Interaction of alfalfa plant height and insecticide carrier application rates on beneficial arthropod populations

Abstract

Spray coverage, as measured by water-sensitive paper at the soil surface, indicates that plant height significantly affected coverage while spray volume had little effect. Methomyl and fenvalerate insecticides applied to different alfalfa heights at various carrier volume rates reduced arthropod populations even at lower application volumes. Carrier volume had little impact on the level of arthropod reductions in each plot. Plant height also showed little influence on arthropod mortality. Within the limits of effective pest control there appears to be little potential for reduced impact on beneficial species resulting from refined insecticide carrier volume rates in alfalfa.