1. Anatomy structure of root, stem and leaf of dayflower ( Commelina communis L. ) was studied, There are six xylema in root.

2. Dayflower was controlled effectively wh en moisture was less than 13% and there was sunshiny in future days.

3. As a kind of annual late-spring weed, dayflower(Commelina Commw2is L), which existed mainly in dry land, such as soybean, wheat and corn, was very difficult to control.

4. With rapid increase of the tolerance to imazethapyr, the key period of spraying dayflower was as early as 3-leaf stage.

5. The test had studied the proper time and method of controlling dayflower.

6. The effects of different soil water content, depth of sowing and dose of fomesafen on dayflower emergence were studied.