Monday, December 31, 2012

Using Surfactants with Herbicide Applications

Surfactants are chemicals that change the physical properties of liquid surfaces. Although soap and household detergents are surfactants, they are not as effective as the commercial agricultural ones.  When added to herbicides, surfactants will:                          

  •  Enhance the spread of the spray droplets on the leaf surface. This increases the effectiveness of the herbicide.
  •  Enable the herbicide to be more rain resistant.
  •  Reduce the rate of drying of the spray solution.
  •  Aid in the suspension of insoluble pesticides like powders in water.
  • Reduce the proportion of very fine droplets, thus reducing spray drift.
Gardeners should always apply herbicides (any pesticide for that matter) at the recommended label rate. Overdosing is a common error - thinking that a higher concentration will result in a better or quicker kill.  This, however, will result in unnecessary expense, an unnecessary release of herbicide into the environment, and, ironically, poor weed control. With systemic foliar herbicides, an effective weed kill depends on the herbicide being trans-located (moved) from the leaves to the roots. Too high a rate will close down the system and the necessary amount of herbicide will not reach the root system.