58 ANNUAL REPORTS OB DEPARTMENT OF AGRICULTURE, 1933 
establishment, spread, and evaluation studies. The Bureau's contribu- 
tion consisted 01 a few observations on the habit- of established para- 
sites and numerous records of parasitization of fruit flies infesting 
various hosts. 
Parasites recovered for the first time in 1952 included Opiua Xo. 2 
(New Caledonia). Opius No. 3 (Siam), tiyntornosphyrum vndA 
and Tetrastichus dacicida, the latter an African importation. 
Studies by University of Hawaii entomologists and incidental rec- 
ords obtained by Bureau workers showed that the egg-larval parasite 
Opius oophihts continued to be by far the most effective of the intro- 
duced species. The proportion of larvae parasitized by this and other 
parasites was somewhat less during most of 19.VJ than L95L It is 
becoming increasingly apparent that a definite fruit fly problem will 
remain despite the work of natural control agents unless there are 
unexpected major changes in factors affecting fly abundance. 
University of Hawaii studies showed that a fungus [Mucor sp. | is 
an important factor in the mortality of oriental fruit fly eggs. 
Treatments permit movement of fruit from Hawaii 
As a result of the development of ethylene dibromide treatment for 
fruit fly-infested fruits and vegetables, exports from Hawaii to the 
mainland have increased from a few thousand pounds of fresh pine- 
apple in 1948 to more than 2y 2 million pounds in 1952. The volume 
of shipments increased each month during the year. Exports of fresh 
papaya, which may be made following fumigation with ethylene 
dibromide or treatment with vapor heat, increased to 2S3,000 pounds 
during the first 10 months of 1952 despite a strike which stopped ship- 
ments during June and July. 
Although 124 additional materials were screened as fumigants to be 
used against the different fruit flies in products to be moved from 
infested localities none of them proved as effective as ethylene dibro- 
mide. Most effective of the screened materials were hexyl, heptyl 
and octyl iodides, epibromohydrin, methyl chloroacetate, and methyl 
and ethyl bromoacetates. 
Fruit fly investigations in Hawaii were in cooperation with the 
University of California, University of Hawaii, Agricultural Experi- 
ment Stat ions, the Territorial Board of Agriculture and Forestry, the 
Pineapple Research 1 osl it ute, and the Hawaiian Sugar Planters' A - 
ciat ion Experiment Station. 
Mexican Fruit Fly Control 
Most of the citrus fruit in the Lower Rio Grande Valley was har- 
vested and shipped before heavy migrat ion of Mexican fruit tlies from 
northeastern Mexico occurred in L952. Asa result, no sterilization of 
fruit was required. The normal citrus-harvesting season in Texas 
extends from October through May, and larval infestations are most 
frequent ly found from January unt il the close of the harvest tng season. 
The year L952 58, however, was an unusual season in Texas. The 
fruit ciop was extremely Short On account of a previous heavy frost. 
This resulted in an early harvest I )uc to this early harvesl ing of the 
commercial crop, larval Infestations were discovered in Texas only in 
fruit retained for local consumption. Operation of several thousand 
fly trap- in tic groves, however, indicated the usual migration of flies 
from Mexico. The production of a normal crop would have meant 
