Causes and signs of petunia diseases, how to fight and what to do for treatment
In regions where it gets warm early, petunia seeds are sown directly on the flower bed, but more often flowers are grown from seedlings. Already at this stage of development, a relative of nightshade crops often has diseases, petunia attracts harmful insects. The infection is transmitted with seeds contaminated with fungal spores and bacteria. You can cure the plant if you notice the problem in time.
What diseases is petunia susceptible to?
A herbaceous shrub native to South America, it adores humid and hot weather. When planted in temperate latitudes, the plant becomes susceptible to pathogenic microorganisms that provoke the development of diseases. At the flower, leaves begin to wither, buds fall off.
Blackleg
Seedling stems soften and darken if petunia seeds are planted very densely in high acidity soil. With frequent and abundant watering, pathogenic fungi are activated, and the flower is affected by a black leg. To prevent the onset of disease, thickening should not be allowed. Before sowing the seeds, the soil should be diluted with lime, not overflowing the seedlings, but also make sure that the substrate does not dry out.
Shoots infected with black leg must be removed from the ground, and healthy petunia should be treated with Metaxil, Oxadixil, Mancozeb fungicides.
Gray rot
Strong soil moisture, the introduction of large doses of nitrogen fertilizers, poor lighting contribute to the reproduction of a harmful fungus, which serves as a causative agent of gray rot.
The disease affects the roots, but then:
- Brown spots appear on the stems.
- The leaves are covered with a fluffy bloom.
- The plant dries up.
If signs of rot are detected in time, petunia is sprayed with the preparations "Skor", "Maxim", "Integral". With proper care, the flower is rarely affected by a fungal infection.
Brown spot
When growing seedlings in a greenhouse, where the air humidity is significantly increased, with frequent and abundant irrigation, the water in the soil begins to stagnate. Brown or brown spots form on the leaves of petunia. The disease is fungal in nature; to treat the plant and destroy spores, every 3 days the flower is sprayed with Bordeaux liquid or copper sulfate. Treatment of petunias with ammonia diluted in water helps to eliminate stains.
Powdery mildew
If a decorative flower grows on a flower bed or balcony, when the temperature drops to 18 ° C and rainy weather, the risk of powdery mildew increases. The disease develops with a dense planting, excessive or insufficient irrigation and is accompanied by the appearance of whitish spots that quickly increase and turn into ulcers. Plaque interferes with photosynthesis, and fungal spores travel to other plants. To deal with the spherotek:
- The top layer of the earth where the petunia grows is removed.
- Diseased leaves are torn off, infected shoots are removed.
- Flowers are sprayed with fungicides.
The preparations "Skor", "Fundazol", "Vitaros" effectively fight against powdery mildew. In the early stages of the onset of the disease, you can use folk recipes. Two tablespoons of soda and soap are poured into 5 liters of water. With this composition, petunia is treated 2 times. Flowers are sprayed:
- potassium permanganate;
- infusion of garlic cloves;
- copper sulfate.
Mustard is not tolerated by fungi, 1.5–2 liters of powder are poured into a bucket of water and watered with the roots of the plant, sprayed over the leaves and stems.The treatment of the flower with serum, which must be diluted in a ratio of 1:10 to the liquid, helps to stop the development of the disease.
Petunia is sprayed with a composition that is prepared from a glass of milk, 600 g of water and 10 salt. If you don't know how to deal with the spherotek, you can be left without flowers.
Downy mildew
In warm and damp weather, fungi begin to multiply on petunias, snapdragons, poppies, verbena, which leads to the appearance of peronosporosis. From above, the leaves of the flowers turn yellow, a white bloom forms on the inside. The shoots are covered with cracks, the petals turn black, the plants lose their decorative appearance. The causative agents of downy mildew live for years in the ground and, under favorable conditions, infect both seedlings and flowering plants.
When the leaves are covered with bloom, it is no longer possible to save them, but at the initial stage of the onset of the disease, petunia is sprayed with fungicides "Ridomil Gold", "Fitosporin-M", "Vectra", folk remedies are used. A tablespoon of soda ash and 5 g of soap are mixed with half a bucket of water and the plants are treated every 3 days.
Chlorosis
Petunia grows poorly in depleted soil that lacks minerals. With iron deficiency:
- The flowers are stained.
- Leaves curl.
- Shoots dry up.
Chlorosis causes the roots to die off and the plant withers. To cope with the disease, a flower bed or pot is watered with water, adding half a teaspoon of citric acid and ferrous sulfate to it. The flowers are fed with the Ferovit preparation, the buds are cut off on the affected plants.
