Effects of grasshopper‐control insecticides on survival and brain acetylcholinesterase of pheasant (Phasianus colchicus) chicks

Abstract

Abstract-Ring-necked pheasant (Phasianus colchicus) chicks were exposed via contact and/or ingestion to formulations of three insecticides (Lorsban 4E, chlorpyrifos; Cygon 480E, dimethoate; and Furadan 480F, carbofuran) applied to pasture plots at one and four times the rate recommended for control of grasshoppers (Orthoptera: Acrididae) in prairie Canada. Chicks (3 d old) were exposed for 48 h in pens with the sprayed vegetation and were fed either unsprayed grasshoppers or grasshoppers sprayed at the same rates as the vegetation. Control groups were exposed to unsprayed vegetation and received unsprayed grasshoppers. Three replicates were conducted throughout June and early July 1992.Although some signs of acetylcholinesterase (AChE) depression were observed in chicks exposed to insecticides, there was no difference in the number of mortalities among treatment and control groups. Chicks that died during the exposure period gained significantly less weight than survivors in all groups. Among surviving chicks, weight gains of those exposed to the high-rate Furadan treatment consuming sprayed food were significantly lower than those of controls (1.8 vs. 6.6 g/d). Brain AChE activity was lower overall in surviving chicks than in those that died; it was not significantly reduced among chicks that died in any treatment group. Overall, survivors of Furadan-exposed treatment regimes had lower AChE activity than those of Cygon and Lorsban treatments; birds in high-spray-rate treatments of all insecticides had lower AChE activity than those in all low-spray-rate treatments; and birds in all treatments consuming sprayed grasshoppers had lower AChE activity than those fed unsprayed grasshoppers. Food consumption was not affected by any treatment.

ASSESSMENT OF HEALTH AND GROWTH OF RING-NECKED PHEASANTS FOLLOWING CONSUMPTION OF INFECTED INSECTS OR CONIDIA OF ENTOMOPATHOGENIC FUNGI, Metarhizium anisopliae var. acridum AND Beauveria bassiana , FROM MADAGASCAR AND NORTH AMERICA

“…At the age the pheasants were being treated (4 and 9 d old), two grasshoppers were equivalent to approximately 2% of the body weight of the birds. The feeding rate of two grasshoppers per chick per feeding event is in line with the number of grasshoppers found in the diets of chicks of other grassland birds species (Martin et al, 1998(Martin et al, , 2000, and approximately matches the dosing methods used in previous studies (Martin et al, 1996). In field applications (e.g., Johnson & Goettel, 1993, and others summarized by Lomer et al, 2001), complete or near complete infection of grasshoppers has not been observed, although complete or near complete infection of treated grasshoppers is typical in cage tests.…”

“…Uniform, day-old, ring-necked pheasant chicks were obtained from massreared broods at the Brooks Wildlife Center (Alberta Forestry, Lands and Wildlife, Brooks, AB, Canada), using the same methods and source of birds used in previous and subsequent avian toxicity tests with grasshopper insecticides (Martin et al, 1996;Smits et al, 1999). Chicks were maintained in the Controlled Environment Barn, Agriculture Canada Research Facility, Lethbridge, AB, and fed unmedicated duckling starter (21% duck and goose starter crumbles, Unifeed, Lethbridge, AB-21% protein, 3% crude fat, 5% crude fiber, supplemented with vitamins A, D, E) until being exposed to the challenge diets.…”

Chlorpyrifos: Ecotoxicological Risk Assessment for Birds and Mammals in Corn Agroecosystems

“…Data were plotted and linear regressions performed with the aid of SigmaPlot 6 graphics package (SPSS 2000) (Figure 9). Concentration of chlorpyrifos in food items in target fields, such as invertebrates from orchards and row crops exposed to spray formulations (Brewer personal communication;Brewer et al 1997;Frey et al 1994;Gallagher et al 1994;Martin et al 1996) and earthworms from fields treated with the granular formulation (McCall et al 1984), were obtained. As appropriate, available data from other uses of spray formulations were used as surrogates for food items in corn fields or in their borders.…”

“…These concentrations overlap two of the concentrations included in the simulated field tests by Hurlbert et al (1970) in which adverse effects were reported. The effect of chlorpyrifos (as Lorsban ® 4E) on survival and brain AChE of ringnecked pheasant chicks has been evaluated in a field/pen study (Martin et al 1996). The study field was a mixed-grass prairie with predominantly blue grama grass (Bouteloua gracilis) and sage (Salvia sp.).…”

“…For assessment of chronic exposures, the estimated concentrations in grass and broadleaf plants after direct application, grass and broadleaf plants in field borders with chemigation end gun, and fixed-wing aircraft application to short grass all yielded concentrations greater than the NOEL for mallard duck chronic dietary Martin et al (1996) were not used as they were based on food items sprayed under laboratory conditions. These HQs are based on the worst case assumption that the birds will only consume treated food items, however, they give similar conclusions to the acute HQs.…”