<p>Mowing is an effective weed-control method. Recently, the development of mowing robots has reduced the labor required for mowing. However, frequent mowing of cultivated land and surrounding areas may lead to the spread of Poaceae weeds, which serve as breeding sites for spotted rice stink bugs—a major rice cultivation pest in Japan. In orchards, the growth of grass weeds from spring to summer provides an ideal breeding site for rice stink bugs, which then migrate to rice paddies during autumn. In this study, we propose the use of trampling as an alternative to mowing and evaluate the effectiveness of a trampling robot in controlling Poaceae weeds that grow from spring to summer in orchards. The use of a mowing robot and conventional manual mowing induced a vegetation dominated by Poaceae weeds, which are major host plants for rice stink bugs. In contrast, the trampling robot effectively controlled grass weeds and promoted the growth of clover-dominated vegetation. Because clovers are often used for undergrowth management in orchards, the use of a trampling robot in combination with clover vegetation is considered an effective weed-control strategy.</p>