How to treat apple trees against scab in the fall: chemicals, folk remedies, pruning, fertilizing

Apple orchards are often affected by scab. This infection causes serious damage to fruit trees, weakening the plantings and ruining the harvest. Apple trees affected by scab appear unattractive, yields are reduced, and young trees often wither.

Experienced gardeners know that scab must be treated as soon as symptoms are noticed. Proper treatment with chemicals or folk remedies in the fall is effective, resulting in healthy fruit harvests the following season.

Scab: characteristics of the disease

Scab is a disease caused by the fungus Venturia inaequalis, whose spores are ubiquitous. They are found in foliage near trees, in bark crevices, and in the soil. Favorable conditions for its occurrence include:

• rainy weather;
• fogs;
• dense planting of fruit trees on the site.

With a strong apple tree's immunity, the disease causes localized problems and has virtually no impact on yield. However, under favorable conditions, scab develops rapidly, affecting leaves, bark, branches, and fruit. Young apple trees and older trees with weakened immune systems are the most vulnerable.

Numerous gray-yellow spots appear on the foliage, rapidly increasing in size. The leaves then dry up and fall from the branches, affecting the tree's nutrition and fruit set. Spots also appear on the ovaries, and then on the apples, which then harden and crack. Almost the entire surface of the apples darkens, the fruit stunts, wrinkles, and tastes bitter. Apples infected with the fungus are smaller in size and, although not toxic, are unattractive.

This harmful fungus is dangerous to all apple tree varieties, but some are more resistant to the disease. Gardeners in all regions are combating scab by implementing mandatory preventative measures and striving to detect the infection in its early stages.

Why carry out treatment in autumn?

The easiest time to spot apple scab on a tree is during the apple ripening period. The fruits are small, with black spots, and fall off. Autumn is the best time to treat apple trees for the fungus. This is when the harvest has been collected and the leaves begin to fall. Effective treat apple trees in autumn against scab with special preparations so that by spring the plantings will recover from the infection and be healthy.

Treatment of apple scab

Disease prevention is easier, so when planting apple trees, follow a few simple rules. These will help protect your garden not only from scab but also from other insidious diseases of pome fruit.

1. It's important to choose the right location for your orchard, taking into account the specific apple tree varieties and the spacing between seedlings. For tall varieties, leave at least 6 meters between holes, while for shorter varieties, leave 1.5-2 meters.
2. Adapted varieties that are resistant to infections are selected.
3. They take recommendations on agricultural practices seriously: they treat the garden for pests and diseases, feed the trees, and remove leaves and debris.
4. Use chemicals and folk remedies, taking into account recommendations and adhering to instructions. Only then will the garden be protected from pests and infections, and will a bountiful harvest be achieved by autumn.

Chemicals

Having noticed apple scab on a tree, methods for combating the disease in the fall and the new season are determined. Chemical treatments are a priority. The reasons are simple: these products effectively suppress the growth of microorganisms, preventing their reproduction and the spread of infection. Treatments vary in toxicity, but in all cases, trees are treated only after harvest.

General rules:

• spray apple trees after the leaves fall;
• the air temperature should not be lower than +5ºC… +6ºC;
• A dry, windless day is chosen for processing;
• Spray the branches, trunk, young shoots, and also the soil around the trees.

Work in special clothing, following the instructions

Use of fungicides

In garden plots, it is advisable to use products classified as toxicity classes 3 and 4. Their advantages:

• efficiency;
• low danger to humans and animals;
• lacks the ability to accumulate in fruits.

The garden is treated several times per season, using products with different active ingredients. This prevents the fungus from becoming accustomed to specific elements, resulting in better results.

Preparations:

• Horus (for prevention and treatment of scab);
• Strobi (dilute 2 ml of the product in a bucket of water);
• Nitrafen;
• Abiga-Peak (the powder is diluted in water, 50 grams per bucket); in case of severe infection, a double autumn treatment is permitted;
• Rayok is a fast-acting fungicide; apple trees are treated twice in the fall;

Fungicides are recommended to be alternated with biological products. Formulations containing strains of Bacillus subtilis are effective against scab. This subspecies of soil bacteria neutralizes and suppresses the scab pathogen. The following products have proven effective:

• Gamair (available in tablets);
• Fitolavin (release form – ampoules);
• Fitop-Flora-S.

The instructions indicate the application rate, as well as the permitted timing and frequency of spraying.

Use of ferrous sulfate

Gardeners in various regions use ferrous sulfate to combat scab. Apple orchards are typically treated with this product in the spring to improve fruit production. In the fall, treatments help eliminate dangerous fungi. In addition to scab, ferrous sulfate is effective against black canker and septoria leaf spot.

