In the spring, every gardener thinks about how to protect the future crop of cucumbers from insulting losses.
Everyone knows that cucumbers love the heat. However, many beginner growers do not take into account the fact that for the successful cultivation of a vegetable it is equally important to maintain an optimal level of humidity in the greenhouse and in the open garden.
Anthracnose of cucumbers is a formidable fungal disease that can cause the premature death of cucumber lashes and cause a serious blow to yield.
Cucumber anthracnose causes a fungus called Colletotrichum orbiculare, which also infects plants like cantaloupe and watermelon. But pumpkin and other types of melons rarely suffer from this disease.
In greenhouses, greenhouses, and film shelters, the first symptoms of anthracnose appear in the spring on shoots. In the open ground, this disease raises its head only in the middle of summer.
How to detect anthracnose
Usually, the leaves of plants are the first to be damaged. Weaky areas form on them, which then turn into small rounded spots of pale yellow color. Over time, places of damage expand, turn brown, growing to 2-3 centimeters in diameter.
When infected with anthracnose, petioles and shoots form oblong or oval light brown sores, which, with increased humidity, become covered with pink spores. Ulcers often encircle the stem and cause the upper parts of the damaged shoots to wilt.
As it ripens, the disease also affects the fruit. On the fruits, it initially looks like round moist spots, which gradually become wider and, as it were, are pressed into the tissue of the cucumbers. In particularly wet periods, colonies of yellowish-pink spores grow in such places. Fruits quickly tighten, rot, become bitter.
Cucumber seedlings are not protected from anthracnose damage if they are grown from infected seeds. In this case, wet, pale yellow or brownish necrotic spots-lesions develop on the cotyledonous leaves.
The spread of the disease to the roots of a cucumber plant causes its inevitable death.
Sources of infection and spread of anthracnose
In the off-season, the causative agent of anthracnose of cucumbers lives on seeds, in plant debris, and in the upper soil layer.
The incubation period is 3-6 days. Note that if the source of infection is seeds, seedlings of cucumbers will also be affected by this ailment. And, when planted in the open or protected ground, it will infect still healthy plants.
Anthracnose spores fly around a greenhouse or plot during periods of heavy rains when irrigated by sprinkling and in high winds. In addition, they are carried around the site by insects and on garden tools, if it was used to work on infected beds.
Two main factors contribute to the development of the disease:
- Preservation of elevated temperature – +22 … 27 degrees.
- High humidity in a greenhouse or greenhouse for a long time and regular formation of an aqueous film on the surface of cucumber leaves.
In some years, anthracnose causes significant damage to the greenhouse crop and greatly reduces the quality of the fruit.
Measures for the control and prevention of anthracnose cucumbers
Anthracnosis is an insidious disease that is difficult to treat. Therefore, it is more reasonable to prevent it than to treat it.
Such preventive measures include, but are not limited to:
- selection of varieties and hybrids resistant to this disease – Cascade, VIR 505, Surprise 66, Skvirsky F1, Phoenix F1, Intolerable 40;
- purchase of seeds and seedlings from trusted sellers;
- regular inspection of plants in the garden to identify early signs of anthracnose and timely removal of diseased leaflets from the bottom of the plants. This will not only limit the development of the disease but also improve air circulation in the garden ;
- if possible, avoid irrigation of cucumbers by sprinkling and do not water plants on cloudy days;
- at the end of the season, remove all cucumber tops from the site and burn it;
- observe a three-year crop rotation – return pumpkin crops to their former garden no more than once every three years.
The main source of anthracnose infection is cucumber seeds. Therefore, their quality
training is one of the most important preventive measures against the disease.
To cleanse the shell of cucumber seeds from pathogenic microflora, 3 simple methods are used:
- The classics of the genre are thermal disinfection of seeds in hot (+ 56-60 degrees) water for 5-6 hours. After this, be sure to hold the seeds in cold water for one to two minutes.
- Sterilization in a 1% solution of potassium permanganate for 20 minutes. To prepare such a solution, dissolve one teaspoon of this substance in 600 milliliters of water. After treatment, do not forget to thoroughly rinse the seeds under running water.
- Disinfection of cucumber seeds with natural fungicides. For example, mustard (1.5-2% aqueous solution for six hours), aloe juice (leave the leaves for 5-6 days in the refrigerator, squeeze the juice, dilute it with water in a 1: 1 ratio and keep the seeds in this solution for within 20-24 hours), alcohol tinctures of medicinal herbs for an hour, etc.
This article will tell you about all alternative methods of pre-sowing seed treatment.
With a high infectious background throughout the growing season, it is better to treat with a 1% Bordeaux mixture – 100 grams of copper sulfate and 100 grams of lime diluted in 10 liters of water, or copper chloroxide – 60 grams per 10 liters of water.
The last spraying is carried out no later than 5 days before the first harvest of the fruit.
A good effect in the fight against anthracnosis of cucumbers gives such a drug as Fundazole – 10 grams per 10 liters of water. However, any treatment with this agent should be discontinued 7 days before the collection of greenhouses.
In the prevention of a wide range of cucumber diseases, biologics such as Bactogen and Trichodermin have proven themselves well.
The first is bred in water according to the instructions and used for seed preparation, in the care of seedlings and plants in the garden, that is, at all stages of the growing cycle. The second is poured into the planting holes when planting seedlings at a rate of 10 grams per plant.