Contents
The appearance of white spots on the leaves of zucchini is an alarming symptom, indicating that the plant is affected by the disease. Of course, this state of the vegetable will please few people, especially considering the tendency of diseases to spread to all plants from neighboring beds in a matter of days. In order not to endanger the harvest and life of zucchini, you need to know how to deal with various diseases, how to prevent disease and, of course, how to quickly and effectively save plants.
What are these spots
White spots can have a different pathogenesis: become a symptom of a fungal disease or signal the impact of a harmful insect on a vegetable. You can identify such spots with the naked eye – they cover the leaf blade in abundance, creating a marble texture, less often spread to the stems of zucchini. Below is a list of the most common diseases and pests that leave such marks on the leaves.
spider mite
This insect is found in abundance in greenhouses and greenhouses. Having a small body size, only 0,4 mm, the spider mite can be missed on especially dense bushes. The tick has an elongated body, its eggs are round, greenish or whitish in color. Colonies of spider mites settle on the lower part of the leaf, rather quickly starting to braid the living part with a thin white cobweb.
Damaged leaves are covered with white dots, which eventually expand into spots of indefinite shape. Within a few days, the leaf turns yellow and then dies. If nothing is done, the plant will die. Spider mites are most active in June-August, when a consistently high air temperature is established, which they like, at this time they can also appear on the open ground. Ticks prefer to wait out the off-season under plant debris, in various crevices, frames or in the ground at a depth of 5-6 cm.
Video “Tips for growing zucchini”
Demonstrative video with recommendations for growing zucchini, which will help to avoid diseases.
Mučnistaâ rosa
One of the most common fungal diseases of cucurbits is powdery mildew. Spores of the fungus develop and parasitize on plant tissues, mainly leaves, in conditions of high humidity or with frequent dew. As soon as the weather becomes cloudy, rainy, and the thermometer drops to + 18 ° C – wait for the appearance of powdery mildew. One of the factors favorably influencing the spread of the disease is the oversaturation of the soil and plants with nitrogen fertilizers, without regular watering.
Round spots appear on the leaves, white or whitish-gray. After a few days, the spots increase in size, a little later they become covered with a powdery coating, which abundantly spreads throughout the entire leaf blade and stem. Infected leaves become lighter, up to a yellowish-white color, fade, subsequently die off. The stems lose their elasticity, become lethargic and brittle, often completely die off. If powdery mildew appeared on the plant during fruiting, then with a high probability the fruits will ripen ahead of time, but will lose their taste, acquiring a bitter or sour taste.
Powdery mildew spores are frost-resistant, hibernate on plant debris or in the upper layers of the soil. Often, perennial plants are chosen for wintering, which are not cut to the root in late autumn. It poses the greatest danger to plants in greenhouses.
Gray mold
Another fungal disease, the manifestation of which is whitish spots and dots on the leaves of zucchini, is gray rot. First of all, it affects the leaves and ovaries of zucchini, leading to their death. Dark spots appear on the plant, powdered with a whitish-gray bloom. After a few days, these spots become wet, soft, slimy, plaque begins to actively spread to neighboring plants along with pollen.
The trigger for the appearance of gray rot is sudden changes in air temperature, for example, at the end of May and August. It also encourages the development and spread of high humidity in the air and soil, since warm, moist air is ideal conditions for the life of the fungus. As in the case of powdery mildew, gray rot is very likely to choose plants with an excess of nitrogen, since it stimulates the development of the green mass of the crop, thickening of the bushes. Gray rot spores overwinter well on plant debris and in the upper layers of the soil, therefore they actively infect plants that have been planted in the same place for several years.
White mosaic
In terms of danger to the pumpkin family, the white mosaic occupies a leading position. The leaves of infected zucchini become covered with white and yellow spots, forming a mosaic pattern. Most often, over time, they fade to white, only the veins of the leaf remain green. The structure of the sheet does not change – it does not wither, does not deform, does not twist into a tube.
With a disease, plant growth stops, leaves and stems begin to shrink, and during fruiting, small deformed fruits with white stripes, sometimes with growths, are formed. The inhibition of knots and lashes of zucchini is noted, their fragility and fragility increase. White mosaic develops in conditions of sharp changes in air and soil temperatures. Causes the activity of the virus by watering with cold water, the temperature of which is much lower than the temperature of the earth. The disease is transmitted through the root system and juices – from an already infected to a healthy plant. In the risk zone, plants planted twice in a row in the same place, attacked by melon aphids or grown from seeds of diseased plants.
Methods of struggle
As you know, it is better to carry out prevention than to treat plants, but if you have not encountered the problem of spots on zucchini before, then it’s okay. Perhaps in the war against diseases you will lose a few plants, but save all the rest of the plantings. Spots on zucchini leaves are a symptom, let’s figure out what needs to be done to nullify them.
To drive the spider mite off the leaves, spray the beds every day with an infusion of onion peel or garlic. Insects do not really like such treatment, therefore, disturbed, they will stop actively eating vegetables. To prepare the husk infusion, pour 700 g of husk with ten liters of water, boil, let it brew for 6-8 hours, strain and proceed to the processing of plantings. For garlic infusion, you will need to grind 5-6 heads of garlic into gruel, pour them with four liters of hot water, let it brew for 2-4 hours, strain and apply.
Weed and thin out zucchini plantings regularly. Carry out regular top dressing to develop immunity in plants. Use chemicals, such as “Keltan” or “Isofen”.
Getting rid of powdery mildew on zucchini leaves will be more difficult. First, you’ll need to dig up squash leaves, weeds, and diseased plants around the beds or greenhouse. Then the remaining plants must be sprayed with fungicidal preparations, for example, use Isofen, Topsin-M or Topaz. To prevent the fungus from taking root, spray the plants with a solution of copper oxychloride.
To prepare it, mix 40 g of raw materials with ten liters of warm water. Be sure to transplant zucchini every year to a new place, maintain a stable temperature in greenhouses, and water the plants with warm water.
It is possible to expel gray rot from the beds only by complex measures: regular weeding, application of a complex of mineral and organic fertilizers, treatment with fungicides (Rovral, Bayleton). Treat diseased plants with whey, which is easy to prepare at home: dilute 1 liter of sour milk with 3 liters of warm water, mix thoroughly, let it brew for 3-4 hours, and then spray the zucchini. At the time of treatment, it is important to stop watering, remove all parts of the plant affected by the disease, and thin out the plantings.
To overcome the white mosaic is probably the most difficult thing – it is necessary to replace the infected soil with a new, disinfected and fertile one. It is necessary to take seeds from healthy plants, carefully process them before sowing. Weeding weeds, spraying plantings with infusion of onion peel or soapy water to drive away the virus carrier – aphids. Try to maintain a stable air temperature, water the plants with warm water. For almost all diseases of the pumpkin family, prevention and control methods are the same: do not water the plants with cold water, do not feed them with nitrogen fertilizers, prevent plantings from thickening, and regularly treat them with fungicides.
Video “Solution for getting rid of parasites and diseases on zucchini”
Demonstrative video with instructions for creating a solution that will help avoid the appearance of pests and diseases on zucchini.