Late blight
Petunia planted in a flower bed or in a balcony box reacts negatively to changes in external conditions. With a sharp drop in temperature, prolonged damp weather, flowers are affected by late blight. The disease begins to develop in the lower part of the shoots, then the entire stem rots, and within a few days the petunia dies. It is not possible to save the plant, but the cultivation of soil and containers for flowers with copper sulfate, fungicides "Ridomil", "Profit" helps to prevent the appearance of late blight.
Petunia pests
The succulent leaves of the ornamental plant attract insects. Parasites enter the flowerbed with seedlings, fly from other crops.
Aphid
The microscopic pest attacks various parts of the petunia, covering them with a sticky and sweet coating, which attracts a sooty fungus. The leaves, on which aphids settle, change shape and curl, flowers and buds crumble.
The pest is destroyed by beneficial insects in the form of a lacewing and a ladybug. The smell of tobacco repels the parasite. To deal with aphids completely, the petunia is sprayed with water solutions "Aktara", "Decis", "Confidor".
Whiteflies
The tiny insect lays hundreds of eggs, from which voracious larvae hatch.They drink juice from the leaves, and the plant turns yellow and withers. Not all insecticides cope with the whitefly, the pest dies after three times treatment of petunia with Iskra, Aktara, which are produced on the basis of permethrin.
These products must be used carefully, as they destroy beneficial insects.
Spider mite
Flowering plants suffer from parasites, which pierce the leaves with their proboscis to feast on the juice. The presence of a gluttonous pest is indicated by the appearance of whitish or yellowish dots, the presence of a cobweb on the stem. To cope with colonies of ticks, use drugs "Apollo", "Neoron". Instead of using chemicals, you can make an infusion of a liter of water and 20 g of dandelion or garlic cloves and spray the plant.
Why leaves turn yellow: violations of the rules of care
Petunia has delicate flowers and looks very attractive. However, sometimes the plant begins to wilt.
Violation of watering rules
Petunia leaves change green to yellow color, the stem softens when it is affected by rot, which occurs when moisture stagnates. If the plant begins to wilt, you must:
- Cut off dried shoots.
- Spray the flower with a fungicide.
- Thoroughly loosen the ground.
You should try to water the plant with warm water, but not abundantly. The soil should not get wet.
Temperature violation
Petunia comes from warm regions, but an adult plant in a flowerbed normally tolerates a cold snap and even slight frosts, but does not tolerate sudden changes in weather, prolonged rains. Flower seedlings develop well at 16–20 ° C, at temperatures below 13, the leaves begin to turn yellow, and growth stops.
Lack of iron
Petunia is demanding on the composition of the soil. With an insufficient amount of trace elements, the flower loses its decorative effect. To fill the deficiency of nutrients, fertilizers are applied to the ground. With a lack of iron, the leaves of the plant curl, turn yellow, decorativeness and the number of buds deteriorate.
Proper care of petunia
The South American guest is an unpretentious plant, but if you do not take care of it, diseases develop, pests attack.
Treatment of petunia with folk remedies
When yellow leaves appear, the bush is treated with copper sulfate, adding a little crushed soap to the solution. If irrigation is disturbed, fungi are activated to prevent them from multiplying, petunia is sprayed with potassium permanganate for 5 days. Copes with pathogenic microorganisms with a warm composition, which is prepared from 2 tablespoons of soda, 5 liters of water and soap. When the leaves wilt, petunia is treated by combining a liter of fermented milk whey with a bucket of liquid.
To prevent powdery mildew, an ornamental plant is sprayed with a spray bottle, filling it with horsetail infusion. Furacilin helps to cure petunia from disease. To do this, 10 tablets are dissolved in a bucket of water. Mullein, infusion of garlic and mustard are used to spray the flower.
Chemical treatment
If the means used by the people turned out to be ineffective, the plant continues to hurt, the leaves dry and the buds crumble, you need to get rid of the affected shoots and spray the flower with fungicides:
- "Amistar extra";
- Fundazol;
- "Bogatyr";
- "Acrobat";
- "Topaz".
When purchasing a drug, you need to carefully read the instructions, not every remedy heals all diseases.
When whiteflies, aphids, thrips appear, biological preparations "Aktofit", "Fitoverm", systemic insecticides "Intavir", "Desis-Profi", "Calypso", acaricides "Aktellik", "Nurell" are used.
