-115- 
One of the more important uses of rotenone is to control the 
iris thrips. The following spray mixture was found effective 
against thrips (except the gladiolus thrips) on certain flowering 
plants: 
For small For large 
quantities quantities 
Rotenone-containing root 
powder (4 percent of rote- 
none) 1 tablespoon- 
ful 1 pound 
Alcoholic extract of pyre- 
thrum (2 peroent of pyre- 
thrins) 4 teaspoon- 
fuls 2 quarts 
Sulfonated caster oil 
Hater 
2 teaspoon- 
fuls 1 quart 
1 gallon 50 gallons 
—Howard and coworkers (294, p. 31) • 
Diarthrothripg ooffeae Will*, a coffee thrips 
In Tanganyika a spray of Derrisol in water or bordeaux mixture 
(1:500) was effective and was cheaper than nicotine sulfate*— Notley 
(447). 
Frankliniella cephalica (Crawf*), a strawberry thrips 
The control for this thrips (F* cephalica bispinosa Morgan) is 
a derris spray containing low concentrations (0*015:0*02 percent) of 
rotenone.— Smith (555) * 
Frankliniella fusoa (Hinds) , the tobacco thrips 
Experiments with dusts and sprays of cube and pyrethrum were con- 
ducted on shade-grown tobacco in Connecticut* Pyrethrum dust was the 
only treatment that gave significant results* On the sun-grown to- 
bacoo, pyrethrum dust was also more effective than cube dust, and the 
latter was more effective when it contained no wetting agent* In later 
tests pyrethrum dust gave better control than did any of -the other 
treatments, except that it was not significantly better than the treat- 
ment in which pyrethrum was alternated with cube* A cube-tobacoo 
