Dud Identification Collective Knowledge.

[Loc Dog]

Have found a bunch more articles, by googling - "stem nematode" hemp -

The use of quotes, and the word hemp, bring down the results from millions to about 5000.

Here is another good one -

http://www.plantwise.org/KnowledgeBank/Datasheet.aspx?dsid=19287

 

[RetroGrow]

Nematodes reduce the vigor of trees by attacking their root systems, making the tree more vulnerable to disease. Damaging diseases such as bacterial canker can be transmitted by nematodes. Weststeyn explains that the disease not only impacts the trees with nematode damage, but it is also highly contagious, posing a threat to previously healthy trees.

But the nematodes we are talking about are Ditylenchus dipsaci. They do not attack roots.

“I see Movento as being one solution we’ve got that provides a 50% reduction in nematode populations for five to six months after application.

Problem with that is, 50% reduction is not going to cut it. We need 100% reduction, and we can't wait 3 years for treatments to be effective.

 

[RetroGrow]

"The nematodes can be exterminated by soaking the plants in water containing 0.5% formalin @ a temperature of 24C, followed by a hot water treatment, with the addition of 0.5% formalin at a temperature of 49C (120F) for a period of 20 minutes."

The problem with this is that cannabis cannot survive 120F water temperatures. However, we learned in the fight against BMs that plants can tolerate air temperatures of 120F, so maybe someone who has these can do a test to see if 120F air temperature, after doing the 24C + formalin treatment, will kill them. We know that 120F for an hour does not harm cannabis, so it's worth a shot after the initial formalin treatment in 24C water (75C). Just maybe that will kill them. Test on a couple of plants only at first. You can easily get a temperature of 120F by parking car/vehicle in sun and putting a couple of plants in there. Monitor with thermometers, and crack windows a bit to reduce temps if it gets over 120. Problem is, we don't even know if plants can recover from these in a short growing season, or what other opportunistic pathogens may have attacked weakened plants, and may be adding further damage. We need lab testing to confirm whether other factors are at play here, and someone needs to try heat/formalin treatment. It may be that there is no way to "cure" this once the damage has been done. May just have to burn them and start over.

 

[xxxstr8edgexxx]

Excellent post retro. He's a thought. If there are pathogens at play it's likely easier to eliminate than the nematode. For genetics that are replaceable slash burn. But if not the treatment you describe could work especially if you took cuts in this atmosphere. Here's the reason I think this. If the temps are intolerable to them the most exposed and affected parts at the top will only have dead nematodes. The lower thick trunk and soil would be a cooler refuge. What if you waited til nematodes would be dead or retreated from the tops take cuts. Immediately cool and moisten them.

 

[Sam_Skunkman]

The more I think about this I have my doubts as gardens that freeze over winter still have nematodes in the soil in spring.
-SamS

 

[Sam_Skunkman]

Excellent post retro. He's a thought. If there are pathogens at play it's likely easier to eliminate than the nematode. For genetics that are replaceable slash burn. But if not the treatment you describe could work especially if you took cuts in this atmosphere. Here's the reason I think this. If the temps are intolerable to them the most exposed and affected parts at the top will only have dead nematodes. The lower thick trunk and soil would be a cooler refuge. What if you waited til nematodes would be dead or retreated from the tops take cuts. Immediately cool and moisten them.

What about eggs in the top you want to clone?
-SamS

 

[Sam_Skunkman]

But the nematodes we are talking about are Ditylenchus dipsaci. They do not attack roots.


I am pretty sure they can enter the plant through roots. They migrate to the stems.
-SamS

Problem with that is, 50% reduction is not going to cut it. We need 100% reduction, and we can't wait 3 years for treatments to be effective.

x

 

[Loc Dog]

Maybe try cold, Cannabis can stand very cold temps like 3-5C for long periods, weeks months under long light. I have zero idea if it would kill the nematodes in all life stages.
Try it and check after cold treatment. You will see if the adults and juveniles are dead, if not it is a waste of time.
The more I think about this I have my doubts as gardens that freeze over winter still have nematodes in the soil.
-SamS

Stem nematodes in the preimaginal state, have survived -80C for twenty minutes. They can lay eggs at 2C.

Look at the link, to the book, that I posted. Has loads of info.

 

[RetroGrow]

Stem nematodes in the preimaginal state, have survived -80C for twenty minutes. They can lay eggs at 2C.

Look at the link, to the book, that I posted. Has loads of info.

Right. The cold won't kill them. They survive over the winter, when they are completely frozen. When they thaw out, they are good to go. Those treatments on nut trees don't apply here, because the trees are treated for years. We don't have that luxury of time. I think the heat treatment has a chance, as we know 120F water dunks kill them in 20 minutes, so a longer time period in hot air after the initial formalin treatment might work. 120 F killed BMs without harm to plants, so 120 seems to be the magic number for someone to try.

 

[xxxstr8edgexxx]

What about eggs in the top you want to clone?
-SamS

yes. thats a good pont i need to read more on these from the posts linked by retro storm and loc. it would seem to me the eggs wouldnt be in the newest young itsy bitsy regions in the meristem that are very new. that said im curious if there would be reduced hatching at that temp or even elimination of viable eggs from the heat. ill read up. if it was a matter of growing them at 100+ temps for some days and then gradually raising o 120 to create nematode and egg free tops to grow clean apical meristem for t.c. i could see it working. just a thought.
obviously this should be tested im just thinking out loud for the sake of brainstorming.
there has to be a way to get enough clean material for a culture.

