- 7 



weed to be controlled is in the "full bloom" to "green fruit" stages of 

 growth. Most applications are made too early, and result in good top kill 

 but allow the roots to survive and resprout. Severe injury may result if 

 Roundup^ contacts a fresh wound, the fol iage, or green immature bark of an 

 apple tree, oj- any part of a peach tree. Always carry pruning shears when 

 using Roundup" in an orchard. Immediate pruning of an accidentally sprayed 

 limb will eliminate the risk of herbicide damage to the tree. 



***** 



BOOM SPRAYER CALIBRATION AND USE 



Elden J. Stang 



Department of Horticulture 



University of Wisconsin, Madison, Wl 



There are many ways to properly calibrate a conventional boom-type weed 



sprayer. The principles are the same whether you use a massive field 



sprayer with ^0 nozzles or a simple 2 or 3 nozzle boom for undertree 

 spraying. 



Why calibrate? According to a study by Nebraska agricultural engineers 

 the four most common causes of error in applications of agricultural chemi- 

 cals include: 1) INACCURATE SPRAYER CALIBRATION, 2) incorrect mixing, 3) 

 worn equipment, and '*) failure to read the label. 



Do you really know how to calibrate your sprayer? If you do, fine. If 

 not, or if you would like to check your method, the procedure described 

 below, suggested by Robert Newman and L.K. Binnin, UW-Madison weed scien- 

 tists, is offered for your use. 



The method is simple and accurate. Follow the directions carefully and 

 you can be assured your sprayer is correctly calibrated. 



Calibration Tools You Need 



1. A tape measure, 2 stakes or flags. 



2. A new pressure gauge. 



3. Catch bottles or containers. 



h. An accurate measure, in ounces. 

 5 . A calculator. 



- use the tape measure to measure distance accurately 



- use the new pressure gauge to check the accuracy of the old one 



- use the catch bottle to collect nozzle output 



- measure the output accurately 



- use the calculator to avoid mistakes in arithmetic 



