■33- 
The follo^ina: results were obtained in 1932: 
Rotenone concen- 
tration 
Insect 
Host 
RpSUlt 
Locality 
Is 5,000 
Spider 
1:2,500 
do. 
1:5,000 
do 
1:2,500 
do* 
1:5,000 
do. 
1 : 2 , 500 
do' 
2 percent 4-1 
percent 
soap 
do 
Do. 
do ., 
Rose No result 
do do 
Grape and pear do 
do . do . 
do. 
do. do 
Aalsmeer 
Do. 
Naaldwijk 
Do. 
Unsatisfactory Goes 
i 
Do. 
Stringbeen Satisfactory Amsterdam 
Cucumber do. Do. 
1 percent-^ 1 percent 
of soap 
do :. 
do' 
Not satisfactory Do. 
In 1934 the Wageningen Plantenziektenkundige Dienst ( 155 ) reported tests 
T-rith rotenone and derris. Rotenone, with the addition of 0.1 percent of Agral 
I, was sprayed with the following results: At Amsterdam this material at the 
rate of 1:5,000 was satisfactory against mites on pears and mites on grapes; 
1:5,000 was satisfactory against mites on pears and mites on grapes; 1:5,000 
kills the mites but not the eggs, therefore repeated spraying is neeessary. 
Rotenone, without the addition of Agral I, seve results as follows: At 
Pancras 1:10,000 against mites on grapes killed abput 70 percent of the mites; 
at Naaldwijk 1:2,500 on nonbearins: pears was satisfactory for control of mites 
at Eoskoop 1:5,000 did not give satisfactory control of mites in cucumlers, 
when sprayed during the day on May 27; enH 1:5,000 0.1 peroent of Agral I, 
sprayed during the da ir on June 6, was also unsatisfactory. TThen used at a 
concentration of 1:10,000 with 0.1 percent of Agral I, however, and sprayed 
in the evening on July 19, no living mites coul^ be found on July 20. The 
same plot was sprayed in the evening regularly each reek with rotenone 
1:10,000 0.1 percent of Agral I. Cucumbers were harvested from this plot 
for 3 weeks longer than from the untreated plot, and commanded a higher price 
because they ^ere practically free fron insect injury. Alvesco derris dust 
did not give satisfactory results in the control of the " spint" (a mite) on 
grapes at Naaldwijk. 
DeEussy, Van der Laan, and Jacobi (19) in 1935 reported the results of 
tests with derris powder and rotenone on a number of insects in the Nether- 
lands. Thirty- t"-o species were found to be sensitive to dusting with derris 
