Abstract: To understand the noctuidae pest dynamics of tobacco in Yuxi and to devise control strategy, sex pheromone traps were used to monitor their population dynamics for 3 years. The targeted pests included Spodoptera litura Fabricius, Agrotis ypsilon Rottemberg and Helicoverpa assulta Guenèe. In the winter, adult emergence of S. litura and A. ypsilon occurs in Yuxi, trap catches of the species ranked from high to low: S. litura, A. ypsilon and H. assulta. The peak periods of S. litura are during late April to late May and October to November, and minor peaks occur during June to September. The peak periods of A. ypsilon are during February to early March, mid-May to mid-June, and late December. And the peak period of H. assulta is during May to June. Trap catches were correlated to climatic factors, which show that the S. litura catches increased with rise in temperature, A. ypsilon catches increased with increase in sunshine duration and decreased with increases in relative humidity and the lowest temperature, H. assulta catches increased with increase in average temperature, lowest temperature and rainfall. To effectively control these noctuidae pests, sex pheromone traps should be established for S. litura after soil preparation and ridging or after transplanting of tobacco seedlings and until the middle of August (cutters harvesting period), for A. ypsilon from February to early March and until the end of May to early June (rosette stage), and for H. assulta after soil preparation and ridging and until the end of May to early June (7 d after topping).