The immediate and long-term effects of the herbicide MCPA on soil arthropods

Abstract

Plots on arable land in southern England that had received an annual application of MCPA herbicide for 10 out of 13 years between 1951 and 1963, and similar untreated plots, were sampled to see whether there were any long-term or short-term effects on the arthropod fauna. Samples were taken before and after spring sowing, before and after spray application of the herbicide, and about a month later when weed counts were made. The fauna was divided into orders or suborders initially, and no differences between treated and untreated plots were detected either at the beginning of the season, as a residual effect from previous years, or in the period immediately following spraying. The Acari population was then analysed in more detail for possible qualitative differences between treatments, and the recorded numbers of 12 common species and two genera in treated and control plots were examined. No effect that could be attributed to the use of MCPA was found. The density of the fauna is discussed in relation to other soil arthropod surveys, and the wealth of Acari species is commented on. A list of the species of Acari and Collembola collected is appended.