It is very important to recognize in time that it is gray rot that threatens tomatoes, cucumbers, grapes, strawberries and immediately start agrotechnical saving measures. Gray rot, and in Latin Botrytis cinerea is a plant disease. It is caused by the fungus Botrytis cinerea. It can infect cultivated plants and flowers. If gray rot develops on root crops during storage, transportation, then it is called "kagatny rot".
The clinical picture of the manifestation of gray rot
Most often, infection occurs due to uncleared plant debris that are on the ground, in the soil. Infection occurs through dead areas of plant tissue, especially if the weather is humid.
Such conditions exist in protected ground. Therefore, the crops growing there are affected more often than similar ones in the open field. During the disease, leaves, flowers, stems, and fruits are affected. Usually, the disease first manifests itself on the lower old leaves, then spreads to the stem. Light brown dry spots appear here.
When the spores of the fungus reach the fruit, they first affect the stalks, then a gray spot is formed, which quickly grows and soon covers the entire fruit. It becomes watery with a gray fluff - conidial spores make themselves felt.
What crops are at risk of gray rot?
It can affect many types of plants, causing great damage:
Kagannoy rot of fruits threatens pumpkin, sugar beet.
Gray rot of grapes
This disease is the only one that accompanies the bush throughout the year, in the presence of favorable conditions for this disease. A harmful microorganism is especially dangerous during vaccination, since it affects not only the harvested cuttings, but also the site of vaccination. It can settle on both annual wood and green parts of the vine.
If the weather is damp and cold in spring, gray rot often covers young shoots and buds with its bloom, as a result of which they may die. This mushroom is dangerous for ridges and berries. Gray rot becomes the causative agent of vinegar rot if it appears during a period when the berries are not yet ripe. It is easy to recognize the disease on the fruits; when damaged, they first turn gray-brown, in wet weather a gray bloom appears on them. This can cause the bunch to turn into an unattractive lump. If dry weather is established, then the development of the disease is suspended, and the affected berries shrivel.
If you notice any of these signs on the vine, you need to take action immediately, but it is better to take preventive measures even before that. First of all, agrotechnical. It is necessary to form a high bole of the bush, provide it with a sufficient area of nutrition, and fight weeds. Do not apply large doses of nitrogen fertilizers, which lead to the formation of unstable, succulent tissues susceptible to the fungus. It is advisable to start removing the grape leaves below the bunches in early September. Since at this time they are no longer needed to feed the berries, but they contribute to the spread of fungal and other infections.
Previously, the bushes were sprayed with soap, but then it was found that even a high concentration of it does not help fight gray rot. The fight against the disease with the use of Bordeaux liquid is quite successful, but this remedy affects the quality of the berries, therefore it is better to refuse its use and spray the bushes with it only in early spring and late autumn after harvesting. Also earlier, preparations of the benzimidazole group were successfully used, but the soon emerging strains of gray rot showed their resistance to them. Moreover, having adapted to these drugs, they found useful substances for themselves and from this they began to develop even more strongly. Gray rot of grapes is defeated with Ronilan and Rovral. The first one needs to be diluted at a concentration of 0.1%, and the second at 0.075%. Fungicide "Teldor" is used against this disease. With the preparation diluted according to the instructions, make 1-3 sprays. The last time is 4 days before harvest. Against gray rot of grapes and some other crops, you can use drugs:
- Ridomil Gold MC;
- Topsin M;
Gray mold of cucumber
Its development and distribution is facilitated by a lack and excess of moisture, overfeeding with nitrogen, evening watering, as well as watering with cold water, a lack of important microelements, and sudden temperature changes. If cold weather sets in, the first signs of damage can usually be seen where the flowers attach to the stem. Insects transfer from flower to flower not only pollen, but also the spores of the fungus, thus contributing to its spread.
In order to prevent the appearance and development of this and other cucumber diseases, it is necessary to observe crop rotation, remove plant residues in time. It is better to water in the morning and always with warm water, and then the greenhouses and hotbeds need to be aired. If you find signs of gray rot on the lower leaves, trim them back. If they appear on the stems, these areas must be sprinkled with copper-chalk powder or lime. In case of severe damage to the stems, these places are carefully cut out, and then they are treated with these preparations. You can dilute copper sulfate with water to a concentration of 0.5%, let the cut sites dry, and then wipe them with this solution or sprinkle with crushed coal. Flowers affected by gray rot are best removed.
In order for the plant to be able to resist the disease, do foliar feeding. To do this, add 1 g of copper sulfate, 0.5 g of zinc sulfate, 5 g of urea to 5 liters of water. Infected stems are coated with an aqueous solution of the drug "Rovral" and a chalk mixture in a 1: 1 ratio. For the prevention and fight against gray mold on cucumbers, it is recommended to use the drug "Trichodermin". Euparen Multi has also proven itself well. They are treated every 2 weeks.
Gray rot of tomatoes
It is easy to recognize, it appears as light brown spots that first affect the lower leaves, then spread higher. On the stem, these spots can be small or large. Gray rot on mature fruits starts from the stalk. If you do not notice a small gray spot in time, then it will quickly spread throughout the fruit and destroy it. On young fruits, botrythia spotting may appear in the form of small spots with a white edging.
In addition to removing affected plants, observing crop rotation, it is possible to advise spraying damaged stems with Trichodermin. "Gamair" will also help against gray rot. To do this, you need to dilute 1 tablet in 1–1, 5 liters of water. Tomatoes should be sprayed at the beginning of budding and fruit formation, with an interval of 1-2 weeks. This drug will also help defeat late blight. Fitolavin has also proven itself well against gray rot. 20 milliliters of this preparation is diluted in 10 liters of water and the plants are sprayed 1-2 times with an interval of 7-10 days, 10 liters of solution is enough for 100 meters of planting. Besides tomatoes, cucumbers can also be processed with Fitolavin.
Gray rot of strawberry
It can lead to the death of a large part of the crop. Therefore, before planting strawberries, the prepared bed is covered with black cellophane, round holes are made in it with scissors and young bushes are planted. For prevention, you can spray them before flowering with "Fitosporin" or another drug that helps prevent gray rot.
When planting, the bushes do not need to be placed too often - you need to provide them with ventilation. If the berries do not touch the ground, then the harmful effect of the disease is reduced significantly. You can put planks under the berries, put sticks to the peduncles, tie them to them. Straw, sunflower husks, sawdust are placed under the bushes. This will also prevent the berries from coming into contact with the soil.
After the end of fruiting, you need to spray the bushes with Bordeaux liquid, diluting 2 teaspoons of this drug in one liter of water. The drug "Zircon" is useful for plants, it will help to strengthen the immune system, then it will be resistant to fungal diseases.
Fruits affected by gray rot must be collected and disposed of. For adherents of folk methods of combating diseases, the following recipe can be recommended: spray strawberry bushes with mustard infusion once a week. This must be done before flower stalks appear on the strawberries.
These are simple measures of prevention and control that will help to defeat gray rot on grapes, cucumbers, tomatoes, strawberries and other plants.
For more information on gray rot on cucumbers and how to combat this disease, see this video: