Prevention and control of edible fungus diseases and orchid nematode disease

The nematode of orchid is a parasitic disease of Orchidaceae. It belongs to the phylum Nematoda, Nematoda, Nematodidae. The adult nematode of orchid is linear and long cylindrical in shape, pointed and thin at both ends, unsegmented, and consists of three germ layers with protoplast cavities. The nematode eggs are very small, the smallest is only 1 micron. The eggs that fall into the plant material absorb water and expand when the plant material is wet, and after the larvae overflow, they invade the root quilt tissue, move upward along the plant to the leaf or mesophyll tissue or the storage tissue of the root to absorb the nutrients of the orchid plant, stimulate the cortical cells and cause the formation of galls. After the adult population of nematodes matured, they mated and laid eggs in the galls. After the eggs in winter hatched into larvae, they stayed in the galls. When the earth returned to spring in the coming year, the larvae would spill out the gall shell, washed by Rain Water and irrigation, fell into the plant substrate, and then re-infected.

In the plants with this insect disease, the insect began to migrate to the root integument and leaves of the host in early summer, invading from stomata or water pores, resulting in phosphorus yellow dots on the leaves, and the bottom surface could be seen. After the beginning of autumn, the yellow spot became a thick leathery scab gall, showing a round shape. A fixed-point rough bend appears in the root, and then a flat nodular gall is formed. When the root is degenerated and dried up in winter, the living galls remain in the plant or culture medium. When the spring temperature rises to 18: 22 ℃, the gall larvae overflow and infect other roots and new individuals in the same basin. It happens so repeatedly. For the orchid plants parasitic with nematodes, most of the leaves become thickened and hard, and there are sores and demons, the tillers are abnormal, and most of them can not draw flowering stems.

The prevention and control of orchid nematode disease should give priority to prevention. 1% potassium permanganate solution can be used to rinse the substrate, rinse with clean water, and then use it after drying. When dividing the basin in winter and spring, the leaves with galls should be cut off, and the old roots and roots with galls and dried bracts should be cut off and burned. When it is found that there are round small yellow spots in the leaves, internal absorbent insecticides such as Mudan should be applied immediately; spray 3% on the leaf surface and back. Citric acid absorbs hexazine solution or 800 times rotenone solution, or sprays with 4% Shandao annual water agent; you can also use the above solution to drench the plant material to make the orchid root adsorb.