Gray Rot Squash

2024 Author: Gavin MacAdam | [email protected]. Last modified: 2023-12-16 13:38

Gray rot especially strongly affects squash peduncles and ovaries with flowers. The affected areas are covered with a very unpleasant bloom and quickly begin to rot. Accordingly, the yield of fruits on infected plants is sharply reduced. Most often, gray rot attacks zucchini when rainy and fairly cool weather sets in. In order to avoid significant crop losses, it is important to start in a timely manner to combat this ill-fated misfortune

A few words about the disease

When dry weather sets in, infected tissues turn brown and gradually die off. If the weather is humid enough, then the tissues of the zucchini begin to slick, and a gray bloom appears on them. Also, in the infected areas, you can observe the formation of sclerotia (small black dots). Rot quickly spreads over the fruits, sometimes covering them entirely.

The causative agent of zucchini gray rot is a pathogenic fungus that parasitizes growing crops in greenhouses or small-sized film shelters. Throughout the growing season, fungal spores are transferred from diseased flowers to healthy ones with the help of bees and other pollinating insects, which in turn contributes to the defeat of new plants. Also, spores of the fungus can be carried by water during irrigation and wind. And the pathogen overwinters mainly on the remains of affected vegetation. The ability of a harmful fungus to survive well is due to the fact that it actively feeds on dead plant residues and tolerates various unfavorable conditions quite easily: excessive humidity, excessive dryness, heat and frost.

In one season, the pathogenic fungus gives up to eleven to twelve generations of spores. Germinating in the tissues of the plants it attacks, it forms mycelium and new spores.

Thickened planting and watering with cold water are capable of provoking the development of gray rot of zucchini. And the most severe lesions are noted when the temperature is set from twenty-three to twenty-five degrees. If the temperature begins to decrease, the development of the fungus will slow down and the formation of spores will stop.

How to fight

In order to prevent gray rot when growing zucchini, it is recommended to follow the rules of crop rotation: crops in crop rotation must be alternated, returning the zucchini to their previous sites no earlier than two or three years later. The remains of plants must be promptly removed from the sites. It is also recommended to periodically feed the growing zucchini with phosphorus fertilizers. Autumn digging of the soil will also do a good job.

Foliar feeding of zucchini will bring a lot of benefits. It is very simple to prepare a solution for their implementation: 10 g of urea, 2 g of copper sulfate and 1 g of zinc sulfate are dissolved in ten liters of water.

If the zucchini plantings begin to grow rapidly and thicken strongly, then cut out about a third of their leaves. First of all, they try to get rid of the largest and oldest leaves. Such a measure will help ensure better ventilation of the plants.

If infected ovaries and drying flowers are found, they must be removed in a timely manner, and the infected soil in greenhouses must be promptly replaced.

At the first signs of the development of an unfortunate misfortune, watering should be reduced and the growing crops should be sprayed with a copper solution. To prepare such a solution, a tablespoon of polycarbacin or copper oxychloride (50%) is diluted in ten liters of water. About half a liter of solution is consumed for each plant.

Also, plants are sprayed with a solution of chalk and copper sulfate (2: 1) and a special fungicide "Ronilan". This fungicide contains in its composition a poison that kills parasitic fungi - it not only kills fungal spores, but also inhibits their further germination, and also stops the growth of fungal mycelium. However, most often this tool is used indoors.