BUREAU OF ENTOMOLOGY AND PLANT QUARANTINE 57 
guava in a comparatively dry environment on the south slope of 
Kilauea at an elevation of about 2,500 feet. 
The reductions in the substantial infestations at median elevations 
were comparable to those obtained in the Opaeula Gulch experiment. 
The cost of the Hamakua operation, exclusive of strictly research 
items, averaged about 25 cents an acre per year. 
The much smaller Kilauea experiment failed to produce any con- 
sistent reductions in infestations because of frequent and unantici- 
pated migrations of flies into the small test area. More than 100,000 
flies were caught in a trap located at an elevation of 3,600 feet and 
y 2 mile from the nearest fruits. 
Smooth Cayenne pineapples not a sastisfactory oriental fruit fly host 
An extensive study in Honolulu showed that the smooth Cayenne 
variety of pineapple, the principal commercial variety in Hawaii, 
cannot be considered a satisfactory oriental fruit fly host even though 
this fly deposits a few eggs in it under field conditions. However, 
normal flies do develop in certain experimental pineapple varieties 
and hybrids. Xo adult oriental fruit flies were reared from more 
than 10 tons of Cayenne pineapples collected in fields throughout the 
Hawaiian Islands/ Only rarely was a fruit fly able to complete devel- 
opment in several hundred whole pineapples in each of which thou- 
sands of eggs were laid under forced conditions. These results have 
led to release of the smooth Cayenne variety from treatment require- 
ments. 
Mainland climates in which fruit flies might survive studied 
A second series of simulation-of -climate studies was initiated in 1952 
in cooperation with the University of California Agricultural Experi- 
ment Station to study fruit fly development in climates typical of El 
Centro, Auburn, and San Jose, Calif., Houma, La., and Orlando, Fla. 
The Mediterranean fruit fly, oriental fruit fly, and melon fly, the three 
fruit fly species in Hawaii that are of potential importance to main- 
land agriculture, were included in the new studies. 
Uninterrupted development of all three fruit flies throughout the 
simulated winters was possible only in the Houma and Orlando cabi- 
nets. The Mediterranean fruit fly developed at a faster rate, but was 
not able to attain as high population levels as the other two flies. The 
melon fly and Mediterranean fruit fly proved to be somewhat more 
tolerant of low temperatures than the oriental fruit fly. This agrees 
with previous field observations. 
Bioclimatic studies now completed indicate that all three fruit flies 
could survive very well in some parts of Florida and in the Gulf Coast 
area of Louisiana. Their capacity to maintain themselves in Cali- 
fornia would probably depend upon the extent to which they could 
bridge over periods of unfavorable winter weather as adults, or as 
pupae in the soil. Establishment, reproduction, and development of 
all three flies undoubtedly could occur in any mainland area during the 
most favorable seasons of the year if suitable host material Avere 
available. 
Cooperative biological-control program continued 
The Territorial Board of Agriculture and Forestry continued to 
propagate and distribute several of the introduced parasites and carry 
on recovery studies. The University of Hawaii continued its parasite 
