Abstract:

Diseases， pests， weeds and rodents can be defined as organisms that detrimentally impact the ordinary life， production activities， and survival of human beings within constrained conditions. In the field of grassland conservation， harmful organisms mainly refer to pathogenic microorganisms， pests， noxious weeds， and rodents. Grassland pests are not only important components of grassland ecosystems， but also important factors threatening grassland production and ecological security. The harm caused by diseases， pests and weeds runs through the pre-plant production level， plant production level， animal production level and post-biological production level of the whole grassland agricultural ecosystem， and causes huge losses in various production stages， which seriously threaten the ecological security of grassland and the economic development of animal husbandry in China. Presently， research on the disease， pest and weed induced losses in grassland is characterized by fragmentation， with the associated assessment methods and models being less developed and systematic compared to those in the agricultural domain. Therefore， this study reviewed the domestic and international research on grassland disease， pest and weed loss assessment， and categorized the indexes， methods and models of loss assessment in four categories： diseases， pests， noxious weeds and rats， and briefly evaluated the advantages and disadvantages of different methods and models as well as their scope. This research aims to provide theoretical knowledge to underpin for grassland protection.

Key words: pest, loss, model, economic threshold