Powdery mildew (leucorrhoea). Signs of illness.
The first sign of powdery mildew affecting your favorite houseplant is white bloom on the leaves. The stems are gradually affected, and as a result, the whole plant is completely: the leaves wither, darken, dry out and fall off. And this is already a sure sign of the death of the whole flower.
All is not lost and the plant can be saved if you realize in time that it is affected by a disease. Carefully examine the flower and if you find a white bloom on the surface of the leaves, immediately pick them off and treat the whole plant with a soda solution: pour water into a liter jar and add 3 grams. soda, stir and spray the whole flower.
Another treatment option is soapy: 20 grams of green soap and 2 grams of copper sulfate are dissolved in a liter of water. Sometimes they use a combination of the first and second options: mix soda with soap (for a liter of water, 4 grams of soda plus 3 grams of soap). There are methods of treatment with the use of chemicals, for example, ground sulfur - in the form of crushed powder. Usually, a diseased plant is pollinated on a warm early morning, in dry weather, when there is no wind. Frequency - every week.
Traditional methods of treatment
For a long time, at first, plants of the garden-garden type were treated, and then, when they realized the effectiveness, they began to use them on indoor plants. This method is based on cow dung. Take cow dung (1 part), dilute in water (3 parts) and leave for 3 days. To treat a plant that is affected by a disease, it must be diluted with infusion with water in a ratio of 1: 3. Well, if you live in a city, how can you replace manure? Rotted hay or leaves, caked dust will do.
In the apartment, you can use garlic (25 grams), which is crushed and defended in 1 liter of water for a whole day. From their own experience, many experts advise treating flowers for diseases and lesions in the evening, and preferably on the street or on an open balcony, especially if these are methods using garlic or cow dung. The frequency of treatment and treatment is a week.
One of the most dangerous diseases. The causative agents of the disease are two types of fungi, similar in morphology and biology, but strictly “belonging” to their host plant. The causative agent of the scab develops only on the pear, and the causative agent of the apple scab - only on the apple tree.
Mushrooms infect leaves, fruits, less often shoots. Vague oily spots form on the leaves. Later they acquire a gray color and are covered with a greenish-brown velvety bloom of sporulation. Severely damaged leaves dry up and fall off. The same spots appear on the fruits, but sharply limited, often with cracks. With early lesions, the fruits become one-sided. On the shoots, especially pears, spots form, on which the diseased bark then swells, cracks and flakes.
Scab pathogens overwinter in fallen leaves, and on a pear - and on young damaged shoots. In spring, the mushroom forms black spherical fruiting bodies, in which the ascospores ripen. After rain, abundant dew or fog, ascospores are thrown out of the fruit bodies and carried by the air current. Throwing out of ascospores occurs repeatedly and coincides with the period from the separation of the buds to the end of flowering. Getting on young leaves (or pear shoots), the spores germinate, forming a mycelium, which penetrates into the tissue of the leaves (or pear shoots). These are primary infections. A prerequisite for the germination of ascospores and their infection of plants is the presence of droplet-liquid moisture, therefore the disease develops more intensively in years when rain, dew or fog often fall in the spring. Young growing trees are most susceptible to scab. The first signs of scab appear before or shortly after flowering.
On the affected green leaves, the fungus forms conidiophores, invisible to the eye, with conidiospores on them. Conidiospores are carried by the wind and infect healthy leaves and fruits (secondary infections). During the summer, the fungus develops in several generations.
The following apple varieties are strongly affected by scab: Simirenko, Delicious, Starkrimson, Korey, Melba, Borovinka, Mikentosh. Average affected varieties: Jonathan, Idared, Pepin Lithuanian, Superprekos, Red Delicious. The varieties are weakly affected: Parmen winter gold, Calvil snow, Spartak, Janared, anise Kubansky, Welsey, Wagner. Of the pear varieties, winter Michurina is resistant to scab, Forest beauty, Tonkovotka are strongly affected.
Control measures. Collecting and burning, composting, or burying leaves in the fall after leaf fall. Spores are not formed in the leaves covered with earth. It is recommended to dig up the soil in the fall with a careful incorporation of fallen leaves.
Thinning of the thickened crown of trees. Good crown ventilation is unfavorable for scab development.
Effectively spraying apple and pear at the beginning of bud opening (along the "green cone") 3-4% Bordeaux liquid or in the phase of bud separation with 1% Bordeaux liquid. After flowering, the trees are sprayed with 1% Bordeaux liquid or its substitutes (copper oxychloride, polychoma). 18-20 days after flowering, the apple tree is again sprayed with copper oxychloride, polychoma, Vectra or speed preparations.
Any of those flower growers who are engaged in the cultivation of indoor roses knows that the two main main troubles of this flower are - powdery mildew and spider mites... And with that and with the other trouble, I also know firsthand.
I first encountered powdery mildew on roses in the spring, immediately after the central heating was turned off. The temperature in the apartment at that time was not very high, plus everything was aggravated by the high humidity in the room with a large aquarium. I noticed powdery mildew not immediately, but only when half of the flower was already covered with a white bloom.
The first remedy in the struggle was folk soap and soda diluted in water. It didn't help me a bit, so I went to a flower shop and they recommended a blue powder. Unfortunately, I don't remember the name. As a result of manipulating this powder, the leaves of the poor flower were covered with a bluish bloom, it began to look terrible, and the powdery mildew never thought to go anywhere.
On the Internet, in various forums, it was advised to purchase Topaz... And it was for this remedy that I went the next time.
The product is a fungicide and is intended to combat powdery mildew.
