Nematodes..Guess I'll start it this year

[Carol W]

Mary Ann you may be right, but how does foliar nematodes enter into a plant is it from the soil or leaf or both? My thought of thinking if planting marigold would help control infection of nematodes until a new appoved treatment is released on the market. Also in the link posted below it tell of using the crushed shells of crustaceans. When reading the below link and others what amazed me was certain weed seeds could start the nematodes.

http://attra.ncat.org/attra-pub/nematode.html
"Preventing nematodes from entering uninfested areas is important; under their own steam they can spread across a field at a rate of three feet per year. The following measures will help prevent human-assisted spread of nematodes to uninfested fields:

Use certified planting material
Use soilless growing media in greenhouses
Clean soil from equipment before moving between fields (washing equipment—including tires—with water is most effective)
Keep excess irrigation water in a holding pond so that any nematodes present can settle out, pump water from near the surface of the pond; plan irrigation to minimize excess water
Prevent or reduce animal movement from infested to uninfested fields
Compost manure to kill any nematodes that might be present, before applying it to fields (Kodira and Westerdahl, 1995)
Eliminate important weed hosts such as crabgrass, ragweed, and cocklebur (Yepsen, 1984) "

Using crustaneans:
"Most nematode species can be significantly reduced by tilling in chitinous materials such as crushed shells of crustaceans (shrimp, crab, etc.). This is effective because several species of fungi that "feed" on chitin also attack chitin-containing nematode eggs and nematodes. Increasing the amount of chitin in the soil will also increase the population of these fungi. A shrimp-shell-based fertilizer called Eco Poly 21™ Micro shrimp fertilizer is available from Peaceful Valley Farm Supply. At 2002 catalog prices, it would cost between $87 and $216 to treat an acre with this product (the suggested application rate is 20 to 50 lbs. per acre). Clandosan™, a nematicide made of crab shells and agricultural-grade urea, can be used as a pre-plant treatment (it should not be used on plants because the amount of urea in it can "burn" or kill them). (Fiola and Lalancettle, 2000)"

[Quiet Storm]

Well,
Discovered nems in my newest hosta bed this morning -- on Donohue Piecrust. I had already treated it with Disulfuton last week, so I just removed the affected leaves this morning. Sprayed it with homemade insecticidal soap on Saturday. I thought it might have them on Saturday when I was spraying, but wasn't sure until this morning. I think the culprit in this particular section of the garden is a thick stand of Lily of the Valley in an adjacent bed, and there is just too much of it to get rid of. I gave it a good soaking with the insecticidal soap, and will continue to do so weekly for the rest of the summer. Lots of heavy rain and thunderstorm activity here in eastern MA over the last several days, and high humidity.

Hostanquilts, the disulfoton product I have been using is Bonide Systemic Insecticide Granules - 2% Di-Syston, which I bought a local nursery last year, but when I do an online search now, it does not seem to be readily available (which is not good, because I am running out). If I remember correctly, it took me awhile last summer to locate a nursery that had it in stock. I believe Bayer has systemic rose and flower care product (in granular form) that has 1% disulfoton. Hope this is helpful.

[playinmud]

Interesting reading Carol. I tried the marigold treatment on a hosta bed, but it had no effect. I had used them years ago with the root knot nems, and it worked like a charm, but doesn't seem to do anything for the foliar nems.

[Quiet Storm]

Discovered more nems over the weekend, in two separate plantings of golden scepter. I destroyed all but one of the 10+ plants, and treated the planting holes with boiling water. The one I kept has no sign of nems at present. I potted it and put it in a full sun location, away from other hostas.Time will tell. The golden tiara I heat treated last year has so far shown no sign of nems this season, and it is usually among the first to show symptoms. Francis Williams showed more signs of nem infestation, so I dug and potted it and treated it with disulfuton. If it survives, it survives. The Inniswood I heat treated a few weeks ago is putting out new leaves, but only on one of the three sections into which I separated the plant. The other two divisions aren't showing any growth yet. I've continued the weekly application of homemade insecticidal soap, and so far the majority of my hostas have shown no sign of nems.

