Abnormal Increase of Coccus hesperidum in Citrus Groves Treated with Parathion1

Abstract

The scale is normally controlled by entomophagous insects. High-volume applications or high dosages of parathion tended to produce higher populations of soft (brown) scale than did low-volume applications or low dosages. Multiple applications of parathion also caused greater populations than single applications. Parathion-oil sprays did not cause as great increases as did parathion alone.