An intensive field trial to assess hazards to birds and mammals from the use of methiocarb as a bird repellent on ripening cherries

Abstract

: A field trial was carried out in Kent, UK, in 1980, to assess the possible hazards to wildlife of methiocarb used as a spray to protect ripening cherries from damage by birds. A broad range of studies was undertaken on a single site subjected to a series of five applications. Ground deposition was measured by analysis of strips of chromatography paper and petri dishes placed between lines of trees. Airborne drift was measured on targets up to 11 m above the ground, and methiocarb residues were measured in samples of cherries. Birds were captured by intensive mist-netting throughout the trial, and breeding success was monitored in nest boxes and natural nest sites. Livetraps were set to catch small mammals in the orchard on five occasions during the trial. Systematic searches for possible casualties were made, resulting in the discovery of 21 birds found dead or incapacitated. Levels of activity of plasma, liver and brain esterases were measured in samples taken from several species, and liver slices from House Sparrows, Starlings and Thrushes were examined histologically for signs of cell damage. Samples of breast muscle tissue from Starlings and House Sparrows were analysed by GLC for residues of methiocarb and its principal breakdown product, methiocarb sulfoxide. Overall, the trial revealed that many birds and mammals were exposed to methiocarb, but its effects were largely transient and sublethal. Even a heavy repeated programme of spray applications did not cause any serious hazard to wildlife populations.

Insecticide use: Contexts and ecological consequences

“…It cannot be assumed that other formulations or insecticides exhibit similar effects. An exhaustive orchard study of the effects of repeated liquid sprays of another carbamate insecticide, methiocarb, revealed no ''serious hazard'' to any of the dozens of bird species monitored (Hardy et al, 1993). It seems generally true that in the developed world, following the withdrawal and changes in use patterns of some insecticides, populations of affected bird species have largely recovered (Boatman et al, 2004).…”

Reproduction of cavity‐nesting birds in pesticide‐sprayed apple orchards in southern Ontario, Canada, 1988–1994

“…Where decreased egg and chick survival was found, the compounds of greatest toxicity to reproduction appeared to be the OP and CARB chemicals. However, some studies have reported no effect of OPs on avian reproduction in orchards [4]. Unfortunately, the potential effects on reproduction of residual or‐ganochlorine chemicals (OCs) have not been integrated into studies examining the impact of in‐use pesticides despite the high OC concentrations in soils and wildlife in orchards [5–8] and the known toxicity of OCs to avian reproduction [9, 10].…”

Estimating the probability of bird mortality from pesticide sprays on the basis of the field study record

“…In some cases, birds exhibited temporary paralysis. Because symptom onset is very rapid and recovery (through hydrolysis of bound cholinesterase) also is very fast, avian mortality is thought to be relatively low even at extremely high application rates [29]. Clearly, other products of equivalent toxicity would most certainly have caused extensive mortality at those high rates of application.…”