Some pesticides may have more than one purpose. To kill living things is usually the primary objective, but slowing the growth of the grass may not be far behind. Grass that grows slowly demands less frequent landscaping cutting, thereby lessening the cost of maintenance. I suppose both of these objectives of pesticides, to kill and to retard growth, might be considered related insofar as retarding growth might be achieved by killing some of the grass cells. Something always has to die. I wonder what pesticide thinks to itself when it meets a healthy plant cell being eaten by a ladybug.