June, ’23 
WEIGEL AND DOUCETTE: STRAWBERRY ROOTWORM 
285 
The next spring a light infestation was still evident but the replacing of 
all the plants during the summer ended the depredations and there 
has been no recurrence of the insects since that time. 
A very heavy infestation was encountered in a large establishment 
of 250,000 plants at North Wales, Pennsylvania. The vast number of 
beetles present during the summer of 1919 was shown by the payroll for 
several school boys, who collected as many as 60,000 beetles in one 
week, at a cost of $150.00, or 25 cents per hundred beetles, and gathered 
several hundred thousand more during the subsequent period in which 
they were employed. While this practice destroyed many of the in¬ 
sects, nevertheless a large number escaped collection. A dust mixture 
containing 10 parts arsenate of lead, 40 parts air-slaked lime, and 50 
parts sulphur was applied regularly throughout the summer of 1920. 
This was the only control measure followed that year, and in 1921 the 
injury done by the few beetles present was negligible. The reduction of 
this infestation was aided materially by the “tearing-out” during the 
winter of 1920-1921 of the more heavily infested sections in several 
houses, and incidentally by the collapse and subsequent rebuilding of 
the most severely infested house in February 1920. 
Treatment of a heavy infestation at Roelofs, Pennsylvania, was 
started in 1920. The “tearing-out” of some sections helped only 
partially in the control since some heavily infested beds were allowed to 
remain and the beetles from them spread to the new plants. A dust 
mixture made up of arsenate of lead 10 parts, and sulphur 90 parts, 
was applied regularly during the summer and autumn of 1920 and the 
spring of 1921. The infested houses w^ere fumigated once during the 
“drying-off” period in 1920 with hydrocyanic-acid gas at the rate of 2 
ounces sodium cyanid per 1,000 cubic feet of space. During September 
and October 1920 the beds were watered heavily and the surface of the 
pools and puddles filmed with kerosene nicotine oleate, 1 using 1 pint of 
stock solution to 4 gallons of water. This was found to kill all beetles 
which came in contact with it while struggling in the water. Only a 
few scattered beetles could be found in several examinations in 1921. 
Dusting was continued throughout 1921 and also 1922 as a precaution¬ 
ary measure, and the infestation during July and August 1922 was 
negligible. 
In a greenhouse at Oak Lane, Pennsylvania, 35,000 rose plants had 
suffered severe injury during 1919, 1920, and 1921. About two- 
thirds of the beds were replanted in the spring of 1921 but the infesta- 
*Dr. Wm. Moore, Jour. Econ. Ent., June 1918, Vol. II, no. 3, pp. 341-342. 
