7S ANNUAL BEP0BT8 OF DBPABTMBNT OF AGHICULTTRE, 1953 
Since the production of spore dust was initiated in i ( .»:;:>. more than 
184,000 pounds of the material have been prepared ai the Bureau's 
Moorestown, X. J., laboratory. 
In cooperation with State agencies. ites including 7,772 acres 
in 55 counties of i States and the District of Columbia were treated 
with milky disease spore dusl in 1952. Since the colonization program 
started in 1939, 1 10,973 sites involving 109,1 L9 acres in 220 count • 
14 States and the District of Columbia have been bo treated. 
Field surveys in 1952 showed that tins disease is well established 
at many sites where it was colonized years ago in Connecticut, Dela- 
ware. Massachusetts, New York, Pennsylvania, Virginia, and West 
Virginia. There is a tendency for the disease to be more active in 
the southern than in the northern parts of the infested area. One or 
more types of the disease have al-o been determined at several sites 
in these States where the organism was not known to have been 
colonized. 
This line of work was placed in an inactive statu- at the end of the 
fiscal year. 
Japanese Beetle Parasites Survive Two Decades 
Tiphda popilliavora* an imported parasite of the Japanese beetle 
grub, has persisted for 20 years in the older infested areas in Xew 
Jersey and Pennsylvania, where the beetle population is now at a low 
level. Field surveys of 106 sites colonized two decades ago sh< 
that this parasite is present at about one-third of these site-. Al- 
though this parasite has persisted, its effectiveness is rather low. 
Tiphia vernalise the most valuable imported parasite of the same 
grub, has been shown by further surveys to be generally distributee! 
and well established over at least 10,000 square miles for some distance 
beyond original points of colonization in Delaware, Maryland, and 
Pennsylvania northward into New York and Connecticut. Experi- 
mental colony units of 100 females each were furnished to Wesl Vir- 
ginia officials U>v release at L5 approved sites in that State, v in 1952 
and 7 in 1953, and 2 similar unite were furnished to Vermont officials 
for release in L953. Bureau personnel also released two experimental 
colonies ai an isolated infestation in Pennsylvania in L952. 
Four experimental colonies of ( . an imported parasite 
of the adult Japanese beet le, were released during 1952, one colony each 
in Massachusetts and Wes( Virginia, and two colonies in New Jersey. 
About 1,700 puparia were collected in the held in New Jersey and stored 
at the Moorestown, X. J,, Laboratory, to provide adult flies for further 
colonizal ion in L! 
This phase of the work was placed in an inactive status at the end 
of the fiscal year. 
Diseases <>f the Japanese Beetle 
Some species of nematodes pathogenic to the Japanese beetle have 
been found to be pathogenic to the European chafer. It was also 
found that bacteria associated with the pathogenic nematodes pro- 
duced antibiotic substances thai could be demonstrated in cultun 
in tissue* of larvae infected With these bacteria or with the nematodes. 
