Study of Leaf Spot of Phleum pratense and Its Harm in Min County,Gansu Province
Phleum pratense is a perennial tufted grass that serves as a valuable forage crop due to its highly cold and moisture resistance,high quality,and high yield.Disease is a significant factor limiting the production of P.pratense,and systematic research on P.pratense diseases was lacking.In this study,we investigated the dynamic of P.pratense leaf spot disease caused by Cladosporium phlei,and also conducted the disease damage loss assessments.The results showed the disease mainly occurred in the middle and late growth stages of cattail grass.The highest incidence rate in the field was 83.2%,and the disease index was 42.2.The disease signifi-cantly impacted the yield and quality of P.pratense,resulting in a 50.6% reduction in fresh weight,35.2% reduction in zinc and 58.1% reduction in chlorophyll content.The contents of phenylalanine,isoleucine,aspar-tic acid,alanine,glycine and arginine were decreased significantly by 42.5%-67.5% .In addition,dry weight,crude protein content and chlorogenic acid content were lost by 34.0%,45.7%,and 23.3%,respectively.In summary,this study found that the leaf spot disease of Phleum pratense is an important disease affecting the pro-duction of Phleum pratense in Min County,and there is an urgent need to develop prevention and control tech-nologies.