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over the kerosene, these would be instantly killed. I think that the 
same method would be effective in the strawberry fields as well, * 
unless this beating of the plants should interfere to some extent f 
with fertilization. 
Pyrethrum. As far as topical applications are concerned, I am 
able to report that we have in pyrethrum a perfectly effective J 
agent, which has at the same time the inestimable advantage, to 
the strawberry grower, of being wholly harmless to the plant and % | 
the consumer of the fruit. Recognizing the fact that ting 1 
was almost the only substance at all likely to prove useful H 
which it was permissible to apply to strawberries while m i 
fruit, I began to experiment with pyrethrum the first day of my i: 
visit to Southern Illinois, in May. Some plant bugs of all ages, i 
exposed in a vial to a little powdered pyrethrum,. began to show itsH 
effects in four minutes, by tumbling and sprawling about on their 
backs and sides, both old and young being equally disturbed. In , 
nine minutes some of the youngest were helpless and unable to i. 
walk, and in two more minutes nearly all but two were on their, 
backs, the youngest motionless, the others feebly struggling. . In two^ 
hours all were motionless or helpless, except one pupa, which var 
reviving. This last finally recovered and escaped, but the others all 
finally perished. 
Some additional experiments, made at the Laboratory this fall, 
were still more conclusive. Twenty-one adults were confined undffll 
a bell glass and dusted with a mixture of one part of powdered, 
pyrethrum to ten parts of Hour, at 8:10 A. M., November 5, and a. 
11:45 only two were active, the others being but feebly alive. AL 
1 -30 all were on their backs, showing signs of life only by a slow, 
action of their legs. In 24 hours three or four were feebly alive r 
and the remainder dead; white in 48 hours all were dead. 
Several trials were made with pyrethrum suspended in water, o.i 
which the following is a fair sample: Thirty-five adults wer« i 
sprinkled with water containing powdered pyrethrum in the ratio oj 
15 grains to the pint, at 11:05 A. M., November 8. At 12 M. nearl; 
all were lying on their backs, strongly affected; at 6:45. m thij 
evening, only eight were at all active, and the next morning bui, 
three were able to keep their feet. On the afternoon of the 9th, all 
were dead but four, and these succumbed during the night. 
Trial was next made of both the flour and the water mixtures} 
to test the supposition that the confinement of the insects had 
increased the efficiency of the pyrethrum in the above experiments 
Twenty of the bugs were thoroughly treated with water in whic. 
twenty grains of pyrethrum to the pint had been shaken up, anj 
the insects were then enclosed in a netting bag and exposed to thj 
air. In an hour all were helpless, the greater number being appai 
ently dead. Four hours after the treatment, five were feebly movin i 
their legs, but made no attempt to walk, the fifteen remaining bem, 
all apparently dead. In twenty-four hours all were dead but tw(| 
and these perished a few hours later. 
At the same time one part of pyrethrum powder was mixed witj 
ten parts flour, and sprinkled upon twenty adults which were the 
i 