The working solution is prepared immediately before use and applied to apple trees only after the leaves have fallen. Spraying directly onto the leaves causes burns.

Preparation of solution:

• 450 grams of powder are diluted in a bucket of water;
• mix thoroughly;
• Spray the garden at a rate of 15 liters of working solution per 100 square meters.

The shelf life is two weeks. The powder is hygroscopic, so it should be stored only in an airtight container.

Treatment with copper sulfate

Copper sulfate is also used for treatment in the fall. This product is highly acidic, so working solutions with other elements added to the base are prepared for tree spraying.

Solutions containing this element rid the apple orchard of a number of diseases:

• scab;
• curliness;
• phyllostictosis.

Recipes for working solutions:

1. 150 grams of lime and 100 grams of the product are diluted in a bucket of water.
2. Mix equal parts of soda ash and copper sulfateDissolve 100 grams of the mixture in a bucket of water. This mixture, called Burgundy mixture, is less effective than Bordeaux mixture, but it doesn't leave a film on tree leaves.
3. 150 grams of shavings of laundry soap, 20 grams of copper sulfate are diluted in a bucket of water.

Treating apple trees with urea against scab

When treating apple trees with this product, you don't need to wait until the leaves have completely fallen. Urea effectively combats fungus, simultaneously killing pests and saturating the apple tree with nitrogen.

Working solution:

• 100 grams of urea are carefully dissolved in a bucket of water;
• Mix the composition thoroughly.

Apple tree plantings are sprayed twice in the fall, with an interval of 10-12 days.

Fighting scab with folk remedies

Various folk remedies are used to combat Venturia inaequalis fungus. The advantage of these methods is their safety for the environment and humans. However, effective treatments and measures are only effective in the early stages of the disease, and only with regular use.

Means and methods of preparation

Mulching

Also, in the fall, mulch the soil around the apple trees by applying Baikal-EM-1 to the mulch and soil. The microorganisms contained in the fertilizer promote rapid decomposition of the mulch, foliage affected by fungus, and improve the soil.

It is recommended to carefully remove any loose bark, moss, and lichen that appears on the trunk. In the fall, apply a special garden paint to the tree's bark, skeletal branches, and ramifications.

Treating apple trees against scab with soda varnish

Garden pitch is used to seal cracks in the bark. This product is available in specialty stores, but it's also easy to make yourself:

• melt 100 grams of rosin;
• melt 100 grams of beeswax;
• carefully mix the straightened mixtures;
• add the same amount of any animal fat (unsalted);
• mix;
• The bark of apple trees is coated with slightly warmed pitch.

Garden pitch improves the condition of the bark and prevents the spread of fungus along the tree trunk.

Pruning and fertilizing a tree

Scab control isn't limited to just treating your garden with pesticides. A comprehensive approach is needed, including the following measures:

• pruning of fruit crops;
• top dressing with special compounds.

In this case, the age of the apple trees, varieties, soil characteristics, and local climatic conditions are taken into account.

Trimming

First, after the leaves have fallen, inspect the apple tree. Note the areas most severely damaged by the fungus, the foci of the disease, and the shoots that can be revived. Next:

• cut out diseased and weakened branches;
• remove the infected bark from the trunk;
• water the soil around the apple trees with a pink solution of potassium permanganate;
• The trunks and skeletal branches are whitewashed.

After each pruning operation, the tools are disinfected in a solution of potassium permanganate.

Top dressing

The main nutrients for pome fruits in the fall are phosphorus and potassium. Nitrogen supplements are avoided, as they stimulate rapid shoot growth. This is not allowed in the winter, otherwise the apple trees will freeze and die.

Foliar feeding is recommended as it is more effective in combating scab. Ingredients:

• potassium nitrate (5% solution);
• potassium sulfate (10% solution);
• potassium salt (15% solution);
• potassium sulfate (5% solution).

Solutions with mineral fertilizers not only nourish trees, but also have a detrimental effect on pathogens.

Preventive autumn treatment of apple trees against scab

Every gardener knows that it's much easier to prevent an infection than to treat it later. Scab is no exception, and with proper prevention, you can protect your garden from this scourge.

The best time to treat apple trees is in the fall, after the apples have been picked. Spraying during leaf fall and after the leaves have completely fallen is effective. Prune away diseased and dead branches, lightly scrape the bark, and seal the affected areas with garden pitch or a lime-clay solution.

For treatments, combined solutions are used:

• Gamair and Fitosporin-M (diluted in water according to the instructions);
• Gribofit and Immunozot.

These products will prevent scab fungi from developing and spreading throughout the garden. Combining different products in tank mixes allows you to reduce the total number of treatments while still achieving good results.

Boron fertilization

Using boron in small doses doesn't increase fruit set. However, in our case, the preparations are used as a preventative measure against scab.

