-31- 
pear orchards in Shizuoka, Japan, had become scree, probably owing to 
the use of insecticides, including, derris. 
Parasa herbifera (Walk.) 
Gater ( 15 A ) in 1925 reported dipping tests with nature larvae of 
this species to determine the relative values of extracts of different 
species of derris. 
Setora nitens ''Valk, 
Van der Scheer (360 ) in 1935 ascribed the unsatisfactory results 
reported for the use of rotencne suspensions to a lack oi stability of 
the suspensions used, and suggested first dissolving the ro'tenone in 
a liquid insoluble in water, then preparing a rotenone emulsion from 
this solution, because emulsions are regarded as being more stable 
than suspensions. Benzene is well suited as a solvent for rotenone 
for the preparation of rotenone emulsions. Soap is not suitabl , 
because of its alkaline reaction. Igepon T may be used, is follows: 
One gm. of rotenone is dissolved in 20 cc. of benzene, "his is added 
to 30 cc. of Igepon T solution (0.3 to 0.5 percent Igepon T) and the 
mixture agitated until a homogeneous liquid is obtained, This concen- 
trated emulsion is then diluted with water to the desired concentra- 
tion, which should first be determined on a small scale- The spray 
material must be kept in a closed container, or evaporation of the 
benzene will cause the rotenone- to separate from the emulsion. This 
disadvantage may be avoided by the use of so: xpensive essential 
oil, such as "katjang" oil, which also has some insecticidal activity, 
and which protects rotenone from oxidatior. Stable emulsions were 
prepared by the addition of pine oil to the katjang oil. Oil eit- 
ronella may also be added. The rotenone-benzol emulsions at a concen- 
tration of 1:5,000 gave good control of "Se tora nitensis ." The fruit 
of the lerak ( Sapindus rarak ) contains a saponin that is an excellent 
emulsifying agent and may be used to replace the Igepon T. By he* t- 
ing 8 of the fruits with 1 liter of water, sufficient emulsifyi 
agent to prepare 250 liters of emulsion is obtained. 
Limacodidae (unidentified sp.) 
■« 
The Ceylon Tea Research Institute (66) in 1930 describ d tests 
of insecticides against net 4 "! grubs on tea in Ceylon. Nicotine oleate 
at the dilution tested gave ve~y disappointing results, • v sol- 
ution made from the fgl^age of Tephrosia vogelii waseffectiv . 
Lyman triid 
Arctornis alba (Bremer) 
Sonan ( 378 ) in 1927 reported that sprayii lerris nnd soap 
proved very effective against this'species Infestii \ tea plants in 
Formosa . 
Dasychira mendosa (Kbn.) 
Sonan ( 378 ) in 1927 reports! that spraying witl derris \ rid so^p 
