Population Dynamics of Ectoparasitic and Endoparasitic Nematodes in North Carolina.

Sting nematode (Belonolaimus longicaudatus) and root-knot nematode (Meloidogyne spp.) are emerging problems for creeping bentgrass and bermudagrass putting greens in the transition zone. These nematodes cause severe putting green damage resulting in decreased playability. Sting nematode feeds on plant roots and causes severe damage at very low population numbers. Root-knot nematode is an endoparasitic nematode, feeding and reproducing within the turf root system and decreasing overall root function. However, little is known about either nematode’s population dynamics and soil movement throughout the year. A sampling study was initiated in 2014 to identify nematode populations numbers throughout the year, and to understand the vertical distribution of the nematodes within a putting green soil. Four golf courses were sampled throughout central North Carolina, and nematode samples were taken monthly at three different depths. B. longicaudatus populations were consistent across three golf courses, with numbers ranging from 40-250 nematodes per 500 cc. soil. Root-knot nematode was sampled at a single course, and numbers of stage 2 juveniles ranged from 20-120 nematodes per 500 cc. soil. For sting nematode, populations were primarily located within the top 10 centimeters of the soil during the winter, but the summer saw a population shift to the lower 20+ centimeters of soil. This was very different from root-knot nematode, where populations were localized within the top 10 centimeters throughout the entire year. Both sting and root-knot populations began to increase in April as temperatures start to rise. This shows very different population dynamics depending upon feeding tactics, with high variability between ectoparasitic and endoparasitic nematode species.