Young and adult quail and pheasants were fed diets containing DDT.Chemical analysis of tissues indicated that quantities of DDT stored were not proportional to total amounts administered nor to duration of exposure, but were related to the severity of toxic symptoms.Concentration of the toxicant in breast muscle of birds dying of acute DDT poisoning was approximately 34 jug./ Gm.in adult quail and 22 jug./Gm.in adult pheasants.

DDT vs.Wildlife Relationships Between Quantities Ingested, Toxic Effects and Tissue Storage*

Avian populations in Hanover, N. H., a town that has sprayed its elms with DDT for many years in an attempt to control Dutch elm disease, were compared with those in Norwich, Vt., a town 1 mile (1.6 km) west of Hanover that has never sprayed. Hanover applied 109 lb DDT/acre (2.1 kg/hectare) in April 1963, then used Methoxychlor in April 1964. Population surveys were taken regularly during spring and early summer of these years, dead birds were collected in both towns, and 106 birds were analyzed for DDT, DDE, and DDD. Severe mortality of both resident and migrant birds occurred in Hanover during spring 1963, and the evidence implicates DDT as its cause. Robin loss was estimated at 70% of the resident population, or 350 to 400 individuals, but mortality among other species of widely varied feeding habits was also substantial. Feeding habits suggest that some birds acquired the toxicant by eating living insects carrying DDT, presenting the paradox of survival of the intended DDT victims, and death, instead, of insectivorous birds. Organ and whole bird analyses are presented and criteria for establishing cause of death are discussed. Most of the DDT had been converted to DDE and DDD, and residues were found in all organs analyzed. Robin mortality was reduced, but not eliminated following Methoxychlor application in 1964; these losses were believed caused by residual DDT in the soil. There was no evidence DDT poisoning among other species in 1964, though the dead birds collected were not analyzed.

Bird Mortality Following DDT Spray for Dutch Elm Disease

In Hanover, New Hampshire, where elms were sprayed with DDT, 151 dead birds were found; 10 dead birds were found in Norwich, Vermont, where no DDT was used. Chemical analyses of dead birds, observation of symptoms of DDT poisoning, and a population decline after spraying all indicate severe mortality among certain species in Hanover.

Bird Mortality after Spraying for Dutch Elm Disease with DDT

With the development of many potent chemicals in the years since World War II there has been a dramatic increase in the large scale chemical control of insects and plant diseases. Scientists were quick to caution that the widespread application of toxicants of unknown toxicity to most forms of life might well bring about undesirable mortality or even disruption of ecological balances between populations (Cottain & Higgins 1946; Storer 1946). The present study was undertaken from September 1950 to November 1951 to determine the effects of the agricultural use of two insecticides, DDT and Parathion, on populations of Wood Mice (Peromyscus leucopus) living in the wooded areas adjacent to the crop lands. Although a considerable body of data exists relating to the effects of the newer insecticides (especially DDT) on animal life, there are only a few brief studies concerned with their effects on manmmals. There are no fiejd studies dealing with the effects of Parathion, a recently commercialized insecticide, on vertebrates. Furthermore, no investigations have been reported concerning the relation of vegetable crop insecticide practices, where treatments are more frequent and dosage rates considerably larger than those generally used in mosquito or forest insect control, to associated vertebrate populations. The Wood Mouse, because it was the most frequently trapped maimmal in the wooded areas adjacent to the crop lands, was chosen as the experimental animal. The common names used for species of the genus Peromyscus follow the suggestions of Dice (1937a). Thus White-footed Mouse is the generic name and Wood Mouse is the name of the present species, P. leucopus. Field applications of insecticide may affect animals in many ways. The animal may take the insecticide PAGE

Populations of the wood mouse (peromyscus leucopus) subjected to the applications of

Populations of the Wood Mouse (Peromyscus leucopus) Subjected to the Applications of DDT and Parathion

Dutch elm disease, the causal agent of which is a fungus, Ceratostomella ulmi, is spread from tree to tree by certain bark beetles of the family Scolytidae. In eastern United States two important carriers are the native elm bark beetle (Hylurgopinus rufipes) and the smaller European elm bark beetle (Scolytus multistriatus). In the area of this study the latter is of greater importance. Control of the disease involves control of the beetle vectors which introduce spores of the fungus at the time of feeding. Spraying programs are based on the application of sufficient DDT to elm trees to kill the bark beetles before feeding takes place. Since adult beetles emerge and fly to new trees during several spring and summer months, it is necessary to make two applications of spray in order to provide residual amounts during this period. The first is put on before the leaves are developed in the spring and the residual DDT is presumed to remain effective until the time of the second application in July. Preliminary investigations by the Bureau of Entomology and Plant Quarantine indicated that this procedure was an effective means of safeguarding valuable shade elms. However, frequent reports of bird mortality were received and it appeared advisable to review the program in terms of its effect on songbirds and other wildlife. This report summarizes results of the first summer's work on the problem. While the information was obtained from investigations in Princeton, New Jersey, the results would appear to be applicable to the Dutch elm disease problem as it exists elsewhere in the nation and

Allen H. Benton

Papers

Effects on wildlife of DDT used for control of Dutch elm disease