■-^109 - ■ 
Poplllia ,1a.p,onica Hevmi. , the 'Japanese "beetle 
The United States Dcipa.r't'mont of Agric'ilture, Bureau of Entoraology 
( j\Eh ) in 1929 stated that in testp against the Japanrso beetle derris was 
most effective when cxtra.cfed with coal-tar naphtha or ethyl alcohol. 
Extracts of pyrethrum and of' derris were atoxit eoua.lly effective. 
Davidson (^) in 193® reported- the following results with suspensions 
of rotenone in water against adults on smartvrced foliage in screen cages: 
Concentration 
Mortality 
G-rams: cc. 
Percent 
• 1:1,000 ■ 
100 
1:5,000 
97.3 
1:7,500 
gg.e; 
1:10,000 
85.2 
1:15,000 
g6.i 
1:20,000 
60.9 
Richmond ( 325 ) in 1931 reportr-d on the relative attractiveness or 
repellency of certain materials to the Japanese "beetle. A 5-pt"rcent solu- 
tion of Derrisine was mildly repellent to the Japanese "beetle in field tests 
in Few Jersey in 1925 and I926. A footnote at the end of the raper statrs: 
Since this paper was prepared, all the ma,teri^ls listed as 
mild repellents and as repellents have "been retested, and it is 
"believed thr,t none can be considered as practical repellents for 
the Japanese beetle. 
Metzgcr and Grant (28^) in IQ32 reported tests of U7U extracts 
representing 3*^0 plant species taken from 326 genera and 108 families, 
as repellents to th'- Japan.es beetle. Benzene, 95-pc'rcent alcohol, and 
^7»5-pprcfnt-alcohol extracts of the dry roots of dcrris (stat'^d to be 
Derris malaccensis Benth.). applied at dilutions of 1:25, l!35, 1»50, and 
1:100 (ratios of dry plant material to spra^y fluiJ in kg.: liters) were 
incffcct?-"' in repelling these beetles. The process of the United States 
Pharmacopoeia (lOth cd.) for preparing fluid extr'^cts v^-^s followed in making 
extr'-cts of these plants. Commercial derris ^nd pyrethrum povrdrrs used at 
the rat(. of 6 pounds to 100 gallons of water v/ere more repellent than were 
11 of the more promis^'ng plant extract <=. An extract of the whole plant of 
Tephrosia virginiana L. in flower in U7. 5-percent alcohol ^t a dilution of 
1:25 was ineffective. 
Gnadinger (165 ) in 19"^."'. referred to unpublished work by Ginsburg 
which indicates that the pyret'^rins arc more toxic than rotenone to the 
Japan e s e b «' e 1 1 e , 
The toxicit:' of rotenone and derris as contact insecticides to th- 
Japanese beetle is increa„sed by the addition of soaps. — United States De- 
partment of Agriculture, Bureau of Entomolog,v (386) in 1°"^3. 
