. -137- 
Derris is ineffective against this insect. — Huts on ( 208 , 209 ) in 1936 
and 1937. 
The United States Department of Agriculture on January 13, 1936, pub- 
lished a press release which called attention to certain disadvantages that 
bar the use of rotenone insecticides for some typos of insects, Derris is 
not effective against all insects, e.g., the celery leaf tier. 
Howard and Mason ( 196 ) in 1937 reported that derris or cube was in- 
effective against this insect. 
The Massachusetts Agricultural Experiment Station ( 270 ) in 1937 re- 
ported that derris and pyrethrum were tested for control of the greenhouse 
leaf tier on snapdragons in two separate experiments on greenhouse grown 
plants. Commercial pyrethrum sprays diluted 1:200 and 1:400 and applied 
at approximately 10-day intervals gave good control. A derris extract con- 
taining 1.5/ percent of rotenone was also satisfactory. Derris-powder washes 
(2 lb. and 3 lb. in 50 gal.) permitted 66 percent of moderate or severe in- 
jury and were surprisingly unsatisfactory. Derris and pyrethrum clay dust 
diluted with inert clay were less effective than the liquid spray and left 
a very objectionable residue on the plants, T/hich generally eliminates 
these dusts from commercial use on snapdragons. 
.Parks and- Pierstorff ( 324 ) in 1938 wrote as follows: "Apply two pyre- 
thrum or rotenone sprays within 30 minutes. The first brings them out of 
heart leaves and the second kills them." 
Pionea forficalis (L.) 
Miles ( 277 ) in 1931 wrote on the garden pebble moth, which is a pest 
of cabbage, cauliflov/er, and allied cruciferous plants in England. A spray 
can be used for controlling the larvae of the pest in plants so long as the 
center or heart of the plant is loose and open; soap and nicotine spray or 
a spray containing derris extract, forced well into the plants and played 
on the undersurfaces of the l©avos, should be satisfactory. 
Pyrausta aurata meridional is (Stgr. ) 
Bremond and Rungs (49) in 1938 reported that in Morocco experiments 
using sweetened-bait traps gave poor results. A commercial insecticide 
containing rotenone 3 percent, powdered soap 67 percent, and inert matter 
30 percent, applied as a 2-percent spray 4 days after the beginning of 
adult flight and again 8 days later, gave good control. Equally good re- 
sults were obtained with a commercial rotenone-containing dust. 
Pyrausta nubilalis (Hbn. ), the European corn borer 
Worthley ( 501 ) in 1929 reported that derris powder was ineffective 
against eggs of the European corn borer laid on potted corn plants, but 
would be given further trial as a larvicide. 
