Mite Control in Redworm Beds

Abstract

Redworm production during 1956 was reduced considerably by heavy populations of mites in commercial beds. Some worm growers experienced losses of production ranging from 80 to 100 per cent. At this time the exact method by which these mites inflict damage is not fully understood. Hyche suggested that some species are predaceous and may attack the worms, while others probably compete with the worms for available food. However, worm growers in the Quincy area consider mites harmful to the worms. Previous tests conducted by Hyche (1956) showed that malathion, parathion, and Metacide effectively reduced mite populations seven days after treatment, whereas Aramite had little or no effect. Malathion at all concentrations and parathion and Metacide at high concentrations significantly reduced worm populations, but Aramite did not reduce the number of worms. These tests indicated that parathion could be used at low concentrations (360 p.p.m.) with no harmful effects to the worms. In 1956 a test was conducted to study the effects of three acaricides and one insecticide on the control of mites in redworm beds; to make general observations of the effects of treatments on the worms; and to determine the species of mites present.