You Are Here: Management Updates 2002 Archive November 8, 2002

Date: November 8, 2002
Category: Nematodes
Subject: A Big Year for Nematodes

2002 was one of the busiest years on record for number of samples and high nematode populations. We processed 256 soil samples and 63% had one or more genus of nematode over threshold.

The most common problem nematodes were stunt (Tylenchorhynchus) ring (Criconemella) and lance (Hoplolaimus). Forty percent of the samples had root-knot but only a few were over threshold. This is misleading because root-knot juveniles extractable from soil are scarce during summer and there is no way to estimate root populations.

Some of the unusually high populations included (per 100 cc of soil):

• 28,000 spiral
• 3,500 root knot
• 440 sting (from Alabama)
• 1,040 cyst juveniles with 232 egg-bearing females
• 14,900 stunt
• 14,420 lance
• 6,340 ring
• 1,848 sheath
• 104 needle
• 116 stubby root
• 2,180 lesion

The two worst combinations in a single green were:

• 13,520 stunt + 3,220 lance + 4,640 ring
• 14,420 lance + 11,700 stunt

High nematode populations most probably resulted from high survival rates during the milder than normal winter of 2001-2002. Typically, populations of nematodes are greatly reduced in the winter. Regardless of conditions this winter, courses that experienced high counts of nematodes this year should take soil samples in June and July to monitor soil populations. Those that had root-knot, even very low numbers, should have assays done in April.

- Submitted by: Dr. Rob Wick