ag: ‘dg Se ta 
L. W. Brannon, Norfolk, Va:, reports thet in’ cooperation with a 
grower a traction duster was used in an experiment in which several 
rotenone-content dusts were used against the harlequin bug. Very poor 
results were obtained with the traction duster, even enoued the nozzles 
were arranged in several different ways. Best results were obtained 
when heavy applications were made with a hand duster. Counts indicated 
that a commercial derris dust at the rate of 38 pounds per acre had a 
repellent action. Practically no kill was obtained with rotenone-con- 
tent sprