Can we talk FOLIAR NEMATODES please?

[ViolaAnn]

I don't see much discussion anywhere about foliar nematodes. But they have hit my garden big time and the number of plants with them increased dramatically last year even though I destroyed a few plants the previous year because they were showing signs.

As I understand it, they are a pest of the foliage and the soil and don't really inhabit the roots of the plants.

A Wikipedia article says,

Presently, there are very few control options for plants infested with foliar nematodes. The current recommendations are to destroy infected plant material, and avoid using overhead irrigation to prevent the spread of nematodes to new plants

.

Well, I'm not going to destroy or even try to cook 170 varieties of hostas. And even if I did, the plants would likely be reinfected from the soil when I replanted them. But, if I understand it correctly, plants that I did really early in the spring before they unfurl, should be free of nematodes. Then it might be possible to grow them in new soil in pots w/o an infection?

As for the garden, I'm cut down EVERYTHING this past autumn and cleaned it all up well. The overhead watering is more difficult to get around in a rainy season which the last several have been. (Maybe the nems have been there all along, but weren't noticeable until we had rainy summers.) I'm also going to douse everything with solutions of hydrogen peroxide which might help. Neem oil? Maybe it will help.

But I think we are likely going to have to learn to live with these beasts as a fact of life in our hosta gardens.

Your thoughts?

Ann

[Don Rawson]

There's an informative article by Bill Meyer in the current AHS Online Hosta Journal titled "Nematodes: Getting to Know the Enemy Better", which can be accessed by all AHS members.

Here are two other articles which may be helpful:

Infection Behavior and Overwintering Survival of Foliar Nematodes, Aphelenchoides fragariae, on Hosta
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2586432/

Astronauts of the Nematode World: An Aerial View of Foliar Nematode Biology, Epidemiology, and Host Range
http://www.apsnet.org/publications/apsn ... todes.aspx

[Phil_and_Gayle]

We've had a fair amount of success at controlling the beastly little things by treating with Imidacloprid (found in Merit or Bayer products). We sprinkle the granules around in the early spring before the leaves unfurl and the severity of the infection has decreased radically. We still have nematodes but they're not killing our plants anymore and the ugly leaves don't start appearing until late in the year.

I have also tried the heat treat method that works VERY well if you don't kill the plant in the process. I've saved four that way but killed two trying; a 66% success rate is nothing to write home about ;>(