Phalaris and Tall Fescue Forage Production as Affected by Nematodes in the Field1

Abstract

AbstractNematodes are known to damage cool season perennial grasses, but effects on forage yields in the southeastern U.S. are unknown. Forage yield losses of two cultivars each of tall fescue (Festuca arundinacea Schreb.) and phalaris (Phalaris aquatica L.) were studied in a central Alabama field experiment on Augusta fine sandy loam (Aerie Ochraquult) soil. Yields were measured on untreated soil and on soil treated with methyl bromide (MB) or carbofuran nematicide (CN). Second‐year total forage yields of ‘Kentucky 31’ tall fescue were increased 107% with MB and 39% with CN above that of untreated soil. ‘AP‐2’ phalaris forage yields were increased 348% with MB and 172% with CN. Autumn and early winter production was affected most by the soil treatments. Sod populations of stubby root (Trichodorus christiei Allen.), stunt (Tylenchorhynchus claytonia Steiner), and lance (Hoplolaimus galeatus (Cobb) Thorne) nematodes increased by the second season and then declined. Populations of plant parasitic nematodes were decreased by MB and CN treatments. Nematodes destroyed grass roots at depths beyond 10 cm, and plant stand losses occurred during autumn drought. Nematode susceptibility contributed significantly to poor performance of tall fescue and phalaris on sandy soils. Other soilborne pathogens also may be a factor in causing root damage.These results indicate that nematodes are important in the persistence and production of phalaris and tall fescue on sandy soils of the southeastern U.S. Breeding for host plant resistance to nematodes will be necessary to extend the geographical range of these grass species.