The following are used for processing:

• boric acid;
• Borogum-M preparation (organomineral additive, diluted in water, used for spraying);
• boron magnesium.

Boric acid is diluted in hot water (0.1 grams of the product is taken per liter of water), and boron magnesium is diluted in the same proportion.

Traditional treatment with copper-containing solutions and approved chemicals

Spraying apple orchards with traditional Bordeaux mixture, as well as copper-containing compounds, produces good results. Gardeners typically use these compounds on apple trees in the spring, but they are also suitable for fall treatment. The traditional working solution is 5%.

Autumn application is only recommended if similar treatments were performed in the spring and summer. Kuprozan and Zinneb are also effective. After leaf fall, apple trees should also be treated with the immunostimulant Zircon.

Peculiarities of scab control

Unfortunately, for many gardeners, the fight against apple scab doesn't stop in the fall. They wage a real war against the infection throughout the season. Apple trees are treated in the spring before the appearance of young leaves, in summer - immediately after flowering and only with safe preparations.

Typically, the scab pathogen ceases its activity during hot weather, and the disease subsides. However, prolonged rains can cause the infection to flare up again, and it's important not to miss this opportunity. It's recommended to monitor weather reports and stay alert.

In August, treating plantings is permitted only in the evening or early morning. In hot weather, any treatments can cause leaf and bark burns. Chemical treatments are not used in the summer, as the chemicals take a long time to break down, up to a month, and the fruit from such trees is unfit for human consumption.

In the fall, when apples are ripening, only folk remedies are used. If scab infestations are severe, the infection is difficult to treat, and nothing can be done. They wait until the harvest and only then carry out all necessary treatments.

Depending on the apple tree variety

Almost all varieties are susceptible to scab, but some are less resistant. If you grow Golden Chinese or Melba in your garden, the risk of infection increases.

Recommended for the following varieties:

• highlight well-lit areas in the garden;
• Treat with anti-scab preparations several times per season, always alternating the formulations;
• Treat apple trees with special immunostimulants that increase the tree's resistance to the effects of harmful spores.

Breeders have developed many varieties with disease resistance. It's advisable to select the most suitable apple trees for your garden, adapted to your region.

By region

The timing of autumn treatments varies by region. Apple trees are susceptible to scab in the south, central Russia, Siberia, and the Urals. Therefore, when spraying, weather conditions must be taken into account, as many products lose their effectiveness when temperatures drop.

In the central zone, gardens are cultivated in October, in the Urals – in September, in the south – October and November.

Apple tree varieties resistant to the disease

When selecting apple tree varieties for orchards, scab resistance is a key factor. More than 120 varieties have been bred to be less susceptible to this insidious infection. A special gene, Vf, was used in the breeding process, increasing the trees' resistance to the fungus Venturia inaequalis. Many of these new varieties do not require the use of fungicides against scab.

For southern regions, the following apple trees are recommended:

• Fontanelle;
• Fairy (fruits are used in dietary and baby food);
• Red amber;
• Juno;
• Lyubava;
• Orpheus.

In the middle zone, gardeners note the following scab-resistant varieties:

• Ranetka (performs well in harsh conditions);
• Geneva (fruits are not suitable for long-term storage);
• Venyaminovskoe.

Of the early, scab-resistant varieties for the Moscow region, we recommend:

• Arkadik;
• Apple Savior;
• Elena;
• Folk.

Among the early autumn apple trees, the leaders are Uslada and Sergiana, and of the late ones, the most frequently planted are Legenda, Imant, and Chashnikovskoye.

The category of varieties highly resistant to scab includes:

• Orlovim;
• Imrus;
• Slav;
• Celandine;
• First time.

When planting orchards, it's important to remember that during periods of epiphytotics, even apple trees with high field resistance can be affected by the pathogen. Therefore, preventative measures are carried out in all situations.

Reviews

Irina, Moscow region

Scab appears on different varieties in different years. It seems there's no particular humidity, but the fungus has appeared on apple trees listed as susceptible. I've noticed that resistant varieties can also be susceptible, while non-resistant ones perform well. I haven't had any problems with Imant and Topaz.

Oleg, Bryansk region

Every season, I treat the trees with various fungicides. I alternate them with pest control products, and I also use various folk remedies. In the fall, I collect and burn the leaves (I don't compost even healthy leaves), and I treat the apple trees with urea. I always water the soil under the trees. Even in rainy summers, any scab that appeared was only in small amounts.

Conclusion

Scab is a dangerous infection, which, without care and prevention, quickly affects fruit crops in the garden. Treating apple trees for scab in the fall and practicing proper agricultural practices will help eliminate the fungus, prevent the spread of the disease, and ensure a harvest of healthy, delicious apples next season.