-158-." 
Steer ( 594 ) in 1936 published a sunr.ia.ry of the use of derris as an 
insecticide in England. Promising results were obtained in 1934 with 
derris and soap against larvae of the apple tortrix. 
This pest on carnations was .killed by a product containing 12 per- 
cent of powdered Lone hoc ar pus nicou root (6 percent rotenone content) and 
88 percent of talcum, according to Etablisserrents Rotenia ir. a letter to 
R. C. Roark in 1938. 
Zygaenidae 
Artona catoxantha ( Kmps . ) 
Van der Vecht (454) of Buitenzorg, Java, in 1936 reported that the 
well-known coconut pest (Bracrartona) Ar to no. cat o xantha was readily killed 
in the laboratory by dusts containing from 0.5 to 1.0 percent of rotenone. 
In the field a derris dust containing 1 part' of ground derris (11 percent 
rotenone) and 10 parts of talc, and applied by a motor duster, conpared 
favorably with the pyrethrum product "Dusturan". In another field experi- 
ment derris dusts containing 0.5 percent or 1.0 percent of rotenone killed 
about 90 percent of the caterpillars. In 1935 van der Vecht ( l-55) reported 
that the addition of 1 to 2 percent of talc to spray suspensions used 
against this species helped to fix the particles of derris on the smooth 
lower surface cf coconut leaves and also served to indicate the thorough- 
ness of application of the spray. In 1939 van der Vecht ( 456 ) reported 
that laboratory experiments showed that aqueous suspensions of derris pow- 
der containing 0,005 percent of rotenone caused a 100-percent kill of 
fourth instars, whereas a total mortality of full-grown larvae was ob- 
tained after spraying with suspensions containing 0.01 percent of rote- 
none. Furthermore, it was observed that the residue cf the suspensions 
kept Its toxicity to Artcna larvae for a considerable period, especially 
when talc was added, which apparently improved the sticking power of the 
derris and rendered the residue more easily visible. In field experiments 
in West Java 2 infested localities with 800 and 4,O0Otrees, respectiv 
were sprayed with derris- and cube-talc suspensions, containing 0.015 to 
0.03 percent of rotenone; in both localities large numbers of o illars 
were killed and in the next generation the remains of the populat ; re 
destroyed by parasites. From the results experiments, it may be 
ccncluded that spraying with derris-talc suspensions : re effective and 
cheaper than dusting, and that the various difficu] bed with the 
latter method can be avoided by the use of s of 
sprayr.ii, over dusting are that the treatment of the highest 1 
no special difficulties, the disturb', ct of str Lnda is r.uch 
less pronounced, the sprayers ^-ansported, and the work 
can be better controlled. For these reai 
applied in- a number of outbreaks in central Java in 1938. 
Harrisin a a mc r i c a na ( Gue r . ) , the leaf skeletoniz r 
Dickoy and Loucks (98) in 1938 recommended derris for control 
in Florida. 
