In addition to pests, garden flowers infect diseases – both fungal and viral. In addition, flowering plants are prone to bacterial infections – bacteria remain on flowers for several years and can spread throughout the garden, transmitted from diseased plants to healthy plants by wind, water drops and insects. Why flowers get sick and how to treat them – read in this material.
Flower diseases powdery mildew and peronosporosis
Powdery mildew is the most common disease of garden flowers, caused by several types of pathogenic fungi.
The disease is characterized by the formation of a white or brownish-gray powdery coating on the surface of shoots, leaves, buds, twigs.
Affected leaves curl, sometimes fall off, shoots stop growing and, with a strong development of the disease, die off. This fungal disease of flowers spreads very quickly, affecting primarily young shoots and leaves. The causative agent of the disease overwinters on dead parts of plants.
How to treat this flower disease in the garden? Along with the creation of optimal conditions for the development of plants in the fight against powdery mildew, it is necessary to use special preparations of curative, eradicating and preventive action. These are Topaz and Skor. It is important not to “start” the disease and spray when the first signs appear. If necessary, the treatment with pesticides is repeated after two weeks. In the summer months, when the air temperature is above +22.. .+23 °С, good results are obtained by treating plants with garden gray, colloidal or “Tpobit”.
The intensity of the development of the disease of flowers, powdery mildew, somewhat restrains the spraying of plants with copper-containing preparations.
Downy mildew (peronosporosis) affects various plants, but of annual flower crops, it poses the greatest danger to tobacco.
The infection develops on the leaves: light yellow angular oily spots appear on their upper side, which subsequently turn brown, on the lower side.
As can be seen in the photo, the disease of flowers peronosporosis provokes the formation of grayish-purple plaque in places of spots, consisting of pathogenic conidia:
The spots gradually increase, merge, and the leaf dries out.
The causative agent of downy mildew persists in the remains of diseased leaves in the form of zoospores, which can be viable for up to six years. In moist soil, they germinate, and infection of tobacco seedlings occurs.
To protect against this disease, when planting letniki, it is necessary to return tobacco to the flower garden no earlier than six years later in case of illness of this crop in the previous year. Do not plant seedlings too densely. When sowing seeds in the soil of a flower garden or resuming plants from self-sowing, break through the seedlings in a timely manner.
How to treat flowers for this disease? When the first signs of the disease appear, it is necessary to spray the plants with Profit Gold twice with an interval of 10-14 days.
Heavily affected plants that have lost their decorative effect must be removed from the flower garden with their subsequent destruction.
Why flowers and remedies for diseases get sick
Fusarium is a plant disease that is caused by various species of the Fusarium fungus. This disease is most dangerous for annual asters , they get sick at any age. In diseased young plants, the leaves turn pale, droop and dry out. In adults, the lower leaves turn yellow first, then the whole plant.
Look at the photo – with this disease of flowers, the leaves curl and fade:
The stem at the root collar acquires a brown color, which gradually spreads upwards, and the stem often rots in the region of the root collar. In this case, the outside of the stem is covered with a pink bloom of spores of the fungus – the causative agent of the disease.
Infection of plants occurs through the roots. Penetrating into the vascular system and releasing toxic substances, the fungus disrupts the normal supply of nutrients and water to the plant. This is what leads to decay. The disease manifests itself faster on weakened plants. The disease is promoted by high air humidity and a temperature of more than 25 … 27 ° C.
The infection is transmitted through soil and seeds.
It is necessary to observe the correct alternation of crops , return to its original place no earlier than after 4-5 years. At the first signs of fusarium wilt, pull out and destroy diseased plants. The best remedies for flowers from this disease – solutions “Phytosporin-M” or “Maxima”. In the future, you need to increase phosphorus-potassium fertilization and periodically, until September, with an interval of 10-12 days to spray the plants “Abiga-Peak” or “Oxyhom”.
Diseases of flower leaves rust and spotting
One of the most dangerous diseases of flower leaves is rust and spotting.
Rust is a fungal disease that strongly affects calendula, antirrinum, asters and other annual plants.
Leaves and stems are affected. At first, light brown small pads (pustules) filled with summer spores appear on them. When the pads mature, the epidermis ruptures and a mass of brown spores dissipates from the pustules. Later, by autumn, the same leaves develop winter fruiting – flat orange pads filled with brown spores. They overwinter and germinate in the spring.
Spores are easily carried by the wind, sometimes over long distances, and, falling on the leaves, continue their development.
With rust, the leaves gradually wither and dry up. Plants lose their decorativeness.
Control measures:
High agricultural techniques promote the development of healthy plants, increase their resistance to various diseases, including rust. If rust on the plants still appeared, to treat this disease of flowers, you need to spray the plants with copper-containing drugs (“Abiga-Peak”, “Ordan” or “Oxyhom”).
Leaf spot occurs on many flowering plants and is caused by various types of pathogenic fungi. Distinguish gray, white, brown, brown, black spots. As a rule, the spots are first round, then oblong or angular with concentric zones, sometimes with a rim of a brighter color.
Gradually the spots increase in size, the leaves turn yellow and die prematurely. This weakens the plant, the buds do not develop well, with a strong development of spots stops flowering. Plant death is also possible. The development of the disease is facilitated by thickened planting, high humidity, one-sided nitrogen fertilization and other factors that cause the general weakening of the plant.
Measures control:
Do not allow the plants to weaken. Remove fallen and severely affected leaves. At the first signs of the disease, spray the plants with any copper-containing preparation (Abiga-Pik, Oksihom, Oxychloride of copper, Hom, Ordan, Bordeaux liquid, etc.). If necessary, repeat the treatment in 8-10 days, alternating drugs.
Viral and bacterial infections of flowers
Viral diseases of flowers have characteristic features by which they can be distinguished from others. Most often it is mosaic, curl and twisting of leaves, variegation and growth of flowers. Viruses get on healthy plants when cuttings, cut flowers and infect them. The main carriers of viral diseases are sucking insects (aphids, thrips, cicadas).
Measures to combat viral diseases of flowers – the destruction of diseased plants at the beginning of the disease, the fight against sucking insects.
Bacterial diseases of flowers. Bacteria are the smallest single-celled organisms that, under favorable conditions, multiply extremely quickly, affecting grown plants. Bacteria develop especially rapidly at a temperature of +20…+30°C and high humidity.
Bacterial diseases are transmitted from diseased plants to healthy insects, wind, water droplets and humans. Bacteria remain on roots, seeds and affected plant debris without losing viability for several years.
The most common bacterial diseases of summer plants are leaf spot, which differs from the fungal one by the presence of an oily halo around the spot.