One gardeners protocol for controlling foliar nematodes in a hosta collection.

Most hosta collectors are aware of the problems foliar nematodes can cause in a hosta patch. I'd like to share with you my method for controlling foliar nematodes in my hosta collection of 650 cultivars consisting of 3000 plus individual crowns.
 
For starters I strongly believe in physical isolation of foliar nematode infested hosta crowns. Each and every hosta that I find with nematodes I remove from my main hosta garden and isolate them in a separate garden I call my nematode bed. This hosta bed is separated by 400 feet from my mail hosta patch. I always leave the hoe I use for weed control in this hosta bed and I'm very careful never to work in my nematode bed and then work in my main hosta garden.
 
When I find a foliar nematode infested hosta here's what I do.
 
1) I Immediately dig and move the hosta with as much soil as I can to my nematode bed.
 
2) I check very closely all neighboring hostas and remove the leaves that were closest to the infected plant. The leaves I remove from these neighboring hostas show no sign of nematode damage. If they do show nematode damage of course they too get moved to the nematode bed.
 
3) I place a 4 foot yellow fiberglass rake handle in the ground where the infected hosta was growing. I then spray a 10 foot diameter circle centered on this yellow marker with Oxmyl or Nemacur 3 doing a good foliar application and soil drench at the same time.
 
4) I check the hostas near this marked area regularly for any further signs of foliar nematodes.
 
If I have the same hosta in another area of the garden that came from a different source I throw away the infected hosta unless it is one with a high value. If I have several crowns of the same cultivar that are infected I throw away all but one of these hostas and move the infected hosta to the nematode bed. I believe that inexpensive hostas that have foliar nematodes should be thrown away. By thrown away I mean placed in a garbage bag to be collected by a trash hauler.
 
Here's the protocol I use on my nematode bed.
 
1) June 1st I foliar spray and soil drench my whole nematode bed with Oxmyl or Nemacur 3. I use 40 gallons of mix on a bed that's approx 1,000 square feet in size. I also spray a 10 food diameter circle marked by my yellow rake handles in my main garden.
 
2) June 15 (two weeks later) I repeat this application.
 
3) June 30 (two weeks later) I repeat this application for the third time.
 
4) July 15 (two weeks later) I repeat this application for the fourth time.
 
4) July 30 (two weeks later) I repeat this application for the fifth time.
 
My goal is to kill the foliar nematode in it's adult stage. My reason for repeated applications is to give all nematode eggs a chance to hatch and catch them in their adult stage with a spray application. My hope is that after 5 applications almost all nematode eggs and or nematodes in their dormant stage would hatch or become active and vulnerable to the spray application. I time the first spraying June 1st figuring that environmental conditions are right for all eggs to hatch (warm weather) and for all dormant stages to become active (warm weather). It is my understanding that eggs and dormant stage nematodes may not be killed by spray applications.
 
I came up with this protocol myself based on what I have heard and read on the life cycle of the foliar nematodes that affects hostas. I'm using restricted use chemicals that are not available to most home gardeners and they are not available for a good reason. These chemicals are dangerous and need to be handled and applied using the correct personal protection equipment and application methods.
 
Dr. Grewal has found less toxic or non-toxic chemicals or controls for foliar nematodes in hostas and I suggest a protocol similar to mine for their application. I of course would gladly change my methods for nematode control and am anxious for Dr. Grewal's input.
 
Dan Nelson
 
P.S. My nematode bed was not treated in 2001 and no signs of foliar nematode activity was noticed. I realize of course that I may still have small numbers of foliar nematodes that are not at a high enough population level to show physical damage to the hosta leaves. 
 
 
 
 
 
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