Nematodes creating difficulties on Greens.

I am sending out this blog for the membership at IHCC in an effort to convey information regarding the serious problem that we have with a huge (more than 12X the threshold level) Nematode population in our original push-up style greens.

 In the last month or so, we have been experiencing some difficulties with the turf on a few of our greens.  At first the signs were wilting turf, but conditions for that were not typical, so it raised a caution flag.  We treated the greens with wetting agents and we are on a strict preventative program for a turfgrass diseases and insect problems, so the areas of concern were confusing.  We noticed that one variety of bentgrass was taking the hit far worse than any other grass on the greens.

These three photographs are from the 4th and 18th greens and are representative of the damage we are seeing not only there but on a few of the old push-up soil original greens.  Our newer 4 greens are in excellent condition and are not showing any signs of this damage.

On July 8th we sent a soil sample to the Plant Diagnostic Laboratory at Rutgers University.  By doing so we wanted to confirm that this issue was not related to a turf disease and that our preventative plan was working.   Samples were sent via express mail and we had results inside of 24 hours from the lab.  They stated the following: "There were no active insects, diseases, or mites identified on this sample.  There was no evidence of active Pythium (or other diseases), no yellow tuft, no bacterial wilt.  special tests for Rhizoctonia and Pythium were negative.  There were no signs of fairy ring or snow molds.  Based on our observations the poor performance of the grass is due to cumulative effects of environmental and cultural stresses.  There is also a huge nematode population in this green, which could very well account for the damage we see.  do everything you can to reduce stress and stimulate new rooting."

What we learned from this was that our preventative program for turfgrass diseases is on the money, clean as a whistle.  But we now have a major issue with a problem that is very difficult to treat, and most certainly here on Long Island, where we have some of the most strict regulations in the United States.

We immediately backed off of any process that leads to more stress on the turf...for example excessive mowing and rolling.  We have begun to make applications of a bacillus product that helps to protect roots from further damage, but our roots have been extremely compromised already.
Fortunately, we have caught a break with the weather and the slightly cooler evenings and less brutal daytime temperatures have helped us quite a bit.    You will recall that in the excessive heat of 2013, we had a similar situation, and the 11 days over 90 degrees hammered the greens, although again not our newer greens.  The problem there was very likely also related to very high nematode populations.

Here is some info on Nematodes that may help you understand what they are and what they do to turf.

  Nematodes, also called roundworms or eelworms, are the second largest group of animals next to the insects with estimates of up to 500,000 species.  Most species are free-living occupying all ecological niches feeding on decaying animal and plant matter, algae, and bacteria,  some species prey on small soil-borne animals including other nematodes.

  Unfortunately, there are nematodes that parasitize animals and plants.  Roughly 3,500 species are obligate parasites of plants.  Most of these live in the soil and feed on plant roots, but rarely cause injury to grass cut above 1/2".     Plant Parasitic Nematodes range in length from 1/64th to 1/8th of an inch, are very thin and cannot be seen without a microscope. Nematodes are essentially a feeding machine that is much like a straw with a pump.  The front end has a piercing - sucking mouthpart called a stylet.  The strongly muscled stylet moves in and out of the body to feed.   It connects to a pump-like esophageal chamber which aids the nematode in the withdrawal of plant fluids.

 

So in quick terms, these worms harpoon the roots and suck the plant dry......not good.

 

 

 

 

 

We have again (August 7th) sent samples to Rutgers to see if any progress is being made.  Again, the reports show the greens are disease free, but loaded with nematodes...some of the numbers have declined slightly, but are still well above the thresholds.

We will continue to babysit the greens through the remainder of the summer and hope to see declining populations.  I want to thank Rutgers Director of Plant Pathology, Dr. Buckley, for his continued assistance and very impressive turn around times on our samples.


I appreciate all of our members who have taken the time to check in on my blog, while updates are infrequent, I hope the information is interesting and helpful.

See you on the course, JohnnyP