一、山楂褐腐病的防治 查明,在密植条件下,山楂褐腐病的致害性可增至80——90％。病兆于早春在花序周围的嫩叶上出现,同时在树体下层亦较常见。在叶片形成微红—褐色斑点,一经形成,便迅速扩大。在2—3昼夜通过脉管系统感染至短果枝群,破坏这些短果枝群,因而导致全 First, the prevention and treatment of hawthorn brown rot Identified, in close planting conditions, hawthorn brown rot can increase to 80--90%. Sickness signs appear in young leaves around inflorescence in early spring, and are also more common in the lower layers of trees. Reddish-brown spots formed on the leaves, rapidly expanding as they formed. In 2-3 days and nights through the vasculature infected to short fruit branches, destruction of these short branches, resulting in all