Powdery mildew on vegetables - methods of prevention and treatment
Powdery mildew is a fungal disease that occurs on any plants and is especially violent when there is an abundance of heat and moisture. Our grandfathers and grandmothers, when they came to the garden and saw an ashen coating on the leaves, sadly noticed that an ashtray or linen had come, as it was called even earlier. The fact is that this very linen, outwardly from a harmless cannon, can turn into a monster, capable of destroying most of the crop or even the whole, if you do not fight it. We will tell you about what powdery mildew is on vegetable crops, what harm it can cause to tomatoes, cucumbers and other vegetables, and how to defeat it, in the article.
- Powdery mildew - fungal infection
- Symptoms and consequences of powdery mildew
- When is powdery mildew most active?
- Powdery Mildew Prevention
- Common Powder Mildew Treatments
- Powdery Mildew Treatment for Vegetables
- Powdery Mildew Drug List
- Folk methods of controlling powdery mildew
Powdery mildew - fungal infection
In fact, powdery mildew is a fungal infection that spreads (and then actively develops) not only in the wind or insects, but also in microscopic fungi located right under your feet in the soil. They belong to a complex in name, but, in fact, the simplest order of powdery mildew, or erisif.
As we already mentioned, powdery mildew is “omnivorous”, it can eat your favorite vineyard, beautiful roses, gooseberries (because of it its area is significantly reduced), almost any crops, peaches, as well as cucumbers, squash and pumpkin, sugar beets and other vegetable plants.
Symptoms and consequences of powdery mildew
The very first symptom that you should pay close attention to is, of course, powdery coating, and sometimes it happens from the bottom of the leaf (this is downy mildew) and from above (real). And if the children didn’t run around the site, scattering something mealy on the plants, and besides, the plantings were thickened, the soil was not the first freshness, and it rains more often than we would like, then there is only one verdict - this misfortune, unfortunately, did not escape . Sometimes on a whitish plaque clearly visible droplets of moisture can appear, but plaque may well be without them.
Usually in vegetable crops, powdery mildew shows itself not only on leaf blades, it can also be on petioles, and on young shoots, as well as on fruits and stalks. The very first infection penetrates precisely through the leaf blades, and the closer the leaf is pressed closer to the ground, the more likely it will become infected. The same applies to the shoot of a vegetable plant - it is pressed to the ground, which means that the probability that it will become infected will be maximum. And then everything is simple - the disease captures the entire vegetable plant as a whole.
If you are a nerd by nature, then you can, armed with a magnifying glass, take a closer look at the places where the mycelium joins the leaf and the ulcers formed in this place. It is clear that the plant will begin to wither away, because the fungus will pull on most of the nutrition and moisture, and the leaves under the layer of the fungus will not be able to carry out normal photosynthesis processes.
Perennial vegetable crops have reduced ability to winter hardiness and resistance to negative environmental factors. At the same time, quite large cracks are formed on the affected fruits of vegetable crops, into which the infection penetrates, rot develops actively, and the product simply becomes unusable.
When is powdery mildew most active?
Powdery mildew is most active on vegetable crops in excessively wet years (65-75%), accompanied by temperature fluctuations from +14 to + 26 ° С. Powdery mildew of vegetable crops is activated with frequent fluctuations in day and night temperatures, as well as due to inept actions associated, for example, with incorrect pinching of tomatoes, when hemp (parts of the stepson) or leaves located at the very bottom of the plants are left.
In addition, powdery mildew often attacks vegetables, if the gardener makes too large doses of nitrogen fertilizers, this reduces the immunity of plants, and powdery mildew is right there. Naturally, you should not save space and plant a lot of plants on the same area, trying to grow a grandiose crop, the planting scheme must be strictly observed, otherwise the moisture will not normally evaporate from the soil surface, creating favorable conditions for the development of powdery mildew on vegetable crops.
Usually, the density of planting also determines the watering regime - the gardener thinks that since he planted the garden so tightly that there is no free space, then the plants experience just the wildest deficit of moisture and they urgently need help. He takes a hose and turns everything into a swamp, thereby creating the prerequisites for the appearance of powdery mildew.
