The effect of benomyl and some related compounds on Lumbricus terrestris and other earthworms

Abstract

Earthworm populations in apple orchard plots sprayed with benomyl and thiophanate‐methyl were greatly reduced. Lumbricus terrestris, a surface‐feeding species, was not found in the treated plots. Captive worms would not feed on leaf material with spray deposits of benomyl, MBC and thiophanate‐methyl at 1.75 μg/cm2, and feeding was significantly reduced when deposits were 0.87 μg/cm2. There was 100 % kill of worms in pots of soil within 14 days following a benomyl drench at the rate of 7.75 kg/ha, and a 60 % kill following a drench at the rate of 1.55 kg/ha. Worms immersed for 1 min in benomyl suspensions of 0.05 or 0.5 % died within 27 and 13 days respectively; those immersed in lower concentrations would not feed for 2 weeks but eventually did so. It is suggested that the lethal effects of benomyl may be due to anti‐cholinesterase activity of the carbamate moiety of the molecule.

A history of facial eczema (pithomycotoxicosis) research

“…Benzimidazole fungicides were reported to have adverse effects on earthworm populations in orchard di Menna et al-History of facial eczema research 365 soils (Stringer & Wright 1973). Wallace (1976) found no change in them after application of 0.15 or 0.30 kg a.i./ha carbendazim, thiophanate-methyl or benomyl, rates much lower, however, than those used in orchards.…”

The Effects of Toxic Chemicals on Earthworms

“…Immersion Test. There are some reports in the literature on testing the toxicity of chemicals to earthworms by immersing them in dilute solutions of chemicals for set periods of time, then transferring them to clean soil to assess mortality (Goffart 1949;Martin and Wiggans 1959;Stringer and Wright 1973;Stenersen 1979a). These tests give very reproducible results and an LCso can be calculated for any species of earthworm, but this dose can refer only to the concentration of a chemical in the test solution and cannot be related to a dose in soil.…”

“…Many workers have applied chemicals to soil and exposed earthworms to them in containers in the laboratory. Such tests have usually been in boxes Hoy 1955) or in pots (Heungens 1969;Caseley and Eno 1966;Atlavinyte 1975;Agarwal et al 1978;Stringer and Wright 1973;Kale and Krishnamoorthy 1979;Lofs-Holmin 1980;Hamilton and DindaI1989b). Such soil tests in containers usually provide more consistent and reproducible results than field tests, because standard numbers of a single species are exposed in a uniform medium, in which the worms are in intimate contact with the medium containing the chemical.…”

Effets de preparations commerciales de benomyl, mancozebe, sulfate de cuivre et dichlofluanide sur la fecondite de Drosophila melanogaster meigen

“…Un effet phago-répulsif du bénomyl a été signalé chez les vers de terre (Stringer et Wright, 1973) et les pucerons (Bailiss étal, 1978). A l'inverse, chez la drosophile, il ne semble pas y avoir d'effet répulsif du Benlate® vis à vis du comportement alimentaire : les réserves sont en effet suffisantes pour assurer la production des oeufs puisque le taux de ponte sur le milieu non traité n'est pas affecté de façon significative au moins pendant les 3 premières semaines de traitement.…”