacteria in the early stages of disease.

Treatment with drugs stimulates plant growth, reduces the time of seed germination, increases the yield by 20-30%. After therapeutic and prophylactic spraying, fruits can be eaten immediately.

Reference. Preparations with hay bacillus have a short duration of action on pathogens and lose their medicinal properties in the air. Therefore, treatments are carried out 4-5 times during the growing season.

The most effective biological products:

• Alirin-B;
• "Gamair";
• "Baktofit";
• «Fitosporin-M»;
• "PhytoDoctor".

Hay stick products are available at any gardening store, but they are easy to make yourself from dead hay, water, and chalk.

Cooking technology:

1. Spread out fresh hay or hay dust in the shade and spray it with water 2-3 times a week.
2. After 3 weeks, remove mold-free dust and chop finely.
3. To prepare the mother culture, take 1 tsp. crushed chalk, 100 g of hay, pour 1 liter of water, put on low heat and boil for 15–20 minutes. This allows you to kill all pathogenic microflora, except for hay bacillus, which is not afraid of boiling temperature. The broth is left to infuse in a warm place for 3-4 days to increase the number of bacteria. The appearance of a film on the surface signals the readiness of the product.
4. To prepare the infusion, take 1 kg of hay, 5 tbsp. l. lime, mother culture and pour 5 liters of water.Cover with a lid and leave for 3-4 days in a warm place.

There is an easier way to create a favorable environment for the development of hay sticks. - mulching the beds with hay. Dark and humid environments, moderate temperatures, and decomposing organic matter contribute to an increase in the bacterial population.

Read also:

What to do if cucumber leaves turn yellow

Why do rusty spots appear on cucumber leaves

Folk remedies

For the treatment of young shoots and plants that have entered fruiting, use products based on onion peel or boric acid:

1. A clean one-liter jar is filled with onion husks and filled to the brim with warm clean water. Leave to stand in a warm place for 48 hours. Then the infusion is poured into a separate container, the husk is squeezed out and the liquid is filtered through cheesecloth. To prepare the working solution, the infusion is diluted with water in a ratio of 1: 5. Spraying is carried out in the evening, before sunset. The frequency of treatments is 1 time in 10 days until the complete disappearance of the disease.
2. Dissolve 1 tsp in 10 liters of water. boric alcohol and brilliant green. The liquid is thoroughly stirred, used for processing cucumbers once every 20 days until the bacteriosis completely disappears.

Destruction of infected plants

In the case of a large-scale spread of the disease and the absence of the expected result treatment, diseased plants are removed by the root, removed from the site and burned. Then a deep digging of the soil is carried out - the infected plant residues will rot until the next season, and the pathogen will die from the cold.

Preventive measures

Measures to prevent infection of cucumbers with bacteriosis:

• planting plants in illuminated areas - the bacterium dies at temperatures above + 35 ° C within an hour;
• growing crops on a trellis;
• weeding and loosening of the beds;
• selection of varieties resistant to disease;
• disinfection of seeds before sowing for seedlings;
• organic fertilizing - compost and humus 1 time in 2 weeks;
• feeding with minerals - superphosphate, urea, potassium salt once every 2 weeks;
• collection of seeds from healthy fruits;
• cleaning plant residues;
• crop rotation;
• decrease in humidity up to 65% when growing crops in a greenhouse;
• disinfection of greenhouses and greenhouses with bactericidal solutions;
• spraying plantings with copper preparations.

Tips from experienced gardeners

Cucumber bacteriosis is one of the common diseases, which almost every gardener has to face.

On thematic forums farmers share tips on disease prevention and treatment:

1. Choose your cucumber planting site carefully. It is important that it is illuminated by the sun from all directions.
2. Tie the lashes to the trellis. This will create additional aeration of the landings.
3. Use clean water at room temperature for irrigation.
4. Observe the crop rotation. If cucumbers suffered from bacteriosis last season, choose another site for planting, for example, after legumes.
5. Choose varieties and hybrids with relative resistance to the pathogen (Nezhensky, Competitor, Far East, Octopus F1, Lesha F1, Masha F1).

Conclusion

The causative agent of cucumber bacteriosis remains viable for about 20 months. In the fight against the pathogen, infection prevention plays an important role. Healthy and vigorous plants are less susceptible to disease than weakened bushes.

Presowing seed treatment, periodic spraying of plantings with copper-containing agents and biological products, fertilizing with organic matter and minerals will preserve the health of the plant. In case of mass infection, heavy artillery is used - chemical preparations (Median Extra, Infinito, Acrobat MC, Metaxil, Ridomil Gold, Quadris, Previkur).