by There is nothing more offensive than having invested several months of work, and by the end of the season, instead of a harvest of juicy cucumbers, getting several dried-up bushes with crooked and inedible fruits. The reason for such an unpleasant outcome is cucumber rot. So let’s learn to cope with the disease!
Rotting of fruits, stems, and roots of cucumbers can be caused by various pathogenic fungi that enter the soil from contaminated compost, last year’s plant remains, dirty garden tools, or untreated greenhouse structures. Fungal spores can even be transmitted to plants with water during irrigation.
The sclerotinia fungus causes white rot, which affects the root system, stems, as well as the leaves and fruits of cucumbers, manifesting itself as a white fluffy coating on damaged areas. Infection with gray rot also occurs “thanks” to the harmful fungus, penetrating into plant tissues through wounds during mechanical damage to the vines and petioles.
One of the causative agents of root and stem rot is a fungus of the genus Fusarium, which can affect not only cucumbers, but also other garden crops (tomatoes, potatoes, beets). The disease is also provoked by fungi Pythium, Rhizoctonia, SclerotiniaPlants at any stage of development are susceptible to infection – from seedlings to adult bushes in the fruiting phase.
Causes of cucumber rot
Rots are dangerous for both young cucumber seedlings in containers and for adult bushes growing in a greenhouse or in open ground. In protected ground, such diseases occur more often, since it is difficult to ensure free air circulation in such conditions, and this is critical for the health of plants. There are other factors that increase the risk of infection of cucumber bushes with root and other types of rot:
- violations of the temperature regime: sharp temperature fluctuations during the day, overheating or prolonged cold spells below 13-15°C;
- high soil humidity (above 80%) and air (more than 90%), especially in combination with a decrease in temperature;
- lack of sunlight during the day;
- violations of agricultural technology: dense plantings, poor ventilation, watering with cold water, errors in the formation of bushes;
- high soil density and lack of oxygen access to the roots;
- insufficient soil cultivation before planting (lack of disinfection) and failure to observe crop rotation (accumulation of pathogens of pumpkin crops);
- unfavorable weather conditions for open ground plants (cold, damp summer).
Any of these factors (and most often several together) can provoke active reproduction of pathogenic microflora in the soil and plant tissues and, in the absence of proper treatment, lead to the death of plantings.
Symptoms of Root and Stem Rot
In order to take the necessary actions to save a cucumber plantation, it is necessary to recognize the disease in time. The first symptoms of root rot can easily be confused with signs of insufficient watering: in hot daytime hours, the leaves become sluggish and turn yellow, the vines hang down, as if from a lack of moisture. After watering, the condition of the plants does not improve – on the contrary, the above-ground part becomes weaker over time.
The stems of cucumber bushes begin to dry out and become thinner, the root collar becomes covered with brown spots, which eventually merge, then the collar becomes frayed and rots. The leaves die off, and the formed fruits grow underdeveloped, crooked and tasteless.
At an early stage, the disease is difficult to recognize – you need to carefully monitor the condition of the bushes. At the first signs of wilting, dig up the soil at the base of the stem and check the root collar. If you find brown spots, darkened or dried out areas of the stem – take immediate action.
If you see that something is wrong with your cucumber bushes, but you cannot establish a diagnosis with certainty, then as an emergency aid we offer you a detailed cucumber disease identifier, which clearly describes the symptoms and treatment algorithm for most ailments.
Prevention of cucumber rot
It is not easy to fight root rot – it is easier to prevent its occurrence. To do this, you should initially plant the bushes in well-warmed soil (not lower than 15 ° C) and not thicken the plantings – the distance between them should be 20-30 cm. As the vines grow, they must be properly formed, blinding the axils of the five lower leaves.
It is recommended to water cucumbers strictly according to the schedule and only with warm water, and maintain the temperature in the greenhouse in the range of 18-27°C. Do not get too carried away with nitrogen fertilizers – this also increases the likelihood of infection with fungal diseases.
To prevent root rot, experienced gardeners always disinfect the soil before sowing cucumbers or planting seedlings. 1-3 days before sowing, water the bed with a solution of bacterial fungicide Alirin-B or Gamair (dissolve 2 tablets of the preparation in 10 liters of water).
The seeds are pre-treated in a biofungicide solution (Fitosporin-M, Fitolavin, Baktofit, Sporobacterin), soaking for 2 to 6 hours. As the cucumber bushes grow, the lower parts of the stems are dusted with tobacco dust, chalk or wood ash, and the soil underneath is periodically watered with the same preparations that were used to prepare the seeds.
Treatment of root and stem rot of cucumbers
If prevention has not helped and the cucumber bushes have sadly “hung” their leaves, you should begin emergency rescue of the victims – at the very beginning of the disease, this can still be done.
When the first signs of root rot appear in seedlings, if the bushes look vigorous, and the dark spots on the root collar are small, the problem can be solved by transplanting and deepening into the soil to the level of a healthy stem. Usually, when the root collar thins and dries out, lateral roots begin to grow above it, which, when immersed in soil or water, will develop into a full-fledged root system. It will feed the plant in the future.
When transplanting such bushes, the hole must be watered with a solution of biofungicide based on trichoderma (Trichoplant, Trichocin) or hay bacillus (Alirin-B). To speed up the formation of a healthy root system, it is also worth watering the plants with any rooting agent (KorneStim, Kornevin, Ukorenit).
Even if young cucumber bushes have wilted due to lack of nutrition, they can still be revived by re-rooting them in a container with a solution of a root formation stimulator. The plant stem is cut above the damaged root collar and the lower leaves are removed, then the part with the emerging lateral roots is lowered into a glass of water. If flowers and ovaries have already appeared on the bushes, they should be torn off in order to direct all forces to the formation of the root system. After a week or two, the plant with formed roots can be planted in the garden bed.
Adult cucumber bushes affected by root rot are more difficult to cure, but this does not mean that all is lost. If preventive treatments with Fitosporin or Baktofit do not restrain the development of the disease, you can resort to the help of combined fungicides with a more powerful effect.
Previkur Energy and Consento show good efficiency. In addition to fungicidal activity against a large number of pathogens, these preparations have a pronounced growth-stimulating effect, accelerate the development of the root system, and increase immunity. Previkur Energy is used for watering plants under the root, Consento – for spraying during the entire growing season. The working solution is prepared according to the instructions, the treatment of diseased bushes is repeated twice with an interval of 10-14 days.
A borage that is severely damaged by rot must be removed from the area along with the root ball, and the hole formed after digging must be watered with a fungicide.
To protect cucumber plantings from rot as much as possible, you should take all possible preventive measures in advance. And you should start with choosing disease-resistant hybrids: Maysky F1, Benefit F1, Advance F1, Orlik F1, Fair F1, Valdai F1, Gypsy F1.
May your harvests be crispy!
