Control of Pratylenchus scribneri on Spearmint, Mentha spicata, with Nonfumigant Nematicides

Granular formulations of the nonfumigant nematicides carbofuran, fenamiphos, oxamyl, and terbufos were applied to spearmint, Mentha spicata L., heavily infested with Pratylenchus scribneri Steiner in greenhouse pots. Carbofuran, fenamiphos, and oxamyl were applied at 5.6 and 11.2 kg/ha and terbufos at 11.2 kg/ha. All of the nematicides greatly reduced nematode populations, with fenamiphos being the most effective, followed by terbufos. Foliage yields of the first four harvests of the mint from both rates of fenamiphos were not significantly different from those of the uninfested check. However, yields of the fifth harvest from both fenamiphos treatments were significantly less than for the check, and nematode injury symptoms were present. Similar results were obtained for terbufos applied at 11.2 kg/ha. Total foliage yields for the fenamiphos and terbufos treatments were not significantly less than for the uninfested check. Both rates of carbofuran and oxamyl were less effective than