杨叶霉斑病又称蝇粪病。此病在国内仅河南、陕西有过报导。近年来在我省晋中地区的一些苗圃广为发生,为害严重。以太谷县苗圃为例,1978年,群众杨被害率达90%以上,79年达100%。从一年生插条苗,2—3年生幼树,至10多年生大树都可受害,尤其对1—2年生幼树为害甚重,造成早期落叶,直接影响苗木生长和木质化,从而降低苗木质量。我们于1978、1979两年对此病进行了初步观察和防治试验。一、杨树霉斑病的症状主要为害叶片。受害叶片上仅1、2个或少数几个病斑,病斑近园形,有明显边 Yang leaf spot disease also known as fly feces disease. The disease is only reported in Henan and Shaanxi provinces. In recent years, some nurseries in the Jinzhong area of ​​our province have been widely reported, causing serious damage. In the case of the Taigu nursery, in 1978, the masses were killed more than 90% and 79% for 100 years. From year-long cuttings, 2-3 year-old saplings to 10-year-old trees can be damaged, especially 1-2 year-old saplings are very serious, resulting in early deciduous, a direct impact on seedling growth and lignification, thereby reducing seedling quality. We conducted a preliminary observation and control test on the disease in 1978 and 1979. First, the symptoms of poplar mycosis is the main damage leaves. Affected leaves only 1, 2 or a few lesions, lesions nearly circular, with obvious edge