Crop & Pest Report

Accessibility


| Share

Sprayer Calibration for Spot Spraying (06/08/17)

Question: I have been fighting a losing battle with leafy spurge for 49 years, starting with hiking up every drainage outlet with a backpack, using Tordon pellets, collecting hundreds of thousands of beetles, and grazing 1000 sheep several times a year, but the problem is worse than ever.

Sprayer Calibration for Spot Spraying

Question: I have been fighting a losing battle with leafy spurge for 49 years, starting with hiking up every drainage outlet with a backpack, using Tordon pellets, collecting hundreds of thousands of beetles, and grazing 1000 sheep several times a year, but the problem is worse than ever. I am trying a mix of Plateau + Tordon + 2,4-D amine in a 100 gallon diaphragm sprayer this year for spot spraying. The recommended rate of Plateau is fairly expensive. I haven't calibrated my sprayer, but I certainly do not cover even close to an acre with 100 gallons. You list a rate of Plateau at 4 fl oz/A + Tordon at 1 pt/A + 2,4-D at 1 qt/A + MSO at 1 qt/A. By combining chemicals would a spot treatment rate in that range of Plateau at 8 fl oz/A be sufficient for spot treatment in my meadows? I hate to use too high of a rate as I have spreading stands of creeping foxtail, but I do not want to wait until fall either.

Answer: Before I can answer what rates to use, you need to determine the volume you are actually applying. As hard as you have worked on the problem, you certainly should have had much better results. From reading your e-mail, I think your rates are too low and that is why you are not getting better results. The following is a cheat sheet for how much chemical to put into a hand or backpack sprayer. Please compare what you have been adding to the amounts on this sheet and then we can visit more about what to do next.

The following is information prepared by Dr. Rod Lym called, Cheat Sheet for Herbicide Mixtures.

This can also be found at the on-line version of the ND Weed Control Guide (A15).

 

Handgunning & Back pack spraying

Figure roughly 50 gal/acre application rate unless otherwise calibrated

 

Boom Spraying

Mix to calibrated rate of gallons per acre output of spray unit being used.

For MOST handgun & backpack applications, these rates apply:

2 qt/acre = 1.28 oz x # of gallons water = oz of herbicide for mixture

(Eg. For a 3 gallon backpack: 1.28 x 3 = 3.84 )

1 qt/acre = 0.64 oz x # of gallons water = oz of herbicide for mixture

(Eg. For a 3 gallon backpack: .64 x 3 = 1.92 or 2 oz herbicide)

1 pt/acre = .32 oz x # of gallons water = oz of herbicide for mixture

(Eg. For a 3 gallon backpack: .32 x 3 = 0.96 or 1 oz herbicide)

 

TORDON 22K:

1 qt/acre rate =0.64 oz gal of water : 2qt/acre rate=1.25 oz/gal of water

3 gallon backpack: 2 oz Tordon 22K(1qt): 4 oz Tordon 22k (2qt)

15 gallon sprayer: 9.5 oz Tordon 22k(1qt): 19 oz Tordon 22k (2qt)

25 gallon sprayer: 16 oz Tordon 22K(1qt): 1qt Tordon 22k (2qt)

50 gallon sprayer: 32 oz Tordon 22k(1qt): 2qt Tordon 22k (2qt)

 

WEEDAR 64 (2,4-D):

1 qt/acre rate =.64oz/gal of water;

2 qts/acre rate =1.28oz/gal of water

3 gallon backpack: 2 oz Weedar 64 (1qtl); 4 oz Weedar 64 (2qt)

15 gallon sprayer: 9.5 oz Weedar 64(1qt): 19 oz Weedar 64 (2qt)

25 gallon sprayer: 16 oz Weedar 64 (1qt); 32 oz Weedar 64(2qt)

50 gallon sprayer: 32 oz Weedar 64(1qtl); 64 oz Weedar 64(2qt)

 

WEEDAR 64 + TORDON 22K: 1 qt Weedar 64 + 1 pt Tordon 22K/ac

3 gallon backpack: 2 oz Weedar 64 + 1 oz Tordon 22K

15 gallon sprayer: 10 oz Weedar 64 + 5 oz Tordon 22k

25 gallon sprayer: 16 oz Weedar 64 + 8 oz Tordon 22K

50 gallon sprayer: 32oz Weedar 64 + 16 oz Tordon 22k

 

Adjuvant/Surfactant Mixing

Generally surfactants are mixed at 1 pint/50 gallons water unless otherwise stated.

Examples:

R-11 at 1 pint/50 gallons

Syltac at 1 pint/50 gallons

MSO at 1 pint/50 gallons

Hasten at 1 pint/50 gallons

Non-Ionic 90 at 1 pint/50 gallons

3 gallon backpack: .96 oz (round to 1 oz)

10 gallon sprayer: 3.2 oz (round to 3 oz)

15 gallon sprayer: 4.8 oz (round to 5 oz)

20 gallon sprayer: 6.4 oz (round to 6.5 oz)

25 gallon sprayer: 8 oz 50 gallon sprayer: 16 oz (1pint)

Rod Lym

NDSU Weed Science

Noxious and Invasive Weeds


This site is supported in part by the Crop Protection and Pest Management Program [grant no. 2017-70006-27144/accession 1013592] from the USDA National Institute of Food and Agriculture. Any opinions, findings, conclusions, or recommendations expressed are those of the website author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture.

USDA logo

Creative Commons License
Feel free to use and share this content, but please do so under the conditions of our Creative Commons license and our Rules for Use. Thanks.