Nematodes

Tigger · Post by **Tigger** » Jun 29, 2007 10:02 am

Chris, I'm going to post your excellent nematode treatment advice to the hosta FAQ, if you don't mind. That way it will have a permanent home. The info that's already there (with a pic) is not as helpful as this.

eastwood2007 · Post by **eastwood2007** » Jun 29, 2007 4:35 pm

Here's a pic of the hosta I got from Rob Mortko. See the brown between the veins. It also came on suddenly...like it wasn't there Wed. but was there yesterday. I was also going to take a pic of a leaf on Dalton's Pick I just got this year, but the leaf already totally died. It had had some insect damage then the leaf turned translucent....again all transpiring nearly overnight. That's why I am wondering if it is the rain. The ones I am talking about are all in pots and I had been watering when we didn't get rain since pots dry out so fast, but not watering lately with all the rain.

See the brown strip at about 3 o'clock? Then the translucent strip at about noon? I dunno...please tell me what you think.

ademink · Post by **ademink** » Jun 29, 2007 4:54 pm

Sure looks like it to me.

Jamie · Post by **Jamie** » Jun 29, 2007 5:20 pm

Those looks like Nematodes to me also

Unfortunately it's inevitable that this comes to the garden. I've been really paranoid and keep potted plants isolated that I get from a nursery on the west coast. This nursery is a highly reputable nursery also

. Thank god I seen it before grounding the plants in the bed here and I just threw them away.

hubble · Post by **hubble** » Jun 29, 2007 9:06 pm

Charla, I think it has to do with the Easter freeze. I'm in Overland Park and I know you've gotten a heck of a lot more rain than we have...but I still blame the freeze (and a nasty outbreak of slugs).

I've never had to use slug protection till this year. I guess the previous years of drought was a benefit in that area.

I have Blue Cadet that has been in the ground for years. It was so crowded, I divided it before the freeze. I put the division in a pot and planted later. The division does not have any symptoms of nematodes. Yet, the Mother plant looks horrible.

Tell me what you think.

ademink · Post by **ademink** » Jun 30, 2007 1:03 am

Hmmm....looks like 'todes to me. But maybe I'm getting insect eyes at this point. LOL

Post by **Chris_W** » Jul 01, 2007 1:56 am

Hi Tigger,

Yes, feel free to copy the information about heat treating.

And Charla and Hubble, those do look like nematode problems, especially the Blue Cadet.

A few more things - I think that if you have a plant that is cheap enough, it is usually a good idea to just throw it away, especially if you haven't had it long.

Next, the heat treatment is reported to kill nematode eggs and adults, but I'm not sure how much research has really been done to prove it. It only takes a few eggs or adults to survive and you have them again eventually. Bob Solberg mentioned that temps over 110 are actually enough to kill the nematodes and suggested that if you close up a greenhouse and get it that hot it will heat treat large numbers of potted plants. Might do a lot of damage, too, though, but that comes with the heat treatment sometimes. Putting plants out in the sun could sure help too. On a driveway or against a really hot building it might work to heat treat the plant in the sun and over time could really reduce the number of nematodes.

Heat treating soil has long been recommended for getting rid of soil nematodes, using black plastic to cover and cook your bare earth. In the shade that is harder to do, so that's why the boiling water method was suggested.

When you are handling all of these plants, be sure to wash out the buckets, wash off your tools, and wash your hands before going out in the garden and touching anything else. Some even say you should try to limit walking through where there might be nematodes. Supposedly you can move them around the garden on your shoes.

In climates where the temps are regularly above 100 degrees they almost never see nematode damage. Same in areas with very little rainfall, although we often water plants enough to help in that regard.

Chemical treatments: The peroxide treatment, diazanon, and other insectides have been reported to reduce the number of adult nematodes present. But unfortunately these chemicals don't do anything about the eggs, so even if you kill the adults the eggs will just hatch and a whole new cycle will start. So although chemicals will help to reduce the nematode population they will never really "cure" the plant. Some people even worry that the chemicals will just mask the problem and then you won't even know they are there.

I hope that helps to answer some of the questions. The main concern with any nematode treatment (hot water, sun, chemical) is that these microscopic worms are so prolific you may never really get rid of them 100%, but the heat treatment seems to work the best from what I've seen and heard.

eastwood2007 · Post by **eastwood2007** » Jul 01, 2007 7:53 am

Chris, thanks so much for getting in this discussion. I have been so fortunate so far not to have gotten HVX or nematodes, and this just makes me sick.

Is there a list of plants that are susceptible to nematodes? Or ones that aren't? I have plants on the floor in my greenhouse...my jasmine actually came in contact with the suspected nem carrier. I can move them out and heat and bleach treat the greehouse, but I wonder about Caladiums, Impatiens, and others. Also, I have a wood plank floor in part of the greenhouse where the hosta was sitting. Can it be completely treated?

Also, is there any chance it is the wet weather? Here south of KC we haven't even hit 90 degrees, yet?

