Abstract:  Population monitoring is an important step in population prediction and decision making of pest management. Compared with other labour-intensive sampling survey of different developmental stages and host damage levels of insect pests, semiochemical-based monitoring is simple, labor-saving, low cost, species-specific, sensitive under low population density and can be used in large scale. The applications of semiochemicals include three aspects: (1) detection of insect distribution and the species in certain area; (2) monitoring of the occurrence period of insect pests; and (3) monitoring of population levels or the damage degree. The reliability of the first two aspects is positive, while the third aspect is complex and controversial with both positive and negative examples. In this article we analyzed the existing application researches of semiochemicals in pest monitoring in China and other countries and explored the way to make the monitoring and prediction more reliable. There are many factors which influence the monitoring of semiochemials and forecast of population density, such as the component, composition, dose and releasing rate of semiochemicals, the type and design of traps in the field, the biology, population dynamics and phases of monitored species, field conditions e.g. biological factors including host species, species composition, host age, host density and so on, and abiotic factors like weather), damage estimate method, the prediction model used and the modeling method. Based on the study and analysis to make the semiochemical-based monitoring reliable, one should use correct composition and proportions of semiochemicals, appropriate dosage, and stable and persistent release rate of the semiochemical carriers. One also needs to choose a unified trap type, setting method and density. In addition, population level or host damage degree estimating method and prediction models should be taken based on the studies for a particular pest species and its environment so as to form the systematic monitoring standard and procedure. Semiochemical-based pest monitoring is reliable if a rational monitoring protocol is made according to the characteristics of a particular species and its environment.

Key words: Semiochemical, pheromone, population monitoring, population prediction, pest management