1、Farmers need to regularly remove pigweed from their fields to avoid it competing with the crops.

农民需要定期清除田地里的野莧菜，以防止其与庄稼竞争。

2、The spread of pigweed has become a major problem for gardeners in the area.

野莧菜的传播已经成为该地区园艺爱好者的一个主要问题。