122 
our knowledge of the constant occurrence of the Micrococcus in soils 
everywhere, that it is of minor importance in the control of Phyllophaga, 
except possibly under exceptionably favorable ‘conditions, and that it 
can not be used for this purpose artificially. This disease has been 
studied in Porto Rico by Mr. R. H. Van Zwaluwenburg, and his con- 
clusions (79), which agree with our own, are as follows: “The organism 
is present in our soils but its efficiency can not be increased by any prac- . 
tical means, for infection takes place usually only through a bruise or 
cut in the integument of the larva.” 
Funcous DisEasss 
Of the several species of fungus parasites of white-grubs, the so- 
called green muscardine fungus (Metarrhizium anisopliae Metsch. and 
its variety americana Pettit)* is the commonest and most wide-spread 
(Pl. XIII, Fig. 51—57). M. amsopliae was discovered by Metschnikoff, 
in 1878, attacking larvae of Anisoplia austriaca, a white grub of con- 
siderable importance in Europe. It has since been frequently referred 
to in literature and is now known to attack nearly all torms of insect 
life, being apparently cosmopolitan in its distribution. The first indica- 
tion of the disease is a rigidity of the body, and this is followed shortly 
by the appearance of white mycelial threads, first at the joints, and later 
completely covering the body with a white velvety coat. Within a day 
or two the characteristic green spores develop—dark in the case of 
anisopliae and light green in the variety americana. This fungus has 
probably never been artificially employed with effective results on white- 
grubs although it has recently proven somewhat effective in Trinidad 
(64, 76) in the control of the sugar-cane froghopper (Tomaspis varia 
Fabr.). In 1913 the writer applied this fungus in several fields badly 
infested with white-grubs in Wisconsin and Indiana, using corn-meal 
cultures, some of which were grown at the Lafayette Station, but most 
of them furnished by Dr. S. A. Forbes. No results whatever were 
obtained in any case, although the grubs were abundant and the weather 
conditions were favorable to fungus growth. The green muscardine 
has also been used for the control of white-grubs in Porto Rico, and the 
results obtained there, which agree with our own, may be summarized 
from the report of the pathologist, John A. Stevenson (68). “At the 
south coast laboratory at Ensenada the fungus is present to such an 
extent as to seriously interfere at times with the progress of studies on 
the life history of the various beetles attacking cane. On the other hand 
no such success has attended the field trials which have been conducted 
in the neighborhood of Yauca. * * * The fact that it [the green mus- 
cardine fungus] does exist here and has not become epidemic would 
seem to militate against the success of present experiments, especially 
in the light of results obtained to date.” While following the plow we 
have found isolated cases of Metarrhizium infection in grubs of the 
" * Variations in color and size of spores are thought by John R. Johnston (40) 
to depend upon the host or the media, not being of varietal rank, but merely 
indications of different physiological races. 
