Controlling Buckthorn

[wysiwyg]

I've been using Roundup (the 18% glyphosate variety diluted per label instructions) to control sprouting buckthorn stumps and immature trees with pretty good success. The problem is that it takes 4 or 5 applications to get a complete kill.

Would any of the higher concentrates of glyphosate provide more immediate results? Would triclopyr (ie Brush B Gone) work better? I've also seen "Garlon 4" mentioned as a treatment, but don't know of any brands that use it...any ideas?

Thanks.

 

[M.D. Vaden]

If these are not sprouts from stumps, but "young-bucks", it would seem profitable to shoot for one application, or less anyhow.

On sprouts of about anything, I use label rate or 75% also.

If the leaves are washed off, that's better. Dust is not good.

Try a surfactant to spread the droplets out.

If you're frugal, maybe a few drops of dish soap.

Do you spray the underside of the leaves too? That could be limited a bit by what else is around.

Try a lawn weed killer too sometime. Usually, what kills lawn weeds, kills trees too.

 

[Stumper]

Based on my own experience I think that you will have better results using Triclopyr. It is especially effective used full strength on freshly cut stumps-an application which isn't label recommended for Round-up.(My understanding is that round-up requires dilution for absorption -even on fresh cuts)

 

[Tom Dunlap]

YOur final dilution rate is what's important. If you're starting w/diluted RU you are probably thinning it too much. That's why you have to go back several times.

Tom

 

[M.D. Vaden]

Final dilution may not be the problem.

For me, when I went from 100% recommended dilution of RoundUp, to 70%, the kill factor dramatically improved.

The slower the kill the better.

Full strength with many herbicides is a faster kill of top growth and upper root.

Dilluted rates let the plant translocate the herbicide deeper and more completely before final kill.

There probably are better herbicides than RoundUp, but if someone does not need to pay out for an extra bottle on the shelf, the dilution method is worth the experiment - but it requires clean leaves, spraying the underside of leaves, and a surfactant.

 

[wysiwyg]

Thanks for all the replies!

When I spray, I normally spray from all angles, but don't specifically try to get the underside of the leaves wet - although I'm sure a lot of them do get covered. I'll pay more attention to this from now on.

I did a little more research on tricolpyr and found that it does have a residual effect, up to a year, on the soil. This is something I'd like to avoid, so I think I'll stick with roundup.

To state my original question better, what I really would like to know is, is there a consensus on what post-diluted concentration of glyphosate provides optimum results for foliar treatment of buckthorn? The roundup concentrate comes in so many different concentrations now, it gets confusing.

Also, how much of a surfactant (dish soap) is recommended for a gallon of prepared solution?

I've also thought about adding dye to keep track of where I've sprayed, does food coloring work?

Thanks!

 

[Kneejerk Bombas]

We use a different chemical for stumps, so I can't answer your roundup question, but I have some experience with food coloring, it works, sort of. Even with a bottle or two in a tank, it just barely stains the wood, it's not bright red or anything, but if you look closely you can tell it's been sprayed.

 

[John Paul Sanborn]

Food coloring, organic dyes, water color paints all good for markers.

Add a hort oil to the mix, or a sticker.

Best is to time the application for fall when the trees are storing more in the roots, more product is transloacted with a more efficient root kill.

I think that the dilution rate is a problem since you are starting with a 18% active product. Many of the research papers I've read recomend 20-25% dilution rates for stump and frill painting. I've read papers put out by WI and MN DNR and UniExt outreach.

I've doen the stump paint with a 20% active dilution in hort oil and waterwith an 80-90% kill rate on the first app. So as with all control methods, dose and timing are essential.

I have read that with honeysuckle control a garlon spike is more effective. Cannot find the papers on the internet at this time.

Try searching "invasive plant control".

 

[Tom Dunlap]

There are agricultural dyes available. I've heard that Rit fabric dye works too.

I'll bet that the WI DNR has plenty of info for you. Call your regional office.

Spend some time with Google too.

http://www.dnr.state.mn.us/fish_and_wildlife/exotics/buck.html


Tom

 

[M.D. Vaden]

The dilution of the bottle should not be difficult.

Basically, whether the active ingredient is 18%, 41% or, is it also near 50% now - the bottles all give a basic mixing rate that leaves you with the same result in your pesticide sprayer in the end.

First, RoundUp was the near 41%. That's at 2 oz. per gallon.

Then the 18% is about 4 oz. per gallon.

Just follow the general use mixing rate and you will be the same in the end in the tank.

I liked Sanborn's input about fall. That is a premium time to go for many small trees.

Holly is different, because in spring, the leaves don't have the waxy cutin developed yet.

This pesticide stuff almost gets away from me now. In 1988, I was a licensed pesticide consultant with the State of Oregon. Then I got tired of applying. So I dropped all my licenses and only apply a very small handfull of goodies.

I think I'll take the Pesticides class at the college again for a refresher in a couple of years and see what's new and abused in the industry.

What bugged me about using chemicals - the experts can tell you how one pesticide can affect you with minor residue, but they did not have information about minor contact with several different chemicals in a week. That's what got me to back down in that field.

 

[John Paul Sanborn]

Originally posted by M.D. Vaden
The dilution of the bottle should not be difficult.

Basically, whether the active ingredient is 18%, 41% or, is it also near 50% now - the bottles all give a basic mixing rate that leaves you with the same result in your pesticide sprayer in the end.

You are missing my point, there are studies that show 20-25% dilution will render a near 90% control rate. If you sstart with 18% you're not going to do well. I too have given up For Hire spray work (I did not like it when my lymph nodes swelled up every time I sprayed Sevin ) so i have not read the lable lately. I'm big on pointing out that the lable is the law, but if you have the documentation on a 25% active dilution this would fall under special use rules.