SCREWWORM ERADICATION—KNIPLING 413 
The opportunity for a more reliable experiment was afforded when 
arrangements were made for a cooperative program on Curacao in the 
Netherlands Antilles, an island of 170 square miles isolated by 40 miles 
from any other land area. An agreement was developed between the 
Governor of Curagao and the Administrator of the Agricultural Re- 
search Service to undertake a screwworm eradication experiment. 
A. H. Baumhover, who was in charge of field tests in Florida, con- 
ducted pretreatment surveys. Plans were made to rear and irradiate 
the screwworms at the Orlando, Fla., laboratory of the Entomology 
Research Division and then ship the pupae by air express to Curacao 
for distribution of the emerging flies. Over-all plans for the experi- 
ment were developed by R. C. Bushland, A. W. Lindquist, and the 
writer. Dr. Bushland was in charge of the entire program. A. H. 
Baumhover and B. A. Bitter, veterinary officer on Curacao, were in 
charge of the work on Curacao, and A. J. Graham and D. E. Hopkins 
were in charge of screwworm production in Florida. These indi- 
viduals, who worked directly on the program, as well as several other 
assistants deserve great credit for their extraordinary efforts in the 
conduct of this program. 
The eradication attempt was started on August 9, 1954. Sterile 
screwworm flies were released on Curacao from airplanes at the rate 
of about 400 sterile males per square mile per week, which provided an 
estimated ratio of 3 or 4 sterile to 1 fertile insect in the population. 
Table 1 shows the results of egg-mass collections on host animals 
exposed in 11 locations on the island. The complete life cycle of the 
screwworm during warm weather requires about 3 weeks. It is indi- 
cated, therefore, that eradication was achieved in about four genera- 
tions. These results were more striking than any of us had hoped for. 
The population decline followed closely theoretical trends that had 
been calculated. 
TaBLE 1.—Fertility of screwworm fly eggs and decline in number of egg masses in 
the eradication experiment on Curacao 
Number of egg masses | Percent of 
Weeks after start of experiment sterile 
egg masses 
Fertile Sterile 
TU! 2 Ee La aa 2 a ee 15 34 69 
2 AREER ne CU ne SN DAM A a nk ak Es SS 17 38 69 
Sede et er Pa ears) JES 1) Qineet aeene AE IRE 6 fs RECRE em Me ge oe 17 36 68 
Ee APU PRICE Pe Wise a A ie Ge eh 10 Biel 79 
EF ag AC cen Ra RL Barge Up npc 0! RU ag Re Im a at 7 42 86 
Qi Be Mou res OO Vive ee be Ly eee ee eet Fe ARY ie ee EES 3 23 88 
ie ees eet Ant MORN A ete WA Pe ae te Ta AB 0 10 100 
GS eal. Son ERLerte ea Renn Sophy a aN preter ale TY se yaranee e 0 12 100 
CO] 2 Pal abies ae Beste SOTO OREO ok a Res BU 2h Ri: ed elo a Ogle Bua JOsleeh= S24 22 
