Mold is a dangerous disease that affects all the aerial parts of the plant, resulting in lower yields. About the causes of the appearance of black mold on cucumbers and how to deal with the disease, read below.
Did you know? The foot of the Himalayan mountains is the birthplace of cucumbers. In this area, the vegetable is still growing in the wild.
Disease Description
Black mold (leaf “burn”) is a fungal disease that spreads over the entire surface of the plant. Leafy plates and stems are covered with a soot coating, which is a conidial spore of black mold, due to which the ailment penetrates the plant tissue. It has a dark-color series, with a purple tint.
First, the disease affects the old leaf plates, after the appearance of plaque, brown spots appear on their surface that do not have any peculiar shape, they can be: angular, round, irregular in shape. Over time, the spots merge into one, dry and spill out, forming sections of dead tissue with a diameter of 1.5 cm. A hole is formed at the spot where it is outlined by a brown rim.
Why does a black coating appear on cucumbers: the main reasons
The formation of mold is always the result of external factors, such as: humidity and high temperature. The main reasons for the appearance of plaque on the leaves of cucumbers, read below.
On the leaves
Black mold is most pronounced on the leaf plates of a culture grown in open ground. The appearance of soot spots on plant surfaces will be promoted by air temperature from + 20 ° С to + 27 ° С, which is the most optimal for the development of conidia. Under such conditions, the spore of the fungus will develop at a moisture content of even 50%.
The disease can attack the plant during its weakening, which occurs due to a sharp temperature difference of + 10 ° C at night and + 30 ° C in the daytime. The most common causes of the disease are also: improper care, consisting in poor disinfection of plant care products and poor seed treatment before sowing.
Important! Aphid invasion also contributes to «burns» leaves. The insect's vital product is a sticky coating left on the leaf plates, it becomes the cause of the development of pathogenic microflora and infection with the fungus.
On the cucumbers in the bank
If a black coating appears on the cucumbers in the bank - this means that the cooking technology was not followed when rolling. So we can observe that the parts of the vegetables protruding from the filling fluid inside the jar are dark in color. The blackening process occurs due to contact of the product with oxygen, which causes oxidation.
Cucumbers with a black coating on their surface are simply cut off at the site of damage.
Soot such as soot can be observed on the inside of the seaming lids and on the surface of the products in the jar, but it has nothing to do with mold - it is sulphurous iron. Such a plaque does not pose a threat to the body, it is simply gently erased from the lid.
On greenhouse cucumbers
On cucumbers grown in greenhouse conditions, a leaf burn appears due to increased humidity indoors. The cause of the disease also becomes the seeding of infected planting material.
This phenomenon most often occurs due to condensate that collects on the polyethylene coating of the greenhouse.
Poor plant care - one of the main provocateurs of mold formation: watering with cold water, use of non-disinfected tools for tillage and pruning, violation of the ventilation mode, all this causes the spread of fungal spores.
What to do and how to deal with plaque
If a sooty coating appears on the leaves of cucumbers, you must immediately begin to fight the ailment, without waiting for the symptoms to worsen. It is better to treat the disease using alternative methods that are safe for humans and plants. But, if the use of folk remedies does not bring the desired results, you should resort to treatment with insecticides.
Use of chemicals
Leaf burn treatment is performed in dry, calm weather. It is necessary to take a 3% solution of Bordeaux fluid (300 g per 10 liters of water) and spray the entire surface of the plant from the spray gun. Processing is carried out 2 times at weekly intervals.
If it is necessary to process cucumbers in greenhouse conditions, then the procedure is also performed.
Important! When cucumbers are infected with mold in a greenhouse, additional processing of the walls of the room is required, they are thoroughly washed with dust soap, and then treated with a light pink solution of potassium permanganate.
To treat the disease, you can also use the drug "Fitosporin-M", which is used in powder, liquid or paste form according to the instructions (1 part of the substance in 2 parts of water).
If the cause of the appearance of the fungus is an invasion of aphids, you can use drugs such as:
- "Aktara", which is prepared according to the instructions of 8 g of substance per 10 liters of water, the flow rate of the solution is 10 liters per 10 m²;
- Inta-vir is prepared from 2 tablets of the drug diluted in 10 liters of water, the substance consumption is 1.5 liters per 10 m².
The use of folk remedies
A soap solution, which is prepared according to the instructions, will perfectly cope with the ailment:
- Laundry soap 300 g grate.
- Heat water in an amount of 10 l to a temperature of + 45 ° C.
- Stir soap in water.
- Insist the solution during the day.
Irrigation is carried out within 2-3 days until the soot deposits have completely disappeared.
Did you know? Spikes are needed for cucumber to remove excess fluid, in extreme heat you can notice small droplets of water on them.
A solution with soda is prepared from: 100 g of soda, 100 g of liquid soap and 10 l of warm water. Cooking method:
- Heat the water to + 45 ° C.
- Dissolve soda in water, let it brew for 3 hours.
- Add liquid soap before spraying.
Irrigation is carried out 2 times a day for 2 days.
Disease prevention
In order to prevent the appearance of fungus on the plant, you must follow the rules for growing the plant and timely clean the area on which the culture is grown.
Prevention of black mold:
- after the end of the season, you need to dig the site to a depth of 30 cm;
- harvesting vegetation residues at the place of cultivation and burning them;
- soil disinfection before sowing seeds;
- seed disinfection;
- loosening of soil near the stem of the plant.
The reason for the appearance of black plaque on cucumbers can be a number of physical factors such as: improper care, the influence of weather conditions, non-observance of crop rotation. In the fight against the disease, you can use folk remedies and chemicals. But, it is best to carry out annual preventive measures to prevent the disease and thereby avoid loss of yield.