[DBoweMD]

Time to report in on my Nematode treatment results...
I had about 40 plants isolated in the side yard area that I treated with Bonide brand Disulfoton granules last fall, they looked good when I checked in Late June, but not as good in mid July to August. I separated the good from the infected looking ones. The ones showing signs of Nematodes I have re-treated and left in the isolation area. This year I removed any leaves that appear infected because I know that the granules don't work on the nems that are in the leaves. The good looking ones I have brought out and will plant them all together in a low area of the yard. I would say that about 2/3 look good, about 20% had minimal damage, 10% had fair damage and 5% had a lot of damage. All were in pots on the ground for the winter. 1 plant did not come up at all (Doubloons) and one looks to have just gotten crown rot this week (Lemon Meringue) with all the leaves pulling out with slimy bases.

I think I'll probably use the Disulfoton on small plants, but on larger ones when I only have one specimen I'll divide them and at least try the heat treatment on part, because I have had 100% eradication with that, but some death too.

[eastwood2007]

This year I removed any leaves that appear infected because I know that the granules don't work on the nems that are in the leaves.

Hi, Dave -

Could you explain what you mean by the granules don't work on the nems that are in the leaves? Could you tell us what you know about how the disulfoton works? It would be very helpful...

[DBoweMD]

Charla,
Last season I kept the nem infested plants in my driveway in pots where there is some sun, between where the 2 cars go, treated them in July with the disyston granules. I did not remove any leaves. I checked the leaves every few weeks after that under the microscope at work.
Every single time I examined a suspected leaf, I found them alive and thriving. I did it until October, and thought it was a failure, so just put them all together in the quarantine area for the winter, hoping that it might work over the winter. I was thinking about dividing the bigger ones to heat treat a piece.
Well, apparently the stuff can stop them from going back down into the crown to overwinter, or lay eggs, or something. I treated a heavily infested Maui Buttercups in a pot with disyston two years ago and it has been great for the past two seasons.

[thehostagourmet]

Dr. Dave, did you put the 'Maui Buttercups' leaves under the microscope, or were they just visible symptoms? How many yearly treatments are you giving the infected plants?

[Chris_W]

I wonder if Merit insecticide will provide any kind of symptom suppression? It is listed as a tree and shrub systemic with 12 month control. Wonder what it would do to nematodes?

[DBoweMD]

George, the Maui Buttercups was by visual inspection 2 years ago. I had not figured out how to get hold of a microscope at that time.
It was just one application, about a tablespoon in a gallon pot.

[JoshS]

I wonder if Merit insecticide will provide any kind of symptom suppression?

Depends on what you read...

http://www.esn-symposium.ba.cnr.it/post ... df/209.pdf

http://www.hdcchem.com/Imidacloprid.html

http://www.stlouishosta.org/newsletters/11-05.pdf

It works on animal nematodes...

http://www.advocate-spot-on.com

[Chris_W]

Thanks for the links Josh. Again, it seems we have to make a distinction between soil nematodes and plant parasitic nematodes. One article says no effect on nematodes, which is very generalized. Another states no effect on soil nematodes. The difference might be on what the nematodes are feeding on. If they are feeding on a plant part that contains an insecticide that might do the trick, but if they are feeding on something else then there might not be any worthwhile results.

[JoshS]

I agree, Chris. I couldn't find any reference to foliar nematodes. It certainly would be worth a try!

During the "Grower's Perspective" panel discussion at the National Convention, Bob Solberg said the adult nematodes are fairly easy to kill. It's the eggs that are the problem.

[Pieter]

A further update with respect to my bleach bath experiment from last year.

8 varieties were trimmed of all their leaves and given a bath for a couple of hours in an 8% bleach solution. Some were divided into single eye crowns and not all of those came back up this spring, and while I may have lost a couple, I still have all 8 varieties growing. Some with more vigour than others perhaps, but overall I'm satisfied with their recovery. 7 of the 8 are not showing any signs of a return of the dreaded worms, but one of them, Ice Age Trail has a couple of leaves that show signs of concern. I'll have to go digging around to find a loupe/magnifier before I put the leaves in water and will report with my findings once I have done so.

The two varieties which showed the worst infestation, Fire Island and Tattoo, were two of the three I divided and because the crowns and roots were quite small there will have been deeper and more complete penetration into the tissue to kill off the nematodes. Both have come back up with decent growth and both, thus far, would seem to be totally clear. The IAT crown and roots were by far the biggest of all and the duration of the bath may not have achieved the needed penetration as a result. Since I do like IAT and now have 2 eyes on the crown I will probably divide it and re-bath it for a longer time period, if indeed the water testing of the leaves shows the presence of nematodes.

