Toxicity of Zectran insecticide to several wildlife species

Abstract

Zectran® (4-dimethylamino-3,5-xylyl methycarbamate), all insecticide proposed for control of spruce budworm, Choristoneura fumiferana (Clemens), was tested against 16 species of pen-reared or captivity-acclimated animals to determine its toxicity and potential hazard to wildlife. The acute oral LD 60 values in mg/kg were: lesser sandhill crane, Grus canadensis canadensis L.., 1.0-4.5; Canada goose, Branta canadensis L.., 2.64; mourning dove, Zenaidura macroura L.., 2.83; mallard duck, Anas platyrhyndura L.., 3.0; coturnix quail, Coturnix coturnix japonica (Teminck & Schlep get), 3.21; mallard duckling 4.2; ring-necked pheasant, Phasianus colchicus L.., 4.5; house finch, Garpodacus mexicanus (Müller), 4.76; chukar partridge, Alectoris graeca (Meisner), 5.24; domestic pigeon, Columba livia (Gmelin), 6.47; sharp-tailed grouse, Pedioecetes phasianellus L.., 10.0; albino Sprague-Dawley rat, Rattus noruegicis (Fischer), 14.1; domestic goat, Capra aegagnzs L., 15.0-30.0; mule deer, Odocoileus hemionus (Rafinesque), 20.0-30.0; house (English) sparrow, Passer domesticus 1.., 50.4; and bullfrog, Rana catesbeiana (Shaw), 283.0-800.0. In general, birds were more susceptible to single oral doses than mammals and reacted more quickly to intoxication and were more quickly affected. In both groups, the first easily recognized symptom of Zectran poisoning was an increase in the respiratory rate. Deaths appeared to occur from respiratory failure following tachypnea and Cheyne-Stokes respiration. Zectran did not show any marked cumulative effect in subacute oral tests with mallards, chukars, and mule deer. The animals were able to tolerate up to about 40% of a single oral LD 50 dose per day for 30 days, and there was some evidence of a low degree of acquired resistance. Zectran applied dermally to albino New Zealand rabbits, Oryctolagus cuniculus (Lilljeborg), at 2000 mg/kg produced no discernible effects. The reproduction of chukars surviving repeated daily doses of Zectran was similar to that of controls. Low application rates, rapid degradation, low dermal toxicity, and the low degree of cumulative toxic action indicate that little hazard to wildlife should result under field conditions, even though Zectran is highly toxic in acute oral tests.