-17- 
The Florida Agricultural Experiment Station (6l) in 1929 reported that on 
Asparagus plumosus Derrisol spray gave "better control of red spiders than 
did ordinary flowers of sulfur. 
Garlick (63) in 1929 reported experiments made in Ontario for 'the control 
of the red spider on raspberries and "black currants. Derrisol was tried at 
1:200 plus 1 pound of fish-oil soap per ko imperial gallons. This had 
practically no effect on the red spider. Finely powdered derris at the rate 
of 2 pounds per Uo gallons of watpr plus 1 pound of soap gave some' results, 
hut the mites very soon came hack. The. derris left on the leaves apparently 
had no toxic effect on the mites. Often the mites actually preferred parts 
of the leaf where particles of derris were thickest. Eggs laid under such 
conditions hatched normally, and the immature forms were able to develop. 
This was true even when the dry derris particles were. so thick as almost to 
obscure the leaf tissue. The fish-oil soap was used as a spreader. In order 
to find out whether it had any effect on the spiders, a -spray composed of 5 
pounds .of the soap in ho gallons of water was tried. It had little or no 
effect on the mites. 
According to an anonymous writer (l) in 1930, the milky colloidal solution 
of resins and other compounds obtained by extracting the roots and stems of 
Derris elliptica with water has been found effective against red spiders. 
The powdered, material may be applied as a dust with equal effect. 
Compton (^3) i n 1930 recommended Derrisol for the control of the red spider 
on acacia, achyranthes, ageratum, alternanthera, cineraria, gerbera, hydrangea, 
lace flawer, lantana, larkspur, lupine, petunia, primrose, rose, salvia, and 
schizanthus- in greenhouses. Compton stated that Derrisol may be used with 
safety on all greenhouse plants at the dilutions recommended by the'manu- "tur 
facturers. 
Davidson (^l) in 1930 reported the results of spraying and dusting tests 
with rotenone on a variety of insects. Pure rotenone, recrystallized from 
alcohol, was tested in the form of ^1) suspensions produced by adding an 
acetone solution of rotenone to water, and (2) diatomaceous-eari.h powders 
containing 1 or 2 percent of very finely divided rotenone. Aqueous suspensions 
were not effective against red spiders on beans. This inefficiency against 
the red spider appeared, to be due more to lack of penetrating power in the 
suspensions used than to absence of intrinsic toxicity, and would probably be 
remedied by incorporating rotenone in a penetrating carrier, such as an oil. 
.of rotenone 
The contact insecticidal act ion /on active red spiders on beans growing 
in a greenhouse, applied as a .suspension in water, was as follows: 
Concentration (gm. /.cc. ) Net mortality (percent ) 
1:90 73.6 
1:1,000 6U.5 
1:2,000 60.7 
1:20000 "-SxbJSSSboabd 
