Control methods for round spot root rot in hawthorn

Round spot root rot is one of the important causes of hawthorn tree death.

1. Symptoms: the fibrous roots first turn brown and die, and reddish-brown round lesions form around the base of the fibrous roots. In severe cases, the lesions merge, and the rot penetrates deep to the xylem, causing the entire root to turn black and die.

2. Transmission routes and disease conditions: the pathogen causing this disease can live saprophytically in the soil for a long time. When the hawthorn root system grows weak, the pathogen invades the roots and causes disease. Orchards with heavy, compacted soil, excessive salinity and alkalinity, long-term drought and lack of fertilizer, severe soil erosion, severe alternate bearing, and improper management have more severe disease.

3. Control methods (1) Strengthen cultivation management, enhance tree vigor, and improve disease resistance. Improve orchard drainage and irrigation facilities so that watering is possible in drought and drainage is possible in waterlogging; improve soil structure and prevent soil erosion; orchards with conditions can carry out deep plowing. During the growing season, cultivate and weed in time and preserve soil moisture; prune rationally, regulate the fruit load of the tree, and avoid alternate bearing; orchards with poor fertility should grow more green manure crops for burying, and adopt formula fertilization techniques. (2) Treat diseased trees. In spring and autumn, scrape away soil to expose the roots, scrape out the diseased parts or cut off diseased roots. During the root exposure period, avoid irrigation water entering the tree pit or rain soaking it, expose the roots for 7-10 days, and after scraping off the lesions, drench the roots with Bordeaux mixture or 5 Baume degree lime sulfur or 45% crystalline lime sulfur 30-fold solution. You can also apply 50% carbendazim 1000-fold solution or 50% lijiing wettable powder 300-fold solution to the wounds, and the control effect is also relatively good.