I'll go as far as saying that likely one of the reasons for my seeming success with this procedure is the fact I divided them into a smaller mass where practical to do so, to aid in the depth of penetration. All treated Hostas were potted and have all been sitting in a tray with water for the growing season to serve their water needs and not have to worry about splashing water off leaves when watering with a sprayer of some sort. In spite of what I'm going through with IAT at the moment, based on what I have seen so far this season I'm prepared to give the bleach bath a provisional 'thumbs up'. This is only year one however and who knows, I may be crying the blues again over this issue next year. Stay tuned!

[Quiet Storm]

I reported a few weeks ago that I had dug, heat treated, and potted a nem infested Inniswood. Also treated it with disulfuton after potting. Well, one of the three divisions has put up a flush of new leaves, very small, but looking healthy. Don't know if I killed the other two divisions. I've got them in full sun for now, and will closely monitor their progress. The Golden Tiara I heat treated last year is still looking great. I potted it after the heat treatment, then planted it back in its original location at the end of the summer (I had drenched the planting hole with boiling water after digging the plant). Inniswood is the only plant in that area that came up with nems this year. I'm still using my homemade insecticidal soap spray weekly, but have no idea whether or not it is helping, since I have also treated the plants with disulfuton. Question, if the nems are inside the leaves and crown, how would insecticidal soap, which is a contact insecticide, help control them?

On another note, I have noticed that some varieties seem more susceptible than others to nem infestation. Golden Scepter seems particularly so. This is the second year I've had to get rid of multiple Golden Scepter plants. Have others found that certain hostas seem more susceptible?

[DBoweMD]

I think plants with thinner substance will show the signs earlier than the thicker leaves. Golden Scepter vs Ice Age Trail is a good example.

[poppi]

I have tried the hot water treatment and boy it really set my hosta back. I won't do that again. I've also tried putting the hosta in a hot car all day. That seems to have helped as well. A few years ago I saw an article about Pylon effectiveness on nematodes. I bought a bottle. It wasn't cheap but I think if will last a lifetime. Anyway, I'm really impressed with how well it works. Although I haven't completely gotten rid of them, they are so much better. I can't believe it! I also heard that Bayer shrub and tree spray also works.

Good luck!

[Chris_W]

I've had great results with the hot water treatment - but yes, I've lost a few hostas this way too. If it is expendable I just throw them away. The hot water treatment is really the only thing that has been proven 100% effective for curing nematodes in the plants. The hard part is that nematodes can survive in the soil and it is close to impossible to get rid of those.

I tried Pylon in 2005 on some Darmera (umbrella plant) that were horribly infected. In 2006 saw no signs, then last year only a little, again this year only a little - and I only did the one treatment in 2005. So it managed to drop the levels considerably, and mother nature (heat/drought) is probably controlling them some too.

Poppi, the active ingredient in the Bayer Tree and Shrub spray is Merit, the insecticide mentioned previously. It is still a little expensive but nothing like the Pylon. I think I paid $300+ for a pint of that

[playinmud]

I had posted a thread in another forum last year containing a recipe for a homemade insecticidal soap soultion that I'd concoted using Dr. Bronner's liquid soap, a generic mint flavored antiseptic mouthwash and powdered garlic in water. I'd add it to a pump sprayer and douse my hostas once a week through mid-September. I didn't want to spend a lot of money, dig anything up, cut anything apart, use anything that would be toxic to me or set my plants back by heat treating, so I came up with this. I also mid season added a few tablespoons of tobacco juice in a few of the applications (I don't live near any water, so wasn't concerned about hurting aquatic creatures). This season I haven't had time to treat anything, so what I'm seeing is a result of last year's efforts. I have one bed with nems, only 5 hostas are showing signs of nematodes this season. That is amazing to me, because two years ago everything in this bed was infected, last season there were about 12, and this season only 5. No, its not 100%, but the results are more positive than not. I need to douse them now through the end of the season, and see what the results are next year. I also follow Bruce's mother's bleach soak for all new hostas, That should keep any unwanted creatures at bay.

[baja220]

I also follow Bruce's mother's bleach soak for all new hostas, That should keep any unwanted creatures at bay.

Donna, what's this bleach soak?