Peppers of any variety are demanding in terms of growing conditions and are often susceptible to disease, especially in regions with cold climates, low light, and short summers. A pale bush, wilted leaves, and numerous light spots on the green parts can be signs of a serious disease that will threaten the entire planting, not just a single plant. Even in a heated greenhouse, young pepper seedlings or adult plants can die if the cause is not identified in time and measures are not taken.
Common causes
Plant leaves turn white when infected by bacteria, fungi, mold, pests, or parasites, or due to improper growing conditions. A thorough inspection of the plant can help identify the specific cause. It's not necessary to destroy it, and it's not always necessary to isolate it. However, if the leaves of your pepper seedlings have already turned white, it's important to determine the type of infection before moving them from the boxes to the ground or greenhouse.
You may be interested in:Whitening of pepper leaves is most often caused by a deficiency of certain nutrients. The plant itself responds poorly to fertilizer during the growing season, actively drawing nutrients from the soil. Green parts must be pruned at least 14 hours a day, which is virtually impossible in most regions. Consequently, the plants may lack the essential elements needed for growth and development, leading to degenerative processes. Diseases that fall into this category include:
- Fusarium wilt;
- late blight;
- chlorosis;
- Verticillium wilt.
The most dangerous of these types of wilting is the one listed above. It is virtually untreatable and appears after flowering. Fusarium wilt becomes evident after the fruit growth phase, while verticillium wilt manifests itself during the active fruit set phase, immediately after flowering. Peppers begin to develop lower leaves that turn white. Gradually, the tips begin to lighten. Bushes slow in growth, new foliage fails to appear, and flowers begin to fall off. Even under favorable weather conditions, ripening or fruit set does not occur, flowers gradually fall off, and existing peppers change their structure and disappear right on the plant. Specific symptoms include leaf curling, which can begin after planting outdoors. Wilting is incurable and ultimately results in the death of the plant, which must be disposed of away from the main plantings.
Chlorosis and late blight are diseases associated with metabolic dysfunction in plant tissues. Leaves gradually become covered with small specks, and their tips dry out. The light, dull shoots gradually thin out, and the lower leaves begin to turn completely white, followed by the upper ones. This pepper can also infect other vegetable crops.
Pepper leaves and stems are also vulnerable to fungal diseases. They may not turn white immediately; you may first notice individual small spots. If the disease is not identified promptly, the entire planting will be at risk. Causes of whitening stems may include:
- blackleg;
- white rot;
- gray mold;
- marsupial fungus;
- powdery mildew.
The last type of damage is the safest for the plant. Powdery mildew often attacks the leaves of young bell pepper seedlings kept in greenhouses. Here, high humidity and stable temperatures promote the growth of colonies of pathogenic microorganisms. The leaves then lighten unevenly and randomly, becoming covered with large, irregular spots. Powdery mildew is easily cured even in greenhouses, and with timely treatment, it does not affect the harvest.
The marsupial fungus spreads from the stem near the roots to the lower leaves and beyond. You may notice that the green parts not only become lighter in color but also covered with small black spots. Unlike this disease, gray mold affects the entire bush, including already formed fruits. The affected areas grow rapidly, eventually leading to the death of the plant. A light-colored coating is also characteristic of white mold, which develops over a long period and does not disappear even after planting outdoors. This disease has no obvious symptoms, but you may notice slow growth of greenery and fruits. In this case, the pepper dies gradually.
A dangerous fungal infection can also lead to cladosporiosis, septoria, and alternaria. These diseases are mycotic in nature, making them highly contagious. Fungi can live in soil, on containers, and even on garden tools. Poor watering practices and high temperatures with sufficient humidity only encourage their spread. These diseases manifest themselves in almost the same way: large, grayish spots begin to spread from the root zone and quickly spread to the leaves. The leaves wilt and then fall off. A white coating begins to cover the inner surface of the leaf, while lighter spots are randomly distributed, gradually coalescing.
Treatment methods
If the leaves have already changed color, simply fertilizing the plants won't be enough. It's important to determine precisely what element is lacking in the soil and what fungus is causing the disease. Since the symptoms of these diseases are similar, making a "diagnosis" by eye is virtually impossible. However, this is often unnecessary; identifying the disease group is sufficient to select the appropriate treatment.
