Observation and Evaluation of Lawn Mythimna Separata in Chengdu

An observation made from 1992 to 2004 on lawn Mythimna separata in Chengdu region shows that these Mythimna separata are the offspring of the Mythimna separata immigrated.Their soaring appetite comes out in the middle July.Therefore,the best controlling time is the first ten-day period of July.There is a close relationship between occurrence frequency of Mythimna separata and moth trapping as well as stalk-bundle larvae trapping,and can be taken as an observation and evaluation factor which is simple and effective.