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most of 
or spray must hit the mites on the -under side of the leaves, where they do/ 
their feeding. If it is desired to control downy mildew, along with the bean 
beetle and the red spider, the rotenone spray should be combined with a 
copper spray. The 4 pounds of a 4-percent- rotenone ponder should be added 
to each 100 gallons of a bordeaux mixture or other copper spray, as advised 
for mildew control. A copper-rotenone spray should be applied soon after 
it is mixed. ' '...-* 
Hamilton (71) in 1939 recommended derris- or cube-extract sprays as 
contact poisons for the control of the red spider On house olents. 
According to % J. Haude, in advertising literature published by John 
Powell & Co., New York, N. Y. , in 1939, derris-oil sprays have been success- 
fully used for red spider control in the coastal areas; however, this use 
has not been extensive, except in areas where the black scale is also a factor. 
Sprays containing rotenone are effective for the control of the red spider on 
ornamentals. A contact spray containing the equivalent of 1 percent of 
rotenone may be diluted at the rate of 1 part to 400 parts of water. It is 
advisable that such a spray "hen diluted contain at least 0.5 percent of 
a nonalkaline retting agent. Busts are apparently not so effective as sprays. 
The addition of derris or cube to sulfur dusts "ill increase their efficiency 
against the red slider on cotton. 
O r Brien ( 115 ) .in 1940 wrote that, according to McDaniel of Michigan State 
College, red spiders dislike any preparation that contains derris or its 
derivative, rotenone. He recommends dusting with a copper-derris compound, 
which can be bought in commercial mixture, or spraying with a mixture of 
sulfonated' castor oil and derris powder. To 1 gallon of water, use a little 
less than a teblespoonful of the oil end a teespoonful of the derris. 
Brannon ( 15 ) in 1940 reported that a derris-pyrethrum-sulfur dust mixture 
is promising as an all-purpose dust mixture for the combined control of 
several species of insects commonly attacking beans, including the Mexican 
bean beetle, the bean leaf beetle, the potato leaf hopper, and the common red 
spider, and for the prevention of powdery mildew. 
Coleman and Lyle (42) in 1940 reported the results of tests with a large 
number of materials to determine the most effective and. economical control for 
red spiders, thrips, mealybugs, and aphids in greenhouses. The three most 
effective were Loro, Lethane, and derris extract. Derris extract diluted 
1:200 killed 98 percent of the red spiders, but it cost nearly 2.4 times as 
much as the same amount of Loro, which at 1:800 killed 97.8 percent of this 
insect. . . 
Morrison end Mote ( 110 ) in 1940 reported that a dust containing 0.75 
percent of rotenone plus 2 percent of sodium lauryl sulfate killed 35 percent 
of red spiders on hops in Oregon; whereas a dust containing 1 percent of 
dinitro-ortho-cyclohexylohenol killed 99 percent. Rotenone "as compatible 
with the proprietary DN dust (1 percent DN on "elnut-shell flour) but did not 
contribute added toxicity. 
