The development of plants and the appearance of the crop are often hindered not only by insect pests, but also by various diseases: powdery mildew, peronosporosis, rot, coccomitosis, anthracnose, rust, and many other fungal diseases.
In this article, we will talk about how to deal with powdery mildew and the treatment of downy mildew (overexposure).
Powdery mildew is one of the most common fungal diseases affecting pumpkin crops. Usually, it is found in greenhouses and hotbeds, but under favorable weather conditions (high air temperature and humidity) spreads quickly in open ground.
Peronosporosis affects cucumbers, melon, pumpkin, watermelon, as well as plants of the family Cactus. More often than other plants, parsley, parsnip, celery, dill, as well as cucumbers, zucchini, cabbage, peas, onions, and beets become infected with this disease.
Measures to Combat Powdery Mildew
As can be seen in the photo, powdery mildew is a white coating on the leaves and causes the plants to dry out. With severe damage, white spots also appear on the stem and fruits.
The rapid spread of powdery mildew in the protected ground is facilitated by sharp temperature fluctuations, drafts, watering plants with cold water. Powdery mildew quickly spreads in open ground with the onset of steady hot weather and with the appearance of dew.
Pathogens persist on plant debris and on weeds.
In open ground, cultivars resistant to powdery mildew are recommended. Plant residues, as well as diseased plants, should be burnt or buried in the soil to a depth of at least 40 cm. In autumn, the soil must be carefully dug up and the crop rotation must be observed, that is, to plant the plants in the same place no earlier than after 3 years.
One of the measures to combat powdery mildew is to lubricate the leaves and stems with the ground or colloidal sulfur with a cotton swab. Further, if necessary, plants should be treated with a suspension of colloidal sulfur or infusion of mullein.
In sheltered soil, it is also recommended to cultivate powdery mildew resistant varieties, once a year to remove and remove a layer of soil 3-5 cm thick. To prevent disease, the frames of greenhouses and hotbeds are greased with sulfur.
To prevent the disease, the temperature regime should be observed. The daytime temperature in the greenhouse should be 24–26 ° C during the day, and 20 ° C at night.
This fungal disease affects the leaves and stems of beans and peas, which turn yellow and dry. At the same time, powdery mildew consisting of fungal spores is clearly visible on the affected organs. The disease can persist for a long time on plant debris. The infection develops at an air temperature of 20-25 ° C and relative humidity of 70-80%. To protect legumes from powdery mildew, the sources of infection should be destroyed, as well as preventive measures, including the treatment of plants with sulfur preparations 2-3 times every 10-15 days, should be carried out.
How to Deal with Downy Mildew and Photos of Peronosporosis
Peronosporosis affects plant leaves. It develops both in closed and in open ground and often leads to the death of plants.
Pay attention to the photo of downy mildew – at first, it is oily spots on the leaves, which then turn into brown. On the underside, a purple coating of fungal spores is clearly visible. The causative agent can persist in soil and plant debris for 5-6 years. No varieties are resistant to the disease.
The spread of peronosporosis is promoted by high humidity and air temperature, therefore, to protect the plants of protected soil, an optimal microclimate should be maintained. Humidity should be no higher than 80%, and air temperature at night not lower than 20-22 ° C. Powdery mildew can persist in the soil and on plant debris, so autumn soil digging should be carried out and plant debris burnt.
To protect pumpkin cultures from peronosporosis, they are sprayed with a 0.4% solution of copper chloride, a 0.4% solution of polycarbacin or Bordeaux liquid. To prepare it, 100 g of lime and 100 g of copper sulfate are mixed with 10 l of water. Before planting in open ground, seedlings are recommended to be fed with ammonium nitrate.
When growing crops in greenhouses, it is important to prevent sudden temperature changes in them.
High humidity is also harmful to plants under the film.