Violation of the irrigation regime is another reason for the appearance of powdery mildew in the garden. Often at the dacha, appearing once a weekend, we too generously water our vegetable crops, and then forget about them, literally opening the gates and letting powdery mildew into our area ourselves.
Powdery Mildew Prevention
Naturally, powdery mildew can be fought, but prevention is very important, and you should not immediately use chemistry at the first signs of the disease in vegetable crops.
Preventive measures are needed and effective. For example, you need to water the plants only after the top layer of the soil has completely dried, and if it rained and the soil is moist, then you should not moisten it again, because these are not tree crops, and their roots are not so far from the soil surface.
The second measure - it is imperative to observe crop rotation, remove all plant debris from the site immediately after harvesting the entire crop. Another important preventive measure is the cultivation of powdery mildew resistant varieties and hybrids of vegetable crops. And yet - no overfeeding with nitrogen fertilizers, especially during periods of bud formation.
By the way, about fertilizers: warning you against introducing an excess of nitrogen fertilizers, we recall that you need to add potash (8-10 grams per square meter) and phosphorus fertilizers (7-9 grams per square meter) to fully nutrition the plant and increase their immunity.
Soil after harvesting the plant residues still needs to be treated with fungicides, strictly following the instructions on the packaging and only with those drugs that are allowed. One time, by the way, may not be enough to eradicate the disease completely and completely, it is better to carry out three, or even four treatments.
Common Powder Mildew Treatments
So, we realized that powdery mildew is a very unpleasant infection, and even if we took all precautions, it can still appear on vegetable crops and, at best, deprive us of part of the crop (or maybe all). Therefore, let's figure out how you can remove this infection from the site and never let it in again.
If you are not a fan of chemistry and have noticed that leaflets on vegetables have acquired a characteristic powdery coating, then, as carefully as possible, wetting the scissors in alcohol each time and rubbing sections with wood ash, remove all affected leaflets of vegetable crops from the site and burn them outside.
Reduce the amount of irrigation water to a minimum, and better, loosen the soil daily and remove harmful weeds from the site. Everything is simple here: the more you remove the leaves affected by powdery mildew, the more you will reduce the chances of infection of the remaining organs of the plant or neighboring vegetable crops.
After this, it is strongly recommended that you treat the plants with fungicide, so to speak, to consolidate the result. The main thing here is to use an approved, fresh fungicide, strictly following the instructions on the package where, as a rule, the processing time for each culture and dosage are indicated. When treating with a fungicide, try to moisten all the organs of the vegetable plant - its upper and lower parts, so that the fungicide processes everything that is possible, and there are no corners infected with the infection.
Powdery Mildew Treatment for Vegetables
Powdery mildew on cucumbers
It’s unlikely that it will be possible to describe the protection against powdery mildew on all vegetable crops without exception in one article, we need a whole book. Let's talk about the protection against powdery mildew of the main vegetable plants, which, as a rule, are on the site of each.
If powdery mildew is found on the cucumber leaf blades, first of all, stop watering, then remove all diseased leaves, try to thin out the plants. For example, if any of them is very severely affected, then it is best not to treat it, but to banally remove it from the site.
Next, be sure to loosen the soil to enhance the evaporation of excess moisture, and you can begin treatment. It is known that excellent results are obtained by banal dusting of the affected cucumber leaf with sulfur powder. To prepare it, you need to take 28-29 g of sulfur, dissolve in a bucket of water, fill it with a spray bottle and try to process all the affected leaves and the soil beneath them.
A solution of colloidal sulfur also helps, it needs the same amount for the same volume, only if in the first case it is possible to spray 5-7 square meters of diseased plants in this way, then in the second - all ten. Treatments are best done in the evening. Some gardeners respond well to the treatment of affected cucumber plants with 10 times diluted mullein, this amount is enough for 10 square meters of beds.
If you decide to use fungicides, then strictly use the instructions on the package (terms, doses, take everything into account). Find out if a particular drug is allowed. Previously, copper-based preparations like “Oxychoma” helped to cope with powdery mildew, now they write that there is little sense from them, you can use the fungicide “Topaz”.
