一、发病原因 该病发生要求较高温度,较高湿度,特别是低洼水浇地,灌水多造成干基水湿条件使栽植过深、栽植密度过大、嫁接口和干基接穗部被埋入土中的植株均最易发病。在品种之间以苹果梨最严重,其次是锦丰、早酥、鸭梨等,此病主要发生在1—7年生幼树,病斑主要在干基接穗部分。 First, the cause of the disease The occurrence of the disease requires higher temperatures, higher humidity, especially low-lying irrigated, irrigation and more water-based conditions resulting in dry planting too deep, planting density is too large, grafted mouth and dry-based ear is buried The plants in the soil are the most susceptible to disease. Among varieties, the most serious was apple-pear, followed by Jinfeng, Shangxu and Yali pear. The disease mainly occurred in 1-7-year-old saplings and the lesion was mainly in the stem-based scion.