Nozzle discharge Equivalent Ratio of weed killer 



per discharge to water to apply 1 pt. 



100 sq. ft. per acre weed killer per acre 



1/2 pint 27 gal. 1 pt. in 27 gal. water 



1 pint 55 gal. 1 pt. in 55 gal. water* 



1-1/2 pints 82 gal. 1 pt. in 82 gal. water 



1 quart 110 gal. 1 pt. in 110 gal. water 



NOTE:--The volume of water is given to the nearest gallon. 



*A mixture of 1 ounce (or 2 standard kitchen measuring tablespoons) of 

 weed killer in 3 gallons of water is approximately equivalent to an applica- 

 tion of 1 pint of weed killer per acre at a nozzle discharge rate of 1 pint 

 per 100 square feet. One pint = 16 fluid ounces = 2 cups = 32 tablespoons. 



EFFECT OF WEATHER CONDITIONS ON SPRAYING 



Weather conditions have important effects on results obtained and 

 hazards involved in spraying with herbicides. 



1. Wind 



Winds cause improper distribution of herbicides andgreatly increase the 

 hazard of damage from drift to sensitive crops in nearby fields or gardens. 

 Ground applications of herbicides seldom should be made during winds of 

 more than 10 to 15 miles per hour. Applications by airplane should stop 

 when winds become stronger than 6 to 8 miles per hour. 



The herbicide 2,4-D and other phenoxy herbicides never should be applied 

 when wind of any velocity is blowing across the area to be sprayed toward 

 nearby valuable sensitive plants. 



2. Humidity 



High or moderate humidity increases the effectiveness of most herbicide 

 applications to foliage because it reduces losses of spray from evapora- 

 tion and aids absorption of the chemicals by weed foliage. Low humidity, 

 on the other hand, reduces the effectiveness of herbicide sprays by in- 

 creasing the rate of evaporation. The disadvantages of low humidity can 

 be overcome partially by using oil, or oil-water emulsions as spray solu- 

 tions, instead of water. 



3. Temperature 



Moderate temperatures ranging from 70° to 85°F. are favorable for spray 

 applications of most herbicides. Low temperatures during the week before 

 spraying often slow plant growth and retard herbicidal activity. High tem- 

 peratures increase losses of herbicides that are volatile and increase the 

 possibility of injury to crops from selective herbicides. The carbamates, 

 dinitro compounds, and high-volatile esters of 2,4-D, 2,4,5-T, and other 

 phenoxy compounds volatilize rapidly at temperatures above 80° F.At tem- 

 peratures above 95° F., even the low-volatile esters of 2,4-D and other 

 phenoxy compounds become significantly volatile. Generally, all herbicidal 

 spray treatments are avoided when the temperature is above 95° F. 



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