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arssnate treatment was injurious to the plants. Examination of the 
berries at harvest time showed no reduotion in infestation attribut- 
able to the derris.— Lathrop (366 , 367 ) . 
Rotenone is effective against blueberry and huckleberry inseotsj 
nicotine is ineffective.— liolndoo (383 ) • 
Effective control was observed on apple trees that had receiv- 
ed three applications of 0.6-percent rotenone dust.— German and 
Towns end (223 ) • 
In 1942 a dust of derris or cube powder (4 percent of rotenone), 
white lubricating oil, and pyrophyllite (13»4:8S) > , applied to apple 
trees five times at 10-day intervals, and a spray of -J pound of lead 
arsenate, 2.5 pounds of cube (6 percent of rotenone), and 1 quart of 
summer oil per 100 gallons of spray, applied four times at 10 to 12- 
day intervals, reduced the percent infestation to 0.16 to 0.27 and 
4.2 to 24.3, respectively, as compared with 20 to 30, and 90 to 100 
in 1941, when no treatment was given. It appears that both treatments 
gave considerable reduotion in the apple maggot infestation, with 
the dust treatment probably exceeding the spray in effectiveness.— 
Dean (137) . 
Promising results on apple trees were given by rotenone dusts 
in 1937. High temperature and high humidity had very little effect 
in reducing the mortality of oil-impregnated rotenone dusts in the 
laboratory, but exposure ,to strong sunlight destroyed the aotive prin- 
ciples of the dust in a few days. A dust containing 4 percent of 
white lubricating oil and enough derris to give 0.5 percent rotenone 
with aluminum silicate retained its effectiveness for 3 hours in bright 
sunlight in midsummer. When applied to trees it rapidly destroyed the 
flies at first but they reappeared in 4 to 5 days. When adult flies 
and artificial sunlight were used there were no significant differences 
in favor of stabilized derris or the dusts containing oil. Chemioal 
analyses showed, that rotenone was less rapidly destroyed when the 
carrier was red clay than when it was pyrophyllite. Field experiments 
with oil- impregnated derris dusts (0.6 percent of rotenone) showed 
that they were of value for late-season work. Five applications of 
an oil-impregnated dust of derris and pyrophyllite reduced the infes- 
tation of picked and dropped fruit to 7.2 and 25.9 percent, respec- 
tively, as compared with 87.5 percent for both together in untreat- 
ed plots. Rotenone dust, such as used in 1939 to 1941, enable one 
to extend the season of apple maggot oontrol much nearer harvest and 
to kill much more rapidly than with lead arsenate. Oil- impregnated 
rotenone dusts may have a place in late season control in order to 
avoid arsenical residues. Five applications of a 0.5 percent roto- 
none dust in an orchard in 1942 produced a fairly clean crop of fruit, 
