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Nettles ( 291 ) in 1939 recommended derris dust (0.75 percent rotenone) 
at the rate of 15 to 20 pounds per acre. 
Smith and Re id (374) in 1939 reported tests against the three common 
species of cabbage caterpillars, including the diamondback moth, using 
four insecticides, i.e., pyrethrum-talc (1:2); derris-dust mixtures con- 
taining 0,5 and 1.0 percent of rotenone, respectively; and a combination 
of derris -pyre thrum (0.5 percent rotenone and 0*2 percent total pyrethrins), 
applied at 7-, 10-, and 14— day intervals. The results indicated that py- 
rethrum was less effective than derris for control of diamondback moth. 
The combination of derris and pyrethrum was most satisfactory for the 
three species as a whole, and resulted in the best yields. Although dif- 
ferences could be detected between the 7-day and the 10-day applications, 
it was demonstrated that both were decidedly more effective than the 14- 
day applications. 
H. T. Pagden ( 522 ) in 1931 stated that neither derris sprays, with or 
without agral, nor pyrethrum sprays or dusts gave satisfactory control of 
Flutella on cabbages. Nicotine extract, 0,05 percent, gave better results. 
The New Zealand Department of Scientific and Industrial Research ( 505 ) 
in 1940 reported that tests at Owairaka showed that best control of this 
pest on cabbages was obtained with derris dusts, which proved to bo more 
efficient than nicotine sulfate spray or lead arsenate and calcium arsen- 
ate sprays. Arsenates when applied as dusts gave unsatisfactory results. 
Psychidae 
Clania ( Cryptothelea ) minuscula Butl. 
Yago ( 502 ) in 1933 wrote that this species, formerly abundant in pear 
orchards in Shizuoka, Japan, had become scarce, probably owing to the use 
of insecticides, including derris. 
Thyridopteryx ephemera eformis (Haw. ^, the bagworm 
Hamilton ( 180 ) in 1938 reported that in only one out of four tests 
were bagworms on evergreen trees satisfactorily controlled by a cube or 
derris spray (4 lb. of powder containing 4 percent rotenone plus 4 lb. of 
rosin-residue emulsion per 100 gal. of water). The spray acts' as a repel- 
lent. The period of effectiveness was 3 to 4 days. Bags do not fall off 
the trees, but larvae cease feeding and do not increase in size. 
Psychidae (unidentified sp. ) 
The Institute of Physical and Chemical Research ( 214 ) Tokyo, Japan, 
in 1927 reported that Neoton, 1 pound in 60 imperial gallons of water, 
warded off an attack by larvae of the pear bagworm for 7 days. Upon in- 
vading the field sprayod as above with Neoton, 20 percent of the larvae 
wero killod by the internal action of the drug. 
