Abstract: Based on the observation data of the wheat aphid occurrence in 1985-2007 in Liangzhou District of Wuwei,the emergence,peak period,the spatial and temporal dynamic changes of the wheat aphid population and meteorological factors affected wheat aphid population changes were analyzed. The results showed that the occurrence and damage of the wheat aphid increased generally. The annual aphid population development followed a logistic growth curve and was divided into increasing period from early April to mid May,accelerated increasing period from late May to late June and decelerated increasing period from early to mid July. The meteorological factors affected the aphid emergence period were the precipitation in March and the minimum temperature in early May,while the meteorological factors affected the aphid peak period were the precipitation in June,accumulative sunshine hours from mid May to early June and minimum temperature in late June. The meteorological factors affected the damage degree were the accumulative sunshine hours from late March to early April,minimum temperature in mid December and early January and atmospheric relative humidity. The heat and moisture conditions were the key meteorological factors affected the aphid population dynamic changes. The aphid population growth was positively related to the light-heat factors,such as the atmospheric temperature and sunshine hours,while it was negatively related to the moisture factors,such as precipitation and humidity. The forecast model established by statistical methods was with accuracy by 73%-82% for emergence period,peak period and damage degree.

Key words: Wheat aphids, Wheat aphids, Dynamic changes, Meteorological forecast