6 ref. Sum. (En)

Pratylenchus coffeae is the phytoparasitic nematode most frequently found infesting yam (Dioscorea spp.) tubers affected by a dry rot called burn or burning in Jamaica; Scutellonema bradys has been encountered often and Hoplolaimus spp. twice. It appears that the dry rot injures or destroys primordia on yam planting material resulting in unthrifty plants or non-sprouted planting pieces hence poor stands in the field. Negro yam (D. rotundata) planting pieces were disinfested of P. coffeae by dipping in water at 50C for 40 min. or for 30 min. in a 2.500 ppm. Oxamyl solution or left undisinfested. The yam pieces were planted in plots artificially infested with or free of P. coffeae. After five and 11 weeks, there was no significant difference between treatments in numbers of sprouted yam pieces. At 11 weeks, vines borne by undisinfested planting pieces in P. coffeae-infested plots were shortest while the tallest vines had grown from disinfested yam pieces in P. coffeae free plots. Overall, plots planted with yam pieces disinfested by Oxamyl or hot water produced 22 percent and 19 percent greater quantitative yields of tubers respectively than those with undisinfested pieces. Tubers borne in P. coffeae-infested plots planted with undisinfested yam pieces showed highest levels of the nematode-related dry rot