The product is sold in the form vials and glass ampoules... I chose a bottle, despite the fact that it costs much more than an ampoule, but it can be diluted several times.
I dilute the product in a bottle with a sprinkler, from which I actually spray it later. Spraying is done by putting the flower in the bathtub in the bathroom, since it is easier to clean it later than a closed balcony.
The smell of the product is very similar to the smell of hydrocyanic acid, it is well felt during spraying.
After spraying, I leave the flower in the bathroom for a while.
With the correct dosage of the drug, it does not affect the flower itself in any way. The leaves remain the same green without any bloom. If the dosage is incorrect, it can cause leaf burns. But I had it only once, apparently I went too far with the remedy.
Powdery mildew disappears immediately after the first spraying, and the flower pleases me with its beauty.
A single spring spraying is enough for me before the cold snaps begin in the fall, when dew may reappear.
Where does powdery mildew come from?
The pathogens of the spheroteca reproduce both sexually and asexually.
- Asexual reproduction occurs with the help of conidia - these are immobile spores, so named from the Greek konia - dust and eidos - a species. It is the chains of conidia that we see on the leaves of infected plants in the form of a white bloom, they easily break away from each other and are carried by the wind over a decent distance. So during the entire summer season, new shoots and plants are regularly re-infested.
- Sexual reproduction is carried out through spore-bearing structures - cleistothecia. This fruiting body of the fungus is composed of very tightly intertwined hyphae and can contain millions of spore sacs, each of which usually contains four to eight ascospores. Cleistothecia hibernate on fallen leaves, and in spring the ascospores ripen, are released and give rise to a new focus of infection.
At the time when cleistothecia are formed, the plaque on the leaves turns from white to gray, then brown - the fruit bodies themselves (clestothecia) are brown or black in color, and the size does not exceed 0.2 mm.
Prevention of powdery mildew
In order not to bring the plants to damage by powdery mildew, it is recommended to take preventive measures.
Simple tips will minimize the risk of this fungus appearing in the garden:
- Compulsory burning of all damaged shoots and leaves.
- Regular harvesting of weeds that can cause powdery mildew.
- With the correct organization of crop rotation, it is possible to minimize fungal infection of other crops.
- Planting seedlings that are genetically protected from this pathogen.
- Plant the bushes at a sufficient distance from each other so that full air circulation occurs.
- Disinfection of tools for gardening.
- Morning watering of bushes. Thus, in the daytime the earth will be dry, which will prevent the development of the disease.
- Do not use large quantities of nitrogen-containing fertilizers.
In appearance, it resembles a thin white cobweb formed on the vegetative organs of the currant. Mostly red currants are affected.
A white powdery coating resembling felt is formed on the leaf blade.
Affected berries and leaves crumble, and the shoots stop growing and bend.
To grow healthy and strong red currant bushes, preventive measures, as well as competent care, cannot be neglected..
All diseased branches are cut and burned.
Before bud break, the shrubs are treated with a 3% solution of ferrous sulfate.
In the spring, during the growing season and flowering, humus and mineral fertilizers should be applied. In autumn, feed with organic matter.
Water intensively during fruiting and flowering.
Mulching the trunk circle can protect the plant from the harmful effects of frost and snow, make it from straw or peat.
Timely weeding and loosening of the soil.
Avoid the accumulation of pests on the shrub. Treat currants with drugs against infections or insects.
In October, arrange sanitary pruning of the bush.
The main measures for the destruction of powdery mildew mycelium is spraying currant bushes with various preparations. Currants are sprayed with Fitosporin, Fitodoctor, Horus, Paracelsus. You can use folk remedies: garlic water, solutions of dry mustard and mullein, as well as iodine, dissolve one bottle in 10 liters of water and process shrubs with an interval of 3-4 days.
(The material was prepared by specialists of the Rosselkhoznadzor Administration for the Republic of Mordovia and the Penza Region).
What to do for prevention
Observing the rules of agricultural technology for growing cucumbers, you can protect them from infection with powdery mildew. So, you need to make sure that there are no plants within a radius of 20 m that are sick with this fungus.
Basic rules for the prevention of powdery mildew on cucumbers:
- Cucumbers can be planted in the old place only after 3 years. Do not choose places for beds in lowlands and in the shade. The soil in the area where the cucumbers are planted is periodically loosened. After harvesting, you need to completely clear the planting site of plant debris and weeds, and water the ground with a solution of potassium permanganate.
- Seeds are pre-treated with hot water (+ 55 ° C) or special means: "Trichodermin", "Grandsil". Seeds or seedlings are placed in soil warmed up to +12 ° C.
- The temperature in the greenhouse must be monitored. During the day it should be about + 20 ° C, but not higher than + 30 ° C, at night - + 17 ° C.
- When watering, the drops should not fall on the leaves and stems. Sprinkle with water no colder than + 20 ° C.
- In order for cucumbers to grow strong and can withstand powdery mildew pathogens, they need to be fertilized. A bucket of liquid requires 6 g of ammonium nitrate, 10 g of urea, 8 g of potassium chloride, 10 g of superphosphate.
To prevent infection with powdery mildew, planting cucumbers is treated with the following compounds:
- Copper sulfate - 5 g, soap - 50 g, water - 5 liters. Cucumbers are sprayed 2 times, taking a break of 7 days.
- Mustard powder - 2 tbsp. l., warm water - a bucket. It is used for watering.
Ready-made preparations "Topaz", "Quadris", "Planriz" and "Strobi" can be used to treat powdery mildew on cucumbers, but they are more effective in preventing the disease. They can be used to spray seedlings that have 5 leaves each. Before flowering, processing is carried out every 2 weeks.