Occurrence and control of stem rot of asparagus

1. Symptom characteristics asparagus stem rot mainly harms young bamboo shoots. The young bamboo shoots may be damaged after they are unearthed, and the young stems appear water-like amorphous disease spots, which expand around the stem, resulting in stem tissue disintegration and decay, resulting in the death of young bamboo shoots. If the disease is mild, even if it does not wither and die, its growth potential is greatly reduced, the aboveground stems and leaves are weak, the young stems are weak, and the yield is low. 2. Pathogen and characteristics of asparagus stem rot is caused by Pythium infection of the subphylum Pythium. The pathogen is also a kind of soil habitual fungus, which survives the winter with the remains of mycelia and oospores in the soil and saprophytic life in the soil. In the following year, the overwintering oospores can directly germinate germ tube to infect the disease, or they can germinate and produce sporangia, and zoospores can be used as the primary inoculum to infect the disease. Irrigation water and Rain Water are the main ways of transmission of pathogens, and secondly, pathogens can be transmitted by the application of soil fertilizer. A rainy year or season is conducive to the disease. Low-lying tidal wetlands, clayey soil frequently occur. There is still a lack of investigation on disease resistance among varieties. Third, prevention and control methods 1. In the areas where the disease often occurs, pay attention to the regulation of planting land drainage and irrigation system, drip irrigation can be used under certain conditions, flood irrigation should be strictly prevented, and ditches should be cleared in time to reduce dampness after rain. The clayey and heavy soil should be gradually improved by mixing sand or adding organic fertilizer to enhance soil permeability and root activity. The low-lying and moist land is cultivated with high border and deep ditch, and measures such as digging ring field ditch and cross ditch are taken to reduce the groundwater level. two。 Spray protection should be strengthened during the emergence period of young bamboo shoots. According to the requirements of no disease early prevention and early treatment, spray 30% copper oxychloride suspension agent (600 times liquid) or kill suspension agent (800 times liquid), or 25% metalaxyl wettable powder (600 times liquid), or 65.5% Prik water powder (600 times liquid), or 64% poisonous alum wettable powder (500 times liquid), 3 times 4 times, once every 5 ~ 10 days. For a small number of newly diagnosed mildly diseased plants, the spread of the disease can also be controlled by spraying young stems (50 times the liquid of the above chemicals), or mixing flour into a slurry, or adding irrigation to control the spread of the disease.