In addition to the harm caused by cypress, cypress rust commonly occurs in China. It also directly leads to the victimization and reduction of many fruit trees.
First, the bacteria
1. The host of pear rust fungus is the cypress cypress, and European cypress, cypress, dragon cypress, etc., among which cypress, European cypress and Cypress are most susceptible. The main hosts are pears, sticks, seaweeds, papayas, and hawthorns.
(2) Yamada Rust It has harmed cypress, Xinjiang cypress, European cypress, Greek oyster, axillary, cypress, and cypress. The host is apple, sand fruit, jellyfish and so on.
Second, the symptoms
1. After the pear rust fungus was infested, pale yellow spots initially appeared on the needles, leaf bracts or twigs, and then slightly swollen. Between February and March of the following year, the skin gradually emerged as a single or a few conical horns, reddish-brown to brown, which is the fungal winterspores horn. The phosporus antralus swells into a lingual colloidal block in the event of rain. It is orange-yellow and shrinks into a plastic block when dry.
2. After the rind of Yamada Rust was infected, a tumor with a diameter of 3 to 5 cm was formed on or around the branchlets. The diseased area was yellow and the surface was flat at first. By spring, the uplift of the center of the bacillary dysentery broke, revealing a brownish-brown coronal phosporus horn. The phosporus horn, in the form of colloidal petaloids, swells with water. When cypress suffers from serious damage, the branchlets die.
Third, the incidence characteristics
1. Pear rust is overwintering with perennial mycelium in the diseased part of Sabina. After germs invaded Sabina, symptoms appeared from October to December, showing yellow spots. By the second and second year of the year, the symptoms were obvious, and the teliospores penetrated the host epidermis and were exposed. Winter spores mature gradually after late March. When the temperature is above 5°C, the teliospore angle is gelatinized in the presence of rain, and the winter spores germinate the yellow powdery basidiospores. It cannot endanger the cypress, but it can only harm the host host, such as pears, etc. Spores and rust spores can no longer harm pears, etc., and in turn invade young leaves or shoots of cypress, forming a new cycle of infection.
2. The Yamada Rust is overwintering on the cypress with mycelium in the fungus, and the brown phosporus horn is formed in late spring. It bulges in the event of rain or when the air is moist, and germinates a lot of pale yellow-brown basidiospores and spreads through the wind. Transfer to host trees such as apple trees, invading leaves, petioles, fruits and shoots, forming spores and rust spores. The rust and spores ripen and drifted to the cypress on the wind and invaded the cypress twigs.
Fourth, control methods
1. Strengthen cultivation management
2. Exterminate the bacteria source In winter, the bacterium and severe disease branches on the cypress were cut and burned.
3. The fruit tree spray interrupted the main circulation. The spread of the two rust species is generally 2.5 to 5 kilometers. For the apple trees and pear orchards that are close to the cypress, they should be in the young fruit period after the apple tree is sprouted, and the buds should be in the bud period until 25 days after the exhibition. Spore propagation, infection, spraying protection during the prosperous period. Can be used lime times 160 to 200 times more Bordeaux liquid or 25% triadimefon WP sprayed 1500 times, have better control effect.
4. Cephalotolous spraying In mid-October to the end of November, Cephalotaxus was sprayed with 0.3% sodium pentachlorophenol to kill the rust spores that were transmitted to Cedarwood, such as 0.3% pentachlorophenol sodium mixed with 1 degree lime sulfur. Better results. In mid-March, spraying 3 to 5 degrees lime sulfur once or twice, or 25% triadimefon 1000 times, can effectively inhibit sporulation of phospores.
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