330 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1953 



yet unknown enemies of prickly pears, studying those preserved in 

 museum collections, as well as the living ones in the field. The most 

 favorable places for these investigations vrere Argentina and the 

 United States, where the great natural stands of "pears" existed. 

 Some 150 to 160 different kinds of insects injurious to the cacti were 

 found, of which 50 proved to be new to science. Twelve of the most 

 promising ones were introduced, and of these one, Cactoblastis cac- 

 torum, described in 1885 from South America, proved so successful 

 that further introductions were unnecessary. From an original ship- 

 ment of about 2,800 Cactohlastis eggs in 1927, 10 million were reared 

 in the next 2 years. In the course of 6 years 3 billion eggs were 

 released. The cactuses literally disintegrated before the onslaughts 

 of the Cactoblastis grubs feeding within their tissues. Within 15 

 months after the first trial liberation, huge stands of cactus lay rotting 

 on the ground and in the next 7 years the last large area occupied by 

 the pears collapsed. By 1940 less than 100,000 acres were believed 

 to be infested with patches of dense or moderately heavy cactus 

 growth, whether of regrowth or seeding origin, as compared with the 

 hundreds of square miles of a few years before. 



In Queensland, the worst -affected state, it would have cost from 

 four to five hundred million dollars to have cleared the infested areas 

 of prickly pears by poison and mechanical means. Following a care- 

 ful study of the problem, and, I would emphasize again, especially 

 the taxonomic literature bearing on it, by introducing and distributing 

 eggs of Cactoblastis^ the Commonwealth Prickly Pear Board accom- 

 ])lished the task at a cost of less than a million dollars. Thus, the 

 formerly useless acreage regained for settlement because of its suit- 

 ability for grazing, dairying, and agricultural purposes became an 

 asset valued at 40 to 50 million dollars, to say nothing of the worth of 

 new improvements and the future yield of the land, which, in time, 

 will amount to many times its present value. Moreover, the benefits 

 of the Australian experiences extended to South Africa and India, 

 where prickly pears had also been giving considerable trouble. 



The Australian entomologists give due credit to the work of the tax- 

 onomists who preceded them in the study of cactuses and cactus insects 

 for their share in the accomplishment of this latter-day miracle, but 

 who could have foreseen 65 years ago that the then published descrip- 

 tion of an insect found to be new by an Argentine zoologist making 

 known to science the animal life of his part of the world would, half a 

 century later, be instrumental in saving a continent from a pest run 

 wild? 



INSECT QUARANTINE 



To prevent such unwitting introductions as this cane borer, the 

 prickly pear, and other pests, our Department of Agriculture has a 



