K. M. Harris. 1969. Population increases of Steneotarsonemus pallidus (Banks) following spray applications of dimethoate. Plant Pathology 18 (3): 113-115. 77

Keywords: Field experiments on chemical control of Steneotarsonemus pallidus on Michaelmas daisies (Aster novi‐belgii) at Wisley in 1967 and 1968 showed that massive increases in mite populations follow single spray appl.ications of dimethoate. Published reports of similar effects on strawberries indicate that predators are adversely affected by some organophosphorus pesticides. Predators were present on Michaelmas daisies at Wisley and may have been affected by dimethoate but there may also be some biochemical or other effect on the host plant that increases mite fecunditv, acaricide induced pest resurgence.