-53- 
A wettable powder containing 25 percent of DDT (4 pounds per 100 
gallons of -water), applied at the rate of 125 gallons per acre, was 
more effeotive in controlling inseots and increasing yield than Bordeaux 
8-12-100* The addition of 4 pounds of Fermate or Grass elli CAC still 
further eohanoed the yield.— Gui (192) ♦ 
Significant reductions an potatoes in Nebraska were obtained with 
a 3-peroent DDT dust and a 10-peroant DDT 8 pray 4 pounds per 100 gallons 
of water* In another experiment replicated plots of potatoes whioh were 
heavily infested with potato leafhoppers were treated three times with 
a 1 percent DDT dust at approximately 2-week intervals* Within 12 hours 
after the first treatment leafhopper populations were reduced to a 
relatively insignificant level and this oondition was maintained for 2 
weeks even in the presenoe of frequent heavy rains. Foliage on the treat* 
ed plants remained green and the plants matured at the normal time, where- 
as foliage on the untreated plants was almost all dead 2 weeks earlier* 
An inorease in yield of approximately 265 peroent was obtained* Field 
plots of beans heavily infested with potato leafhoppers were treated on 
June 19 with 1 or 3 peroent DDT dusts. Nymphal population records were 
taken four times during the next 17 days. After 12 hours leafhopper 
nymphs were reduced to a very low and apparently insignificant level by 
both the 1 peroent and 3 percent dusts. Although the difference between 
the two dusts was not statistically significant, apparently the 3 per- 
cent dust was slightly better*— Tate et ^al* (342 ) » 
In small-plot experiments, 3-percent DDT dust gave good control of 
the nymphs and yielded 115 bushels of potatoes per acre, while 4-4-50 
bordeaux plus 2 pounds of calcium arsenate yielded 98 bushels.— Apple 
(75). 
In a field test an beans 8 ounces of TOT per 100 imperial gallons 
of water gave complete control as a powder suspension and in Velsiool 
♦Mulsion. Apparently newly hatched nymphs were killed as well as tha 
older nymphs and adults*— Ross (306) * 
At Jefferson, N* C*, plots treated with a 3-peroent DDT dust for 
the control of flea beetles and leafhoppers yielded more potatoes than 
did any of five other differently treated plots*— Kiilash (240 ) » 
Laboratory tests with a 3-peroent DDT dust gave 96 peroent oontrol 
in 3 hours*— Okla* Agr* Expt* Sta* (IT8 )* 
A 5-peroent DDT dust gave exoellent oontrol of the potato leafhopper 
on potatoes .—Hut son (220 ) • 
DDT furnishes one of the best examples of the need of proper spac- 
ing between plots when spraying or dusting and the influenoe of drift- 
ing materials on adjacent plots* The drift of small amounts of DDT into 
plots during applications and the carry-over of the same material on the 