Post by **Chris_W** » Jul 01, 2007 9:00 am

Hi Charla,

Can you close up the greenhouse for a little while so that the temperature builds? If it gets up near 110 it should kill most if not all of the nematodes. You could also use extra hot, soapy water to wash the area, but to be honest I wouldn't worry too much since you didn't have the hosta that long there, and your Sun Power didn't look like it had too many. The insecticide in systemic rose care is reported to kill nematodes pretty good (adults) too, so you might consider sprinkling a little bit of that in the pots.

I've seen this sort of streaking in between the veins before during cool, really wet weather. It came out a couple years ago in the spring and really looked like nematode damage, but was way too early. This is really the time of year to be seeing it, so it wouldn't surprise me that much.

As for hostas, no there aren't some that are more susceptible than others, some just show the damage worse. As for other plants I'm not sure, but I've read that grasses don't get foliar nematodes.

I hope that helps.

Chris

ademink · Post by **ademink** » Jul 01, 2007 5:06 pm

Hey Chris...what if you have what looks like nematode damage but then when you do the water test...no swimmers? (insert head scratching icon here...I can't find it

)

Does that mean that it isn't nematodes or just that there aren't enough to be present in the water or...?

ademink · Post by **ademink** » Jul 02, 2007 9:20 am

Bump.

ademink · Post by **ademink** » Jul 03, 2007 12:07 am

Waving my arms hoping Chris sees this. lol

Post by **Chris_W** » Jul 03, 2007 12:24 am

I've heard the same from other people, that sometimes you can't see them, but then others have said that means you don't have a powerful enough microscope. Basically, I don't know, but if you see the distinctive symptoms in July/August/September it's most often them.

ademink · Post by **ademink** » Jul 03, 2007 12:28 am

Thanks again! Anything that looks remotely suscpicious is being dug up and potted in the leper colony. *sigh*

It appears that several I received in trades last year are infected. Honestly, I can live without those particular ones. What troubles me are the NEW ones I received two months ago that definitely are showing signs.

I'm freaked out b/c two of them were in my favorite hosta bed - the very front of it. They were touching my Tok. Aureonebulosa (incredible this year) and a VERY mature and huge Halcyon.

I have no signs of nematodes on those two hostas but fear that it is only a matter of time.

I feel like I have ticking time bombs in my beds!

Drama rising, roflol
andrea

VThosta/daylilylover · Post by **VThosta/daylilylover** » Jul 03, 2007 3:21 pm

Here is a photo of the underside of a leaf from my fortunei aureomarginata. I need to know how to do the test to see if there are nematode worms in it. Let me know what you think. Thanks!

HostaDesigner · Post by **HostaDesigner** » Jul 03, 2007 3:46 pm

VThosta/daylilylover wrote:Here is a photo of the underside of a leaf from my fortunei aureomarginata. I need to know how to do the test to see if there are nematode worms in it. Let me know what you think. Thanks!

Honestly, that does not look like nems to me. Nems follow the veins tightly, this one doesn't. See how the brown cuts into the center of the vein and doesn't hug the edges? That the part that's making me a skeptic. You can do the water test to be sure, but this looks like something else.

My NBC seedling showed very similar traits last year and it's fine and dandy with no infection.

HostaDesigner · Post by **HostaDesigner** » Jul 03, 2007 3:50 pm

Oh yeah, to do the water test, submerge a leaf (or part of a leaf) in a clear glass jar of water for several hours. Then take the highest powered magnifying lens you can find and look at the jar while holding it up to light. You'll be able to see tiny, tiny silky hairs swimming in the water if it's nematodes.

VThosta/daylilylover · Post by **VThosta/daylilylover** » Jul 03, 2007 4:25 pm

Thank you! The leaf is swimming as we speak... looking at the pic again, those brown streaks are symmetrical along the stem. There are similar marks on the undersides of other leaves on this same plant but they aren't symmetrical (yet?).

eastwood2007 · Post by **eastwood2007** » Jul 03, 2007 11:36 pm

Well, it was confirmed today by tests done at the extension office that the hosta I returned to the local garden center came back positive for nematodes. This is not the one I got from Rob Mortko...I wanted to be sure that was mentioned. I hope I caught it in soon enough that I can accomplish damage control.

I have one other that looks suspicious so I am going to try the water test on it. When you describe the worms as silky, squirmy threads...are they longer and thread like? Or are they shorter and chunky like? Are they white, silver, greenish? Do they visibly move in the water? I am trying to get a better idea of what I am looking for. Does anyone have a magnified pic of them in the water?

Thanks for everyone's help! You all are awesome!

eastwood2007 · Post by **eastwood2007** » Jul 03, 2007 11:41 pm

Oooops! Forgot a question...in regards to nematodes...if I have a hosta that is infected, will it definitely show symptoms by the end of the season?

Hallson Gardens

Nematodes

Is this it?

Re: Is this it?

Thanks!