Human bot fly.

Most of the foregoing examples of eradication occurred before the development of the new insecticide's and equipment. Several other pests could doubtless have been wiped out except that the necessary measures would have been considered as interference with an individual. For example, human lice could easily be eradicated in this country but a Nation-wide compulsory physical examination would be necessary to find the few infested persons. The boll weevil, which has caused millions of dollars of damage to cotton every year, could be eradicated quickly by establishing a series of zones across the Cotton States in which no cotton could be grown for a while. The farm adjustments and loss of income for even a year to ginners, oil millers, and others would keep any State from adopting the necessary legislation, however.

If we examine again the insect problems of the United States and take into consideration the value of the new chemicals and machines, very likely we would agree on the practicability of a full-scale onslaught against other pests, especially those that attack livestock.

One of the first would be the two species of cattle grubs, which cause an estimated annual loss in the United States of 100 million to 300 million dollars. The eradication of both from Clare Island by the slow painful method of squeezing the grubs out of the animals by hand shows that the present convenient and inexpensive chemical treatment could be effectively used for eradication if the public demanded it.

Any community that undertakes to eradicate cattle grubs might well include cattle lice in the program; the cost of eliminating the two groups of pests would be little more than the cost for one alone. Cattle lice were almost unknown in parts of the South during the compulsory tick-eradication program, and it seems certain that present methods of controlling lice would result in quick eradication in any areas that undertake to do so.

The screw-worm does not ordinarily overwinter north of Florida and the extreme southern part of Texas, but it occurs much farther north in mild winters. From those areas it spreads north each season. If it would be stamped out in Florida during a cold winter, all the Southeastern States would be freed from attacks. Eradication seems quite possible technically, especially with the improved treatments that kill the adult flies and the larvae, but the presence of wild hogs and other wild animals in remote areas would make eradication more difficult.

The effective control of the sheep bot fly with a Lysol nose drench makes It possible to get rid of the pest, because it overwinters only in the nasal passages of sheep. Associations of sheep raisers might well consider a combined program to eradicate the sheep-tick and the sheep bot fly at one time.

The reduction in the number of horses on farms in the United States has made the eradication of the horse bot fly, nose bot fly, and throat bot fly only a question of whether there is enough interest to justify such an undertaking. Controls are effective and areas could be cleaned up quickly in a vigorous campaign.

The eradication in any State of the several livestock pests I have mentioned probably would not be too difficult technically, but much of the value would be lost unless the programs were undertaken on a national or continental basis, for some of the pests would quickly spread back from other areas. Required, therefore, would be the concerted, simultaneous effort of the States to bring about the desired results. Pests more or less restricted to the bodies of their hosts, such as cattle lice, the sheep bot fly, and the sheep-tick, might be eradicated within limited areas and their reintroduction prevented by strict enforcement of quarantine measures, but I think it would be more desirable, even so, to have a Nation-wide program.

That is a challenge to entomologists and farmers. No eradication project can succeed, no matter how effective the controls devised by the entomologist, without the full cooperation of farmers in initiating and supporting the necessary enforcement laws and regulations and in carrying out the recommendations.

CLAY LYLE is director of the Mississippi Agricultural Experiment Station and Agricultural Extension Service and dean of the School of Agriculture of Mississippi State College. Before he assumed those positions on July 1, 1951, he was entomologist for the Mississippi Agricultural Experiment Station, entomologist and executive officer of the State Plant Board of Mississippi, professor and head of the Department of Zoology and Entomology, and dean of the School of Science of Mississippi State College. He began his entomological work in Mississippi 1920. He has degrees from Mississippi State College and Iowa State College.