陕西省庙坪林场云杉锈病发生与防治OA

To clarify the current status of spruce rust(Chrysomyxa spp.)occurrence in Miaoping For-est Farm,Shaanxi Province,and to screen for effective control agents,field disease investigations and chemical control experiments were conducted from 2020 to 2024.The results showed that:(1)The severity of spruce rust was negatively correlated with the distance from the forest land to the alpine meadow wetland.The closer the distance,the more severe the disease.Within 0-20 m,the infection rate was 95.83％and the disease index was 61.20,while beyond 100 m,the infection rate was only 8.33％with a disease index of 2.35.In stands near the wetland,symptoms such as needle drop and dead tops were even observed.(2)All four tested agents—triadimefon,tebuconazole,thiophanate-methyl,and mancozeb—showed control efficacy.Among them,triadimefon and tebuconazole were the most effective,achieving control efficiencies of 77.19％and 78.72％,respectively,10 days after the second application.(3)From 2022 to 2024,an unmanned aerial vehicle(UAV)spraying protocol of"apply-ing tebuconazole in mid-May and triadimefon in mid-June"was implemented.In the severe disease are-a within 0-20 m,the disease index decreased from 61.20 in 2021 to 16.57 in 2024,with significant recovery of tree vigor and no recurrence of dead tops.This study clarifies the patterns of spruce rust occurrence in Miaoping Forest Farm,identifies highly effective control agents and application strate-gies,and provides a scientific basis for spruce rust management in the Qinling forest region.