The pyrethrum plot had 22.6 percent and the derris plot 5,5 peycent of 
the berries infested. 
Pether"bridge and Thomas ( 316 ) in 1933 reported that in I93I a 
good control of the raspberry "beetle in England had been obtained with 
a proprietary preparation of soft soap and powdered derris used at the 
rate of 1 pound of derris to 60 imperial gallons of water. This was 
applied when the eggs began to hatch and again h days later. In I932 
a derris powder (2.2 percent of roteno .e) at the rate of 1 pound in 
50 imperial gallons of water, plus a proprietary spreader for the first 
application and 5 pounds of soft soap for the second, was used in the 
Isle of Ely. The percentage of dsunaged raspberries from this plot was 
^,9, as compared with k.S from the plot sprayed with soft soap, 5 pounds, 
and nicotine sulfate, 10 ounces, in kO imDrrial gallons of water, aftd 
SU.S percent from the unsprayed plot. In Essex in the same year tw« 
sprayings with soft soap and derris powder gave satisfactory control of 
the raspberry beetle. Foar sprayings gave still greater control, but 
not sufficient to make more than two spray'.ngs an economic proposition. 
On Ifiganberries tv;o sprayings of soft soap and derris with a power sprnyer 
gave R fairly good control (13.3 percent damaged berries) of this beetle. 
Two dustings with a derris dust gave a better control (U.5 percent damaged 
berries) than two sprayings (I3 percent damaged berries). The authors 
conclude^d that dusting with a derris dust (containing 0,2 prrcent of 
rftenone) is the most satisfactory means knovm at resent of reducing 
the damage done to loganberries by the raspberry beetle, 
Spron (35^) iJ^ ^933 reported that an aqueous suspension of pure 
rotenone gave excellent results. 
Steer (358) in 1933 reported further experiments on the control 
• f B, tomentosus . Tests were mar'.e with a very finely ground derris 
powder containing 5«S7 percent of rotenone. The sprays were made t# 
contain 13-3/^ ounces of this pox^rder per 100 imperial gallena (rett^none 
content 0*005 percent) or double this strength. The dust vras composed 
of 1.6 percent of this derris powder and 9S.U percent of china claj'', 
making a roteno:re content of 0.09 "oercent. Three applications of a 
derris dust, about 100 pounds per acre, reduced the infestation p-^r 100 
berries from 75.5 to 12,5. Tv;» sprayings v/ith derris pov/der (rotenone 
content of spray = 0.01 percent) plus soft soap, 5 pounds p'-r 100 imperial 
gallons, reduced the infestation per IfO berries from 78, S to 0.^. A 
proprietary derris and soap preparation used with success in previous 
seasons reduced tlie infestation tr 0,9. According to Steer, an estimation 
of the rotenone content appears to be the most satisfactory method cf 
assessing the value ef a sample of derris, and such estimations have been 
used as a means of standardization in the trials described. Steer oon- 
cludod that a spray containing sufficient finely ground derris to givo 
a roten-^ne content of 0,005 percent, and 5 pounds of soft soap per 100 
gallons, gave excellent results against larvae on both raspberries and 
loganberries, whether used according to the double-spraying or the new 
single-spraying method. Besides reducing the percentage of fruits in- 
fested, it had an enormous beneficial effect on the yield and quality 
^f the cr'>p. A derris dust containing 0,09 percent of rotenone again 
gave a serviceable measure of control on raspberries but was somewhat 
inferior to any of the vrct sprays used. Preliminary trials shov/od that 
the pest can be controlled pn cultivated varietites of blackberries by 
means of derris. 
