Will glyphosate migrate to cherry from hack-and-squirt to beech?

[Peter Smallidge]

[a question from a woodlot owner that I'll keep anonymous]

I have some small diameter beech trees growing in close proximity to some healthy black cherry trees and I would like to take some of these beech out using the hack and squirt method described in your course. In some cases these beech are within inches of the black cherry at the base and appear to come out of the root-ball although I realize they do not. My concern is I do not want to harm the black cherry trees when applying the Round-up to these beech trees. Do I have anything to be concerned about? Round-up applied to the beech can’t “migrate” into the black cherry root system, correct?

I also have “patches” of beech stickers [approximitely 8-14 inches in height] I wish to control, should I apply the round-up to these as well?

[my response]

HI "woodlot owner":

 I don’t think you will have any trouble with migration of glyphosate into the cherry.  Glyphosate is the active ingredient in Round-up, and available in other products such as Accord XRT II, Rodeo, etc.  Most of my research has been with cut-stump, which uses significantly more glyphosate than hack-and-squirt (HAS).  In that research I monitored about 200 non-beech canopy trees (ash, cherry, sugar and red maple, basswood, etc.) that were within the treatment plots to assess the potential for migration.  Twelve months after treatment there were no indications of crown thinning or chlorosis in the non-beech; these would have been indications of migration.  HAS uses perhaps 10% (?) of the volume used in cut-stump, so even lower risk, though you can go much lower than 0.  I hate to make a promise, and I won’t, but I really can’t imagine how there would be any problem.  You can make this treatment any time through late October or early November.  You will want to use 25% to 50% active ingredient.  One hack every 3 inches of circumference.  Read the label and dilute as necessary.  I use a chemical resistant squirt bottle called “SprayMaster Chemical Spray Bottle.”  Other brands likely also work.  Search on the internet for the bottle…they are at Forestry Suppliers, Amazon, Ace and many other retailers.  Be careful using the hatchet.

I buy my glyphosate from Arborchem.com.  I have also purchased from Forestry Suppliers, Ben Meadows, and others.  They have Accord XRT II in 2.5 gallon containers and it is about 50% active ingredient.  This will treat a lot of beech.  Accord XRT II has a surfactant which will be useful in your situation.  You can also get glyphosate products at Tractor Supply and other local places.  Compare based on price per gallon for a given active ingredient; some formulations are more dilute than others.  There is also a convenience factor if you are driving by the store.

                                                                                                                                                            To make the dilution, remember that V1C1 = V2C2, where V is volume and C is concentration.  In your case, you solve for V1, the volume of the concentrate (C1) you are diluting. For example:

• V1 is unknown (you are solving for the quantity of the concentrate)
• C1 = 52% (the active ingredient in the concentrate as stated on the label, others might be 50%, 41%, etc.)
• V2 = 3 quarts (the total volume you think you will need)
• C2 = 30% (the concentration desired)
• V1 = (30) * (3) / (52) = 1.73 qts of concentrate and (3 - 1.73) = 1.27 quarts of water. 
• To double check, run the calculation assuming C1=50%, C2=25%, and V2=1 gallon. 

 

The smaller knee high whips you have can also be treated with a foliar spray.  Use about 1 to 2% active ingredient for the foliar treatment.  Note that the herbicide label may give dilutions for the % of solution, and that will roughly correspond to the percent of active ingredient.  Foliar is usually a low % mixture. When I spray foliar, if there are no nearby seedlings of concern and if the brush is dense, I’ll spray at about 4-5% active ingredient (the label maximum) because my time is more valuable than the chemical and I don’t want to have to re-apply.  A hotter mixture is helpful when the brush is really dense.  Your knee high sprouts may not be so dense, especially as you describe them as "patches."  Spraying the foliage will put nearby vegetation of similar or lower height at risk, so be alert to any plants that you don’t want treated.  Maple seedlings are fairly resistant to glyphosate, but don’t test them if you can avoid them.  Glyphosate works through foliage or exposed wood tissue.  Application to bark has no effect.

 I hope this helps.  This is a great question.  I’m going to post your question and my response on our Q&A forum at www.CornellForestConnect.ning.com .  I’ll encourage you to subscribe (it is free and easy) so you could post pictures of your project and also ask questions there.

 Let me know if you need more.

 

Peter