ROOT REDUCTIONS OF ST. AUGUSTINEGRASS (STENOTAPHRUM SECUNDATUM) AND HYBRID BERMUDAGRASS (CYNODON DACTYLON × C. TRANSVAALENSIS) INDUCED BY TRICHODORUS OBTUSUS AND PARATRICHODORUS MINOR
Trichodorus spp. and Paratrichodorus spp. are considered damaging ectoparasitic nematodes on many crops. Two species commonly associated with warm-season turfgrasses in the southeastern United States are Trichodorus obtusus and Paratrichodorus minor. An earlier experiment indicated that T. obtusus might be the more damaging of these two species to St. Augustinegrass. Anecdotal field observation suggests that similar differences between these species might occur on bermudagrass. Glasshouse experiments were conducted to compare reductions in root length on 'Floratine' St. Augustinegrass and 'TifEagle' bermudagrass caused by T. obtusus and P. minor with each other and the unrelated ectoparasitic sting nematode, Belonolaimus longicaudatus. Each type of grass was grown in 1,500 cm3 clay pots that were inoculated with one of the three nematode species, or remained uninoculated as controls. Root systems were evaluated after 100 days, and root lengths and nematode population densities were compared among treatments. Trichodorus obtusus caused reductions in St. Augustinegrass roots when compared with the uninoculated controls in two trials, whereas P. minor caused reductions in St. Augustinegrass roots in only one trial. All three nematode species caused reductions in bermudagrass roots in two trials, but reductions caused by T. obtusus were greater than those caused by P. minor.
