You Are Here: Management Updates 2005 Archive April 21, 2005

Date: April 21, 2005
Category: Nematodes
Subject: Sampling & Assessment: Endoparasitic vs. Ectoparasitic Nematodes

During spring, visible injury on golf greens is not due to activity by plant parasitic nematodes. Populations are at their lowest point but they will steadily increase in numbers until about mid-July, or later. However, if you had a diagnosis of root-knot nematodes during the growing season last year, this is a good time of year to do an assessment, and a good time of the year to treat. Root-knot nematodes are endoparasitic meaning that they enter entirely into the root system. In the spring, juvenile root-knot nematodes, and newly hatched juveniles are still in the soil, and we can pick them up in a soil assay. Once June rolls around most of the juveniles have  moved into the roots and  we are largely unable to recover them and estimate their potential effect on turf. Also, once the root-knot nematodes are inside the roots, they are protected from any chemicals or materials designed to  reduce their numbers. On the other hand, ectoparasitic nematodes such as stunt, ring, spiral and lance, remain outside the roots and they can be recovered and counted in the lab year around. Assessment of ectoparasitic nematodes is best done during June and July.

Submitted by: Dr. Robert Wick

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