96 
JOURNAL OF ECONOMIC ENTOMOLOGY 
[Vol. 17 
while thoroughly effective in maggot control, actually increased the 
liability to loss from such fungous troubles, while others, notably mer¬ 
curic-chloride solutions, very largely prevented the development of 
such diseases. 
A number of seed-bed diseases have been under observation in the 
course of this work, but for the purpose of the present paper only Rhizoc- 
Table 1. Relation of Different Methods of Maggot Control to the 
Development of Rhizoctonia in Cabbage Seed-Beds 
Number Number Percentage Percentage 
Treatment of of plants infested by infected by 
applications examined maggots Rhizoctonia 
Mercuric chloride 1-1200 . 1 162 33 19 
“ .2 182 11 4 
“ 3 230 3 3 
Tobacco dust. 1 242 34 83 
“ *.2 346 2 89 
“ 3 218 0 79 
Cheesecloth screen. 158 0 66 
Check.No treatment 1426 70 60 
tonia will be considered as the data on this fungus are somewhat more 
complete and serve fully as well to illustrate the principle involved. 
Rhizoctonia is a common damping-off fungus which, with cabbage, is 
primarily troublesome as a seed-bed disease; the young plants being 
attacked at or near the surface of the ground. At the time of transplant¬ 
ing the injured areas may appear as sunken, grayish-black lesions, which 
if extensive enough may girdle and cause the death of the plant; but 
more often result merely in a constriction or weakening of the stems. 
During some seasons this fungus may cause a high mortality among 
young plants in beds where conditions are favorable for the development 
of the parasite. While only a comparatively small percentage of the re¬ 
maining plants may be actually killed, this weakening and dwarfing 
effect is often quite general. Table 1 represents one of a series of tests 
that have been made to determine the influence of the various methods in 
use for maggot control on the development of cabbage seed-bed diseases. 
In this particular instance the seed-bed was located in a rather low 
section of the field which had been planted to potatoes the preceding 
season. During the early development of the plants there was an 
excessive amount of rainfall so that taken as a whole conditions were 
unusually favorable for the development of this type of fungus. 