 

[RetroGrow]

yes. thats a good pont i need to read more on these from the posts linked by retro storm and loc. it would seem to me the eggs wouldnt be in the newest young itsy bitsy regions in the meristem that are very new. that said im curious if there would be reduced hatching at that temp or even elimination of viable eggs from the heat. ill read up. if it was a matter of growing them at 100+ temps for some days and then gradually raising o 120 to create nematode and egg free tops to grow clean apical meristem for t.c. i could see it working. just a thought.
obviously this should be tested im just thinking out loud for the sake of brainstorming.
there has to be a way to get enough clean material for a culture.

I'm guessing this treatment would kill eggs also, otherwise it wouldn't be much good.

 

[xxxstr8edgexxx]

@retro. what is the hottest hot water treatment you found them to tolerate?

 

[RetroGrow]

@retro. what is the hottest hot water treatment you found them to tolerate?

I believe the recommended hot water treatment for BMs was 113-115. This ruined my plants, so that's as far as I took it. No reason to go lower, as that wouldn't kill BMs. Ditched the water idea for cannabis, and went straight to hot air @ 120. Recommendation for nematodes is 75 degrees F with formalin, followed by second dip at 120, which we know won't work. But might work in hot air for second part of treatment. Only a test will tell.
Also, don't forget about hydrogen peroxide treatment I posted earlier. That's another possibility.

 

[redlaser]

UC Davis IPM calls for hot water treatment to be 110.3 degrees for thirty minutes. www.ipm.ucdavis.edu/PMG/r280400211.html another possibly more practical method is 100 percent humidity at 110.3 degrees for larger plants. In my limited experience doing this it seems the water would only be practical for smaller plants, like cuttings, because the plant floats and temps are higher on the bottom of the water container. It's interesting as a possibility against nematodes though as well, at 111 degrees for thirty minutes. For larger plants and broad mites 120 air makes more sense. It should be noted I have yet to successfully try the 110 degree water dip, but t seems like a no-brainer to at least give it a shot

 

[Storm Shadow]

http://www.agriculturejournals.cz/publicFiles/08130.pdf

Effect of Plant Essential Oils on Mortality​

of the Stem Nematode (Ditylenchus dipsaci)

The aim of this study was to assess the nematicidal activity of different essential oils from medicinal and aromatic plants for use in nematode management. Essential oils of​

​

​

​

Eugenia caryophyllata, Origanum compactum, Origanum vulgare, Thymus matschiana and Thymus vulgaris showed nematicidal activity against Ditylenchus dipsaci
​

 

[RetroGrow]

http://www.agriculturejournals.cz/publicFiles/08130.pdf

Effect of Plant Essential Oils on Mortality​

of the Stem Nematode (Ditylenchus dipsaci)

The aim of this study was to assess the nematicidal activity of different essential oils from medicinal and aromatic plants for use in nematode management. Essential oils of​

​

​

​

Eugenia caryophyllata, Origanum compactum, Origanum vulgare, Thymus matschiana and Thymus vulgaris showed nematicidal activity against Ditylenchus dipsaci
​

Mortality is too low. They will reproduce faster than they die.

 

[Loc Dog]

http://www.agriculturejournals.cz/publicFiles/08130.pdf

Effect of Plant Essential Oils on Mortality​

of the Stem Nematode (Ditylenchus dipsaci)

The aim of this study was to assess the nematicidal activity of different essential oils from medicinal and aromatic plants for use in nematode management. Essential oils of​

Eugenia caryophyllata, Origanum compactum, Origanum vulgare, Thymus matschiana and Thymus vulgaris showed nematicidal activity against Ditylenchus dipsaci
​

Do not know of the efficacy of treatment, but that would be clove, wild oregano, oregano, majorum and thyme oils.

 

[Storm Shadow]

"The essential oil of ​

​

​

​

Origanum vulgaregreatly suppressed the D.dipsaci population in comparison to the untreated control"​

​

​

"soil treatment with essential oils could have a potential for soil disinfestation as an alternative to chemicals. However, while it is clear that several plants contain compounds which can be used to protect crops against plant parasitic nematodes (Grainge & Ahmed 1988; Chitwood 2002), the mechanisms involved in the nematicidal activity are known only for few groups of plants."​

In conclusion, our results have demonstrated the nematicidal properties of essential oils of Eugenia caryophyllata, Origanum compactum, O. vulgare, Thymus matschiana and T. vulgaris against Ditylenchus dipsaci

 

[Hammerhead]

Great work SS. All you guys have done a fantastic job on this.. I hope this puts an end to this problem. Has anyone treated a dud with success yet??

 

[RetroGrow]

Just to clear something up, from my reading: Ditylenchus dipsaci do not enter through the roots, but rather the stomata. So they come in through the leaves, not roots. It's the only species of nematode that works in this fashion. Very strange to say the least. Counter intuitive. This may mean that foliar sprays may work better than drenching.
Here is link posted earlier. Someone may want to try a test with this chemical using foliar. Note: it should not be mixed with other pesticides.
http://www.ces.uoguelph.ca/water/PATHOGEN/PeroxyaceticAcid.pdf
Someone may want to do a similar test with formalin, but don't go over 1%.