The diseases and pests of chrysanthemums and how to deal with them
These plants have a fairly high immunity, especially with high agrotechnics. But with prolonged vegetative propagation in hothouses, damage to chrysanthemums can be caused by diseases and pests.
"Hair Loss" of Chrysanthemum Inflorescences
In this case, most flowers in the inflorescence are undeveloped, the inflorescences themselves are, as it were, "bald". This phenomenon is not typical for all varieties. The cause of the disease is a disturbance in nutrition during the laying of flower buds. The tendency to "baldness" of chrysanthemums is hereditary.
Control measures. Choose healthy and quality queen cells and fertilize plants in a timely manner.
On the leaves, light areas are formed, which later become dark brown. The leaves dry and crumble. Infected flower buds give ugly inflorescences, and the main inflorescences brown and wither. The causative agent is the nematode (Aphelenchoides ritzema bosi), or the filiform worm.
How to deal with nematodosis. Soil treatment with steam or formalin. Use cuttings of healthy plants. Do not plant diseased plants near healthy ones.
If damaged by thrips, white or yellowish, and later brown spots appear on the leaves, while the leaves are bent. Inflorescences are often affected, as a result, their decorativeness is reduced. Control measures. Spraying plants with drugs "Derris", "Intavir", "Bi-58" and "Actellik."
Powdery mildew (Oidium chrysanthemi)
A typical symptom of the disease is the formation on the leaves, stems and inflorescences of grayish-white mealy plaque. In this case, leaves die and the oppression of the plant. There is a disease in the absence of potassium-phosphorus fertilizers. Not all varieties of chrysanthemums are affected by powdery mildew.
Control measures. Do not plant the plants too thickly, gently water them, without wetting the leaves, and remove the affected leaves. Also it is necessary to process chrysanthemums in gray (3-4 times per summer), Topsin-M, Quadrase, Topaz and Bayleton.
Larvae of the May beetle
This pest eats the roots of chrysanthemums, as a result of which the plant dies.
How to deal with the larva of the May bug. Soil treatment with insecticide "Bazudin".
Gray rot (Botrytis cinerea)
Fungal disease, manifested in the autumn-winter period, during flowering and conservation of uterine plants. Rot rotates the entire aboveground part, covering the leaves and shoots with an ash-gray fluffy coating. On the inflorescences appear light brown watery spots that grow and form a brown rotten mass. The disease can also affect the rooted cuttings.
Control measures. Ventilating greenhouses, good lighting and normal temperature. Effective and spraying Topsinom-M, foundation, Horus, as well as biopreparations - "Trichodermin" and "Mycosan".
Slobbering a penny (Philaenusspumarius)
The second name of the pest is the leafhopper. In spring, larvae leave the overwintered eggs, which live on leaves and shoots under the guise of a foamy mass. The stalk is found in greenhouses on rooted cuttings. It feeds on the juice of plants, causing the appearance of yellow spots on the leaves and deformation of the inflorescences.
How to fight. Spraying plants with insecticides, such as "Fitoverm", "Fufan", "Confidor".
Spiderweb (Tetranychus urticae)
The tick infects chrysanthemums, which are grown in greenhouses. The damaged plants have a pale yellow color of the leaves, they form continuous whitish spots. Pest development is promoted by high temperature + 29-31 ° C and low humidity.
How to fight. In this case, it is recommended to treat chrysanthemums with systemic insecticides, for example, "Actellicom", as well as "Derris" and "Phytoverm".
Brown chrysanthemum aphid (Macrosiphoniella chrysanthemi)
It damages the leaves from the lower side, then they turn yellow, the flowers fall off, the buds do not open. Aphids are a carrier of viral diseases.
How to deal with aphids. Processing plants "Confidor", "Mospilanom", "Actellikom" and "Fitoverm", infusions of tobacco, yarrow and bitter pepper.
The disease manifests itself on leaves in the form of dark brown, almost black spots with a yellowish border. The spots merge and cover the entire leaf, the diseased leaves fall off. The causes of the appearance of Septoria - in the unilateral application of nitrogen fertilizers, thickened plantings and excessive humidity.
Control measures. It is necessary to limit watering, and also to remove and burn diseased leaves. The plants themselves are treated with systemic fungicides and Bordeaux fluid.
Note to beginners how to grow chrysanthemums
In autumn, chrysanthemums hit gardeners with bright colors and lush flowering. They should be transplanted and divided as early as possible - in October, so that they can take root before winter.
These plants prefer fertile soil with good water permeability. In November, preparing chrysanthemums for wintering, shorten the stems to 15-20 cm, cover the bushes and securely cover them with fir spruce branches. If it is not, plants can be thrown with any small branches, and on top of them with fallen leaves.
And remember that the shelter does not have to be made heavy, dense and not "breathing", if this is so the plants will begin to pound. And that chrysanthemums certainly did not become cold, initially acquire especially hardy varieties.
In the photo frost-resistant and hardy varieties of chrysanthemum
Grow cascading chrysanthemums
In April, place containers with rooted cuttings in a sunny place.
The main stem is tied to the pole, which should be pointed to the north and fixed at an angle. Every 7-10 days, pinch the side shoots, leaving only 2 on each one, but do not shorten the main stem.
Then, over time, the chrysanthemum will take on the form of a dense, well-branched shrub. Starting in August, gradually bend the main stem to the ground. In October, plants can be safely used to decorate facades - floral cascades of chrysanthemums will fall picturesquely along the walls of houses.
Below other entries on the topic "Dacha and garden - with their own hands"
- How to prepare chrysanthemums for wintering
- Annual chrysanthemums, variety and groups, planting and care
- Chrysanthemums - care, beautiful varieties, nipping and preparation for winter
- How to deal with pests and diseases of chrysanthemum
- Large-flowered chrysanthemums - care for flowers, growing and reproduction, photo
- Garden chrysanthemums (photo) - the pros and cons of growing, varieties and reviews
- Korean Chrysanthemum - planting and care. Varieties and their photos
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