CHEMICAL WEED CONTROL IN THE ORCHARD 



The elimination of grass and weeds under fruit trees may aid materially to 

 tree growth and mouse control. However, successful use of chemical weed killers 

 requires close attention to details. With chemical weed control it is necessary 

 to - read the label - follow the instructions - apply only on crops specified - 

 not apply more than the suggested amount - make applications only during sug- 

 gested seasons - and calibrate your sprayer to insure proper rate of application. 



Sprayer Calibration 



Calibration of the sprayer is as important as following the directions on 

 the chemical label. Over-dosage can cause injury to trees. Speed of sprayer, 

 nozzle spacing, application rate and discharge rate per nozzle are the four 

 major factors to consider in calibrating a farm sprayer. Farm equipment dealers 

 can furnish information on sprayer calibration and proper nozzling. 



If using a hand gun, the rate of discharge can be found by determining the 

 time required to fill a container of known gallonage. This procedure will enable 

 the grower to time the application for each tree. 



If the amount of herbicide desired per acre is dissolved or suspended in 100 

 gallons of spray solution, then each gallon of spray solution should cover the 

 number of trees listed in Table 1. 



Table i . Number of trees to cover with 100 gallons or with 1 gallon of spray 

 solution when applying at the rate of 100 gallons per acre and spraying the 

 stated number of feet from the tree trunk on all four sides of the tree. 



Many of the herbicides used for weed control are wettable powders that form 

 suspensions rather than true solutions. If agitation is not sufficient, the 

 materials will settle out and result in a higher concentration of herbicides in 

 the bottom of the tank. This, in turn, could cause serious Injury when the 



