山西省大同市早播饲用燕麦叶部真菌病害病原鉴定及影响因素分析

Identification of fungal diseases and factors influencing disease index in oat(Avena sativa)crops in the Datong region of Shanxi Province,China

山西省大同市是我国饲用燕麦的主产区之一,叶部真菌病害已成为限制其生产的主要因素,但目前尚不清楚病害种类及病原。此外,早播燕麦罹患病害产生的侵染源可能增加复种植物病害流行风险,阻碍燕麦可持续生产,迫切需要明确影响早播燕麦病害发生程度的主要因素,有针对性地制定防治措施。鉴于此,利用形态学特征和致病性测定对大同市天镇县的早播饲用燕麦种植田发现的叶部真菌病害进行鉴定,并且分析了收获期病情指数和病害影响因素之间的关系。结果表明:早播饲用燕麦共发现3种由真菌引致的叶部病害,分别为禾谷炭疽菌(Colletotrichum cereale)引致的叶枯病,燕麦内脐孺孢(Drechslera avenacea)引致的条斑病和禾柄锈菌燕麦转化型(Puccinia graminis f.sp.avenae)引致的秆锈病。不同种植和管理方式下,饲用燕麦叶枯病、条斑病和秆锈病均有不同程度发生,病情指数均值分别在1.9~5.6,1.0~6.2和0~0.9。相关性分析表明:喷灌是导致条斑病发病严重的主要因素,豆禾混播能降低饲用燕麦叶枯病的发生程度。此外,土壤速效N和速效K含量也能影响叶枯病和秆锈病的发生。建议牧草种植者在生产饲用燕麦时,采用合理的灌溉和施肥模式,推广牧草混播等种植技术,使用低毒高效杀菌剂对早播饲用燕麦进行病害防治,保证饲用燕麦产业的可持续发展。

The Datong region in Shanxi Province is one of the main areas of oat production in China.Fungal diseases of oat leaves have become a major limiting factor reducing yield,but the identities of the pathogens remain unclear.In addition,the infection of early-sown oat crops may provide a source of inoculum that increases the risk of disease occurrence in later-sown crops,so hindering the sustainable production of oats regionally.Thus,there is an urgent need to clarify the main factors affecting the fungal disease intensity(disease index)on early-sown oat crops,in order to assist with development of disease control measures.Morphological characteristics and pathogenicity determinations were used to identify the pathogens causing fungal leaf diseases in early sown oat fields in the Datong region.A relationship between the disease index at harvest and the factors affecting disease index was developed.Three fungal diseases were found in early-sown oats:leaf blight caused by Colletotrichum cereale,leaf streak disease caused by Drechslera avenacea,and stem rust caused by Puccinia graminis f.sp.avenae.The disease index of leaf blight,leaf streak and stem rust under different planting and management patterns varied;the disease index(on a scale of 0-100)ranged from 1.9 to 5.6,1.0 to 6.2 and 0 to 0.9,respectively,for the three detected fungal pathogens.Correlation analysis showed that sprinkler irrigation is the main factor implicated in serious incidence of leaf streak disease.Mixed species sowings can reduce the disease index of leaf blight in oat crops.In addition,high/low levels of soil available N and K are often associated with increased incidence of leaf blight and stem rust.We recommend that forage growers should use rational application of fertilizer,avoid sprinkler irrigation mode,and follow extension techniques for mixed species sowings in oat production.We strongly recommend the use of low-toxicity,high-efficiency fungicides to control disease in early-sown oat crops to ensure the sustainable development of the commercial cultivation of oat crops in the Datong region.