Iditification Of Leaf Blight Of Platycladus Orientalis And The Field Efficacy Trials At Mausoleum Of The Yellow Emperor

This study explored leaf blight of Platycladus orientalis at Mausoleum of the Yellow Emperor in Yanan,Shaanxi province.Through isolating pathogens,determining pathogenicity,and identifying morphology and molecules,the pathogens of P.orientalis were confirmed.The control effect of fungicides were evaluated by field test.The results were as follows:1.The study showed that the pathogenic bacteria in leaf blight of P.orientalis at Mausoleum of the Yellow Emperor are Pestalotiopsis gracilis and Alternaria alternate.2.The result of pathogenicity test showed that both P.gracilis and A.alternate can lead the leaves of potted P.orientalis to disease symptoms.3.The field efficacy trials showed that 4 kinds of fungicides on P.orientalis leaf blight had different degrees of control effect,and the best performer was 45% tebuconazole-prochloraz EW which showed 80.35% and 84.03% control effect 10 days after the fourth spraying in two experimental fields separately,followed by 75% oxime bacteria-tebuconazole WG,80% tebuconazole WP and 25% prochloraz EW.4.The control results of 80% tebuconazole WP in large areas showed the best effect against leaf blight was on the young P.orientalis,which reached 75.49%.,followed by the ancient cypresses group in the temple(68.93%)and the control effect to ancient cypresses group along the road to Mausoleum of the Yellow Emperor(65.45%);the least effect(62.59%)was observed in the cypress group on hill.5.Compared the health status and comprehensive evaluation on the 19 ancient cypresses leaf blight disease in 2015 and those in 2016,it is clear that the health status at the Yellow Emperor Xuanyuan Cooper Temple mausoleum has significantly increased.The survey of the index of leaf blight showed that P.orientalis leaf blight in 2016 has achieved good control efficacy.