- y- - 
a decrease in aphid, infestation in plots that had an initial infestation 
and an increase in yield of peas ranging from 123.3 to ^O^-.O percent 
over the unsprayed plots. The highest yields, however, had no initial 
infestation. 
Graham (130 ) in 1937 reported that in 1932 Pyrote (a pyrethrum- 
rotenone product) , 1 gallon to U00 gallons of spray, gave an 89-72 per- 
cent kill of pea aphids in Maryland. In 1935 in the same field where 
the nicotine and soap tests were conducted, plots of the same size were 
laid out and a 3 percent rotenone-derris dust, without a spreader, at the 
rate of k pounds per 100 gallons of spray, was applied at the same time 
as the above-mentioned nicotine spray. Records were made on yield and 
aphid infestation. The results showed a slight decrease in aphid infes- 
tation and no increase in yield of peas over the check plot. 
In 1936 derris plus sodium lauryl sulfate was tested. Plot 5 re- 
ceived one application of derris dust containing 0.75 percent of rotenone 
at the rate of 10 pounds plus 1/2 pound of sodium lauryl sulfate spreader 
to 100 gallons of spray at the "beginning of the "blooming period. This 
plot produced lh2 pounds of shelled peas per acre, an increase of 128.3 
percent over the check. The aphid infestation "before the peas were 
sprayed was 15 per tip "but 2k hours after the peas were sprayed it was 
only 2 per tip. 
Plot 7 received one application of derris dust containing rotenone 
at the rate of 6 pounds (active derris extractive material, including 
rotenone, 8 percent) plus 1/2 pound of sodium lauryl sulfate spreader 
per 100 gallons of spray. This application was applied 10 days before 
the peas "began to "bloom, and produced 1,128 pounds of shelled peas per 
acre, an increase of 2H7 percent over the check plot, llo aphids were 
present when the spray was applied but 12 days later the infestation 
averaged 0,5 aphid per tip. 
Plot 8 received two applications of a similar derris dust, the 
first 10 days before blooming started, the second when the peas "began 
to bloom. The yield in shelled peas per acre was 1,63s pounds, or an 
increase of kok percent over the check. !"o aphids were present before 
the first application nor 2 days after the second. 
Plot 9 received one application of derris containing rotenone, 
the same strength and spreader as in Plots 7 and 8. Application was 
made when the peas first came into bloom. The yield in shelled peas 
per acre was 817 pounds, or 151.3 percent increase over the check. The 
aphid infestation just before the spray was applied was lU per tip, but 
2k hours after the application it was 7 per tip. 
At harvest time the rotenone-treatcd plots were green and succu- 
lent and the pods well formed and tender; whereas check plots and nicotine- 
sulfate-treated plots were practically dead and the pods poorly developed. 
Another index to the efficiency of derris dust containing rotenone over 
nicotine sulfate was the number of aphids on the ground after harvest. 
Under the derris- rotenone- sprayed plots only an occasional aphid could 
be found on the plot that received two applications, and a few more on 
the plots that received one application, whereas under the nicotine- 