Powdery mildew on tomatoes
It is interesting that powdery mildew on tomatoes can occur in two forms, or rather affect plants with two types of fungus. The first species is Oidiopsiserysiphoides - mainly in open ground, that is, not in greenhouses and greenhouses. Infection of tomato plants with this type of fungus usually occurs in March. As a rule, already on tomato seedlings, the leaves begin to dry from the edges, and if you tighten it to eliminate this problem, then the seedlings usually die trite.
The second pathogen is the fungus Oidiopsistaurica, its external signs appear as yellow spots that are located on the upper side of the tomato leaves, but the snow-white coating, typical of powdery mildew, first appears just below the leaf.
To minimize the outbreak of these two fungal infections, it is necessary to soak the tomato seeds before sowing for a couple of days in a solution of "Epina" or "Heteroauxin", "Zircon" and similar preparations, which somewhat enhance growth and significantly strengthen the immunity of plants.
But what if the tomato infection has already occurred? The very first way is to treat all tomato plants, both healthy and sick, with sodium humate. This drug contributes to inhibition, up to a complete stop, the growth of conidia - the causative agent of infection, and, therefore, inhibits the development of the infection itself.
Processing must be carried out in accordance with the instructions indicated on the package, use the dose correctly and be guided by the recommended processing time. In addition, at the initial stages of the development of a fungal infection, biological agents can cope with the destruction of powdery mildew, at least the well-known one percent solution of Bactofit, which is used to spray tomato plants three times every week, naturally, as soon as signs of powdery mildew appear .
According to gardeners, a so-called culture fluid called Planriz gives a good effect, but it is effective for the very first signs of the disease, so tomato plants will need to be carefully monitored to identify these very signs.
If the plants are already quite infected, then you need to use approved and available fungicides (again - in strict accordance with the instructions on the package). It can be such drugs as Strobi, Topaz, Quadris, Titovit Jet, Bayleton and even Privent. Gardeners advise, especially in wet years, when powdery mildew is actually rampant, so that the drug stays longer on plants, add laundry soap (usually a half-cup per 10 l of solution) to the solution.
With a slight defeat of tomato plants with powdery mildew, it is quite possible to not use chemistry. Gardeners note that treatment with 10% whey gives a good effect, both for preventive purposes, when it is damp and warm, but powdery mildew has not yet manifested, and for medicinal ones when only a few leaves have been affected, but they are so sorry to pick them off.
The main thing is that after treatment with milk whey it does not rain, otherwise everything will have to be done anew. Some note the effectiveness in the fight against powdery mildew and ash solution, for this, about 100 g of wood ash is poured per liter of water and the infected plants are watered with this volume, spending the solution so that it gets on the infected parts. In this case, you can double the frequency of loosening the soil and halve the watering of the soil.
Powdery mildew on zucchini
Zucchini is another common vegetable crop in our beds, and what a pity, when elegant leaflets are suddenly covered with a white powdery coating. At the first signs of damage, when there are very few affected leaves, they must be carefully cut and burned, and the places of the cuts should be covered with wood ash. If shoots are affected, then you will have to remove them, after which the soil needs to be loosened.
Their folk remedies for the fight against infection can be helped by treatment with a solution of soda ash (10 g per bucket of water) or ten times diluted mullein (at a rate of 50 g per plant). Often the treatment of the affected areas with an ash solution helps, for this you need to take 50 g of ash, dissolve in a liter of water and spray from the spray gun in the evening in calm weather on the affected areas.
Folk remedies do not cope? We will have to use chemistry, again - the approved drugs in strict accordance with the instructions previously helped well: Kefalon, Karboran, and even phosphoric sodium.
As a prophylaxis against powdery mildew, zucchini can be treated a week later after transplanting the seedlings with a drug called “Nitrafen”, and medical preparations should be used after flowering.
Remember, if you use fungicides or use folk remedies to combat powdery mildew, always carry out the treatment in the evening and in dry weather.
