Damage And Control Of Rust(Melampsora Apocyni)to Luobuma In Altay Prefecture

Wild and cultivated Luobuma?Apocynum venetum,Poacynum apocyni and Poacynum hendersonii?in Altay,Xinjiang were chosen for a field experiment in the study.From the year 2016 to 2018,we investigated the occurrence of rust and factors that impact the epidemic of the disease,assessed the effects of the rust on aboveground biomass and quality of the cultivated Luobuma,and evaluated 12 fertilizer applicationtreatments and mixture of 2 chemical fungicide for rust control,the results are as follows:1.From 2016 to 2018,the rust incidence of wild and cultivated Luobuma in Altay,Xinjiang ranged from 27.12%to 87.29%,58.13%to 68.19%and 4.17%to 69.58%,respectively;The rust index were 7.73-57.37,28.43-40.26 and 3.25-37.40,respectively.The disease generally occurs in late May or early June,and tends to increase with the growth season.After reaching the peak,the degree of rust disease was slowed down or stabilized.Rust occurrence was closely related to environmental factors,it was significantly positive correlated with rainfall?P<0.05?and air humidity?P<0.01?and significantly negatively correlated with plant diversity?P<0.01?and temperature?P<0.01?.2.Under severe rust occur,the biomass of Eco-RSM leaves was reduced by 14.52%to 29.21%,and the content of total flavonoids was reduced by 32.50%to 36.53%?P<0.001?.When the severity of rust was grade 4 or above,the contents of 16 amino acids in two ecotypes were decreased significantly?P<0.05?.Rust could also affect the metal element content in the leaves of the Luobuma.When the severity was grade 4-5,the Ca content in the Eco-RSM leaves was decreased by 10.68%to 62.15%respectively?P<0.05?.Content of Ca and Cu in Eco-GSF leaves were increased by 26.34%to 121.69%and 98.65%to 412.27%,respectively?P<0.05?.3.Fertilizer treatment could control the occurrence of rust in A.venetum.N₂P₂?urea 75 kg/ha+NH₄PO₃ 105 kg/ha?and the organic fertilizers of Jinshibao had prevention effect,which decreased rust incidence by 2.78%-24.63%,and rust occurrence could be delayed by up to 20 days.4.The incidence of rust was reduced by 3.45%-40.60%and 32.56%-51.18%on the 7^th and 13^thh days after spray the mixture of triazolone and trimetazolone?P<0.05?.On the 6^th,10^th and 16^th days after the spraying,the residual amounts of traidimefon and chlorothalonil were 1.17 and 1.74 mg/kg,0.27 and 0.63 mg/kg,and 0.06 and 0.14mg/kg,respectively.According to National Standard GB 2763-2016,the maximum residue limits of traidimefon and chlorothalonil in teas were 0.05 mg/kg and 0.05-5mg/kg respectively,so the fungicide residues was within the national standard in the more than 16 days after application.