Understand how to cultivate edible fungi and what are the common parasitic diseases of flowers?

(1) fungal diseases are the most important types of flower diseases. Fungi are lower plants without chlorophyll and are invisible to the naked eye. It can not make its own nutrients and use mycelium to absorb nutrients in flowers. Fungal spores spread everywhere by wind, rain, insects, etc. The common fungal diseases of flowers are:

Powdery mildew: the pathogen attached to buds and tender leaves, appeared white mildew layer, the damaged leaves and tips curled, shrunk and deformed, the flower buds could not open normally, the spores spread with air flow, the temperature difference between day and night was the most easy to occur in a large area at 10 ℃, and spread most easily in the greenhouse. Such as rose, inverted Admiralty, plum blossom, impatiens, melon leaf chrysanthemum, Dahlia powdery mildew and so on.

Black spot: a common disease of flowers, the disease lurks in the soil, invades the lower leaves with the splash of Rain Water, and spreads upward rapidly. The injured leaves first appeared black spots, and gradually expanded into round and oval pieces. The diseased leaves are yellow and withered, which has a great influence on the growth of flowers. The disease usually occurs rapidly in the rainy season from July to August. Common are rose, chrysanthemum, peony, geranium black spot and so on.

Black rust: pathogen spore infection, began to appear small pale spots on the front of the leaf, gradually dilated into a slightly round process, the back of the epidermis ruptured to produce orange powder, scattered with the wind, a large area of infection. Subsequently, dark dark oval spots were formed on the leaves, and black powder was produced after the dorsal epidermis of the leaves was ruptured. In serious cases, the whole plant is infected from bottom to top, and the leaves are scorched and fall off early. The common ones are rose, iris, rose black rust and so on.

Seedling blight: seedling disease caused by Fusarium, Rhizoctonia and Pythium, characterized by rot, quenching, blight, etc., and the seedlings suffered the most within 20 days. Common are gladiolus, lily, begonia, carnation blight and so on.

Anthracnose: mainly harmful to leaves, but also to stems. One is that on the leaves, there are light brown or gray-white near-round spots with purplish brown or dark brown edges. This spot often occurs at the leaf edge or leaf tip, and there are black spots on it, that is, the conidium disk of the pathogen. In severe cases, it withered and blackened more than half of the leaves. Such as orchid anthracnose, is also common in Magnolia, rubber tree, cyclamen, hydrangea and other flowers; the other is in the stem to produce a round or near-round spot, showing light brown, its upper black spots. Such as cactus anthracnose, mildew season or autumn rain, is serious. Prevention and treatment: on weekdays, we should pay attention to the light transmission and ventilation of potted flowers, do not place too dense. When a small number of leaves are damaged, the diseased leaves can be cut off and burned, and in severe cases, 50% carbendazim wettable powder 500-1000 times solution or 50% topiramine wettable powder solution can be sprayed, which has a better control effect.

Soot disease: damage to the branches, leaves and fruits of many kinds of flowers and trees. The pathogen is a variety of fungi. Most of them are transmitted by aphids or shell insects. At the initial stage, dark brown mildew spots appeared on the surface, which gradually expanded to form a black soot-like mildew layer, which hindered the photosynthesis of the plant, so that the plant could not produce nutrients and withered and died. Prevention and treatment: aphids and shell insects should be prevented and treated first; if soot disease has occurred, Baume 0.3 degree stone sulfur mixture can be used in summer, 3 degree stone sulfur mixture in winter and 1 degree stone sulfur mixture in spring; carbendazim and topiramine can also be used in the above example.

In addition, there are root rot, leaf spot and so on.

(2) bacterial disease bacteria is a very small single-celled organism, which does not have the differentiation of vegetations and reproduction. It absorbs nutrients through the cell membrane and propagates by division. Bacterial infection is mainly transmitted through stomata, dense glands, wounds and other ways, generally through running water, wind and rain, insects, soil and residues of diseased plants. The common bacterial diseases are rose, root cancer of elm leaf plum and canker of citrus.

(3) virus disease virus is a tiny parasite. It can only be seen by electron microscope that the virus propagates only in living flower cells. The virus is transmitted by insects (mainly piercing and sucking mouthparts, such as aphids, red spiders, etc.), grafting, mechanical damage and so on. The symptoms are mosaic, etiolation, leaf curling, deformity, cluster dwarf, necrosis, spots and so on. Common are rose, begonia mosaic disease and rust fruit disease and so on.