Powdery mildew on eggplant
Experienced gardeners argue that it is possible to lime powdery mildew on eggplant in two ways by treating them with a solution of plain soda ash, in exactly the same proportions as we wrote about it in the section about zucchini. Well, those who want a reliable result, let them use fungicides, such as Fundazole. It needs only 10 grams per bucket of water and this norm is enough for ten square meters of land. By the way, eggplant can be processed up to five times during the growing season with foundationol, the main thing is to strictly follow the instructions on the packaging.
Powdery mildew onions
The onion is often struck by the downy powdery growth, it seems to be hiding behind the leaves and it is not always possible to find it. Usually, downy mildew appears on the onion during a period of excess moisture in the soil and in thickened plantings. The first affected leaves need to be pulled out, and then fungicides should be used.
Powdery Mildew Drug List
By the way, since we could not tell about all the vegetable crops that powdery mildew can affect, we will first list fungicides that are effective literally on every vegetable crop (of course, when used in strict accordance with the instructions on the package).
These are “Skor”, “Quadrice”, “Hom”, “Vectra”, “TiovitJet”, “Fundazim”, “Fundazol”, “Vitaros”, “Bayleton”, “Phthalan”, “Tsineb”, “Kuprozan”, “ Topsin-M ”,“ Fitosporin-M ”,“ Previkur ”,“ Switch ”, Bordeaux liquid, vitriol, copper chloroxide, colloidal sulfur and others.
Folk methods of controlling powdery mildew
Against this background, of course, you can’t get around folk remedies for the control of powdery mildew in vegetable crops, let's briefly introduce them.
So, very effective, especially in the initial stages of the development of the disease, is the treatment of the affected areas of vegetable crops with soap-soda solution. To do this, in a bucket of water, preferably rainwater, dilute 45-55 g of soda ash or ordinary baking soda and add 18-20 g of liquid soap or, finely grated, ordinary. Next, you need to shake it all well, bringing to a homogeneous composition and treat the plants twice with an interval of a couple of weeks.
The second option is a whey solution. To do this, about a liter of whey can also be poured into a bucket of rain, that is, soft, water, mix well and this solution can be carried out with up to three treatments in dry weather, taking a break of three days.
Kefir, here you need a liter of well-fermented kefir or yogurt, dilute in a bucket of water and treat the affected plants with the mixture three times with an interval of four days.
A decoction of horsetail is considered more effective, for this you need to chop one hundred grams of horsetail into small pieces and fill with a liter of water, then let it brew for 24 hours under a press, boil for a couple of hours, cool, dilute with water one and a half times and you can carry out up to five treatments of plants with an interval of a week. It is interesting that such an infusion can be safely stored for up to a week without losing its properties.
Mustard solution - you just need a couple of tablespoons diluted in a bucket of water warmed up to room temperature, and this solution can be used to treat infected plants every three days.
Gardeners also speak well of ash solution. To prepare it, you need a kilogram of finely crushed wood ash, dissolved in a bucket of water and well mixed. After this, the solution should be allowed to brew for a week, strain the solution and add a half of a bar of laundry soap to it. Treatment with this composition of diseased vegetable crops can be carried out in a day.
Mullein infusion - it must be diluted ten times with water, and then insisted for three days. After this, the infusion must be carefully drained and filtered to obtain a liquid that can pass through the spray gun. It is important to carry out treatments with this infusion before the plants bloom, and after that you can cultivate the soil by removing all weed residues from it.
Infusion of garlic (burning mixture) - here you need to grind 50 g of cloves, pour a couple of liters of rain water and let it brew for two days. Then you need to strain and process with it only a plot of vegetable plants affected by powdery mildew, without touching healthy ones.
In conclusion - the infusion of onion peels, this is a weak fungicide, and a source of trace elements that strengthens the immunity of vegetable crops. All that is needed is to pour 250 g of onion peel into a bucket of boiling water and let it brew for a couple of days, after this it is necessary to strain the composition and they can be sprayed with plants before and after flowering, as well as cultivating the soil to kill the wintering stage of the pest.
That's all we wanted to tell about powdery mildew in vegetable crops and how to deal with it in all possible ways. And what methods do you use in the fight against powdery mildew? Tell us about it in the comments in the article.