Bordeaux mixture is effective in the early stages of infestation. It is also a good preventative measure before planting. If a ready-made solution is not available, one can be made from copper sulfate, quicklime, and room-temperature water in quantities of 100 grams, 240 grams, and 10 liters, respectively. If the infestation is severe and treatment has not been completed in time, the amount of solution can be reduced to 7 liters.
Before planting, the area should be treated, fertilized, and supplemented with the necessary biologically active ingredients, such as "Alirin-B." Dissolve one tablet in 5 liters of clean water. Spray the soil a few days before planting; the specified amount is sufficient for a 5-meter square. If the area was already affected by a fungal disease last season, pour a small amount of the solution into the hole immediately before planting the seedlings. This is effective against septoria and similar diseases.
You may be interested in:Already grown bushes are sprayed with biologically active products such as Quadris or Trichodermin. The solution is applied to plants, including those with flowers and fruits. The substances penetrate the tissue structure and strengthen it, stimulate photosynthesis and other metabolic processes, and literally boost the pepper's immunity. This measure is especially effective against powdery mildew.
Care and prevention
When treating any disease, it's important to eliminate any negative effects on the plant. This includes carefully fertilizing the bushes, ensuring timely watering, providing protection from cold air and drafts, and eliminating shade and insufficient light. These same measures are the best preventative measures against all of the above-mentioned diseases. Leaves often turn white, dry out, and fall off simply because of improper care of the pepper.
The first step in proper care should be soil preparation. This should be done according to the soil type and its acidity. The vegetable dislikes high acidity, so it's best to add compost or manure as fertilizer, and use sawdust and sand for mulch. Ash can also be used to disinfect the soil, which will also shift the balance toward alkalinity.
If leaves begin to lighten or fade, or lose their elasticity, you should fertilize your plants with mineral fertilizers. These will help enhance photosynthesis. During inflorescence formation, it's best to use nitrogen-containing compounds; during active ovary formation, add boron and its compounds; calcium is beneficial when the first ovaries appear; and potassium during pod growth. It's best to use minimal concentrations, as the plant is sensitive to overdoses. Repeat this procedure every 2-3 weeks. The following nitrogen-containing fertilizers, at recommended concentrations, are most effective for peppers:
- saltpeter 30g per bucket of water;
- mullein infusion in water in a ratio of 1:20;
- urea 20g per 1 bucket.
It's important to regularly water the peppers during treatment. Peppers prefer moist soil but are vulnerable to fungal infections. Therefore, it's best to water them daily, but with small amounts of warm water. If the soil hasn't dried out yet, you can shift the watering time or skip a day. To prevent the spread of disease, increase the distance between plants and avoid dense plantings near the bed, as this will interfere with natural air circulation.
Greenhouse or soil
Growing peppers in a greenhouse and in the open ground has its own unique challenges. If you don't take proper care of the plants, the risk of disease increases. If you plant peppers outdoors, it's important to adhere to the hardening-off and transplanting schedules. This should be based on the climate and the variety's characteristics. Insufficient heat and light will harm the plants. It's best to find a location protected from drafts right away. It's also important to consider crop rotation practices. These plants require slightly more frequent watering, and the soil should be loosened accordingly to ensure adequate oxygen supply to the roots.
In a greenhouse, high humidity can be the main problem. It's important to control this by providing regular ventilation. Since it's difficult to rotate crops, special attention should be paid to fertilizing in the fall after tilling and in the spring before planting. If pepper leaves are turning white, they may not be getting enough light in the shelter. In this case, replacing the cover or installing opening doors will help. It's also important to remember that fungal diseases spread much more quickly in a greenhouse, so it's important to inspect the plants daily to monitor their condition.
If your pepper plant's leaves have turned white, it indicates significant care deficiencies that have already led or could lead to infection with dangerous diseases. Discoloration is one of the first symptoms of white rot, powdery mildew, cladospirosis, and various types of wilt. In some cases, prompt treatment can save even an affected plant and produce a full harvest. However, it's important to promptly identify terminally diseased plants, which can ruin the entire planting.
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