Teak and melina farmers’ perceptions of problematic weed species and management practices in Costa Rica

Abstract A survey was conducted among teak and melina growers across Costa Rica to assess their perceptions of problematic weed species and to document current weed management practices in forest plantations. A total of 180 farmers were selected from six provinces, yielding an 87% response rate. Results revealed that 47% of respondents had established plantations on formerly forested land, while 43% did so on previously used pastureland. Most farmers employed an integrated approach toward weed management that included manual, mechanical, and chemical methods. The most problematic species cited most frequently included coyol palm, jaraguagrass, orchid vine, raspa guacal, and arrocillo. Herbicide use was widespread, with glyphosate, metsulfuron-methyl, and paraquat being the most common active ingredients, typically applied singly, in mixtures, or sequentially. The findings reveal a heavy reliance on only three herbicides and highlight the need for targeted control of species in the Poaceae family and climbing vines. This work contributes valuable insights into weed dynamics in tropical forest plantations and emphasizes the need for region-specific and sustainable management strategies to mitigate potential productivity constraints and reduce reliance on herbicides.