FARMERS RICE SEED MANAGEMENT-PRACTICES AND RESULTING WEED SEED CONTAMINATION IN THE PHILIPPINES

Seeds of 20 weed species were found to contaminate rice (Oryza sativa L.) seed from farmers in Nueva Ecija, Philippines. Most farmers select ed patches in fields for rice seed. Hand weeding and winnowing after m achine threshing were done to reduce weed contamination. In spite of s uch practices, seeds of Echinochloa spp., Ischaemum rugosum Salisb., a nd, to a lesser degree, various sedges remained as rice seed contamina nts in most samples. I. rugosum is a recent arrival and has been expan ding in terms of area infested, Farmers thought that Echinochloa spp. spread via contaminated rice seed and that I. rugosum seed was largely soilborne.