BIOLOGY AND CONTROL OF CHIGGERS. 15 
It would appear from ‘this that the dusting with sulphur inside 
the hosiery and underwear is sufficient if it is so applied as to be 
well distributed. Later tests fully demonstrated that a single appli- 
cation was sufficient if well distributed. 
The “ pinch method,” i. e., applying a powder insecticide by pick- 
ing up small amounts with the thumb and fore finger, while well 
adapted for dusting lousy chickens, for example, was observed to 
be both tedious and wasteful, hence other methods were resorted to. 
Application by means of a talcum shaker was made on August 
9, 1919, followed by exposure at Vienna, Va. Examination that 
night showed it to be 100 per cent effective. 
On August 15, 1920, application was made with a pepper shaker. 
A considerable tendency of the sulphur to clog the small holes of 
the top was noticed, but by violent agitation a fairly even appli- 
cation was made. Only the inside of the stockings and the lower 
part of the underwear were treated. Exposure for about 3 hours 
was made in the woods north of Chesapeake Beach, Md. Later 
examination showed 100 per cent efficiency. It should be added 
that if sulphur is dusted by means of a salt or pepper shaker, after 
the operation all unused sulphur should be removed and the con- 
tainer washed. This will prevent the tarnishing of the metal parts 
of the shaker. 
Mr. Flint, of the State Natural History Survey of Illinois, states 
that he has applied sulphur by means of a small bag and also by 
the “pinch method,” with good results. Dr. J. W. Folsom also 
reports good results from sulphur treatment by the “ pinch method.” 
During the summers of both 1919 and 1920 several members of 
the bureau staff tried the use of sulphur, and in every case good 
results were reported and usually complete protection. 
DESTRUCTION OF BREEDING PLACES. 
It is hoped that the observations made on the habits and local 
distribution will enable much more to be done to advantage in de- 
stroying the breeding places of chiggers. Especially is this method 
of attack to be recommended about private dwellings and in poorly 
kept public parks and at summer resorts. Already its feasibility 
has been demonstrated. In and around Washington many chigger- 
infested lots or fields have been automatically rendered free of 
chiggers by turning these to cultivation or cleaning away the rough 
growth. Prof. F. L. Washburn (7/2) has the following to say in 
regard to the effect of cutting down bushy growth in Minnesota: 
Capt. Zimmerman, living on Enchantment Island, Lake Minnetonka, having 
found this pest troublesome on his own island and upon the neighboring Phelps 
Island, has reduced their numbers materially by cutting out much underbrush, 
thus letting in the sunlight. 
