-107- 
orchard showed 50.40 percent oodling moth injury at harvest. An im- 
perfectly sprayed lead arsenate check plot showed 66.47 percent in- 
jury. On Hubbard8on, the DDT-oil plot had 48.63 percent, and the 
lead arsenate check plot 56.62 percent codling moth injury. In a 
well-sprayed and well-oared for Delicious orchard, four mid-season 
application.* of -the DDT-oil, followed by an oil-niootine schedule, 
produoed fruit shewing 2 percent oodling moth injury; the standard 
lead arsenate schedule, followed by oil-niootine sohedule, produoed 
fruit showing 3»3 peroent injury.— Cleveland (114 ). 
DDT at 1 or 2 pounds per 100 gallons of water proved to be the most 
outstanding of all materials used to control oodling moth at Hood River, 
Or eg. Moths are not particularly affected by the spray; also the spray 
failed to prevent hatching. — Childs and Robinson ( HI ) . 
In laboratory tests most newly hatched larvae were killed by 2 to 
4 ounoes of IDT per 100 imperial gallons of water applied suspension. 
DDT in other forms was less effective, although much more effective than 
lead arsenate. Mature larvae were very resistant to the contact action 
of DDT. DDT tested against adults at 5 pounds per 100 gallons was 
slightly less effective than sodium dinitro-cresylate*— Ross (306 ) . 
When used on a block of apple trees, DDT gave sensationally good 
control of the apple worms but killed off the small parasitic wasps, in- 
troduced 10 years ago to check the woolly aphids; freed of their natural 
enemies, the aphids increased immediately to dangerous numbers. --Bur tner 
(98). 
DDT used on the same schedule as lead arsenate, at the rate of 1 
pound of DDT to 100 gallons of spray, gave much better control of the 
codling moth. All experiments seemed to indicate that for excellent 
control, lead arsenate should be used early in the season and DDT later. 
—Hut son (220) • 
In a large-scale test at Vincennes, Ind., DDT was more effective 
than one of the best nicotine bentonite programs available, where the 
ratio of DDT to nicotine sulfate (40 percent) was approximately 1 pound 
per pint. At 1 pound per 100 gallons in small field-plot tests DDT 
gave muoh better control than the standard lead arsenate program (4 and 
3 pounds per 100 gallons). DDT is a very effective supplement or forti- 
fying agent when added in small quantities to lead arsenate or nicotine 
bentonite and can be used in split schedules ahead of or following sprays 
of lead arsenate, or nicotine bentonite* It can be used effectively 
with summer oils and with bordeaux mixture.— Steiner jrt al . (33 4 ) • 
The effectiveness of some compounds closely related to DDT and of 
their dehydrohalogenated derivatives against codling moth larvae when 
tested by the apple-plug method was determined. Each oompound was used 
