BUREAU OF ENTOMOLOGY AND PLANT QUARANTINE 9 
white group, which appears to be responsible for the most important type of 
disease encountered. Experimental field plots have been laid out in which 
larvae have been inoculated in different ways with disease organisms to deter- 
mine the possibility of utilizing these organisms for the control of the beetle. 
The work with the parasites of the Japanese beetle has been continued. Up 
to and including the calendar year 1935, something over 1,100 colonies of im- 
ported parasites have been released in the field. Of this number, 294 new- 
colonies were released in 1935. During the year, 195 selected colonies were 
surveyed to determine their status, 110 of which showed definite establishment. 
most of these being in a very flourishing condition. Three shipments of new 
material from the Orient were received during the year, 6,372 individuals arriv- 
ing alive and in good condition. Certain of the parasites which are effective in 
oriental countries, especially Centeter clnerea Aid. and Tiphia popilliavora Roh., 
are poorly synchronized with the development of the host under conditions in 
the Moorestown, N. J., area. It is believed that conditions in this respect will 
be better in more northern regions. In order to facilitate the work with para- 
sites in the northeastern part of the United States, a substation has been 
established at Springfield, Mass. This will be used as a center for colonization 
work as well as for studies of the biology of the parasites and of the host. 
To keep in touch with conditions existing in more western areas newly occu- 
pied by the Japanese beetle, an investigator is being stationed in the Middle 
West, where a special study will be made of the local infestations that have 
been discovered at various points, including St. Louis and Chicago. 
Investigations on the Asiatic garden beetle have been restricted, attention 
having been given largely to the development of nonpoisonous repellent mate- 
rials for use in vegetable gardens, where sprays leaving poisonous residues on 
the plants cannot be used. Those showing greatest promise were hydrated lime 
dust and a spray of hydrated lime with aluminum sulphate. 
FRUITFLY INVESTIGATIONS 
In December 1935 the investigational work on fruitflies which are a potential 
menace to the mainland of the United States was brought together in a separate 
division, with field headquarters at Mexico City. Studies have been continued 
at laboratories in Mexico, Hawaii, Puerto Rico, and the Canal Zone. Those in 
Hawaii and Puerto Rico were materially expanded by special funds, largely 
allotments from processing taxes. 
The investigations carried on in Mexico have dealt with several species of 
fruitflies of the genus Anastrepha, with particular emphasis on the Mexican 
fruitfly (A ludens Loew) and A. serpentina Wied. In addition to laboratory 
studies of the type conducted in previous years, field experiments have been 
carried on at Santa Engracia to secure data on the effectiveness of various 
sweetened sprays and attractants used in traps, and to obtain information on 
various hosts and their effect on the abundance of the flies within orchards. In 
these field tests the sweetened sprays containing tartar emetic as a poison 
proved to be more effective than any others tested. Laboratory studies in 
Mexico City have shown that A. serpentina, a fruitfly that has recently ap- 
peared farther north in Mexico, can survive freezing temperatures, can live 
many months, and can reproduce as abundantly as the Mexican fruitfly. 
During the year the investigations conducted in Hawaii wore extended to 
include the melon fly as well as the Mediterranean fruitfly. Experiments to 
determine the effect of low temperatures on the immature stages of the Medi- 
terranean fruitfly that occur in fruit have been continued, and sufficient data 
have been obtained at temperatures of 30° to 32° F. to conclude the test-, at 
these temperatures. In the investigations on baits and attractants during the 
last part of the year special attention was directed to the testing, against the 
Mediterranean fruitfly, of certain protein baits developed in the laboratory at 
Mexico City. The tests so far conducted suggesl that these are three or more 
times as attractive to the fly as any other baits tested. Experiments have been 
carried on to determine the effect of vacuum and fumigation on the immature 
stages of the larvae within various fruits. Many fumigants have been elimi- 
nated: preliminary tests with others, however, suggest their possible usefulness. 
In Puerto Rico various insecticides and attractants developed at other 
laboratories have been tested to determine their effectiveness on the two forms 
of the West Indian fruitfly which occur in that island. The insecticide tartar 
