How to prevent and control stem rot in flowers and nursery stock? A detailed practical guide

Stem rot in flowers and nursery stock is a disease caused by fungi of the order Sphaeropsidales in the class Deuteromycetes, and integrated control measures should be adopted:

First, choose land with a low groundwater table and good drainage as the nursery; for container seedling raising, a pathogen-free soil must be used to prepare the growing medium; adhere to a crop rotation system and do not continuously grow the same type of nursery stock on the same plot of land.

Second, kill the pathogens. The stem rot pathogen is a soil-borne fungus that normally lives saprophytically in the soil. Before raising seedlings, dead branches, dead leaves and dry grass can be evenly scattered on the seedbed and set on fire, which can kill the pathogens in the soil. Alternatively, 25 kg of lime powder or 15 to 20 kg of ferrous sulfate powder can be applied per mu of nursery land to suppress the pathogens.

Third, apply decomposed fertilizer. Fertilizer should be mainly farmyard manure, supplemented by chemical fertilizer. Garbage compost, compost and barnyard manure may carry pathogens, so they should be piled for fermentation and fully decomposed before use.

Fourth, build a shade shed in the hot season, which can lower the seedbed temperature and reduce the incidence rate by more than 85%.

Fifth, improve the disease resistance of seedlings: timely cultivating and weeding, thinning seedlings and topdressing so that seedlings emerge uniformly and grow vigorously. Starting from the emergence stage, spray 50 to 75 kg of Bordeaux mixture per mu of nursery land on the seedlings, so that a protective film forms on the surface of the seedlings to prevent pathogen invasion. After disease onset, promptly remove diseased seedlings and spread lime powder around the holes of diseased seedlings to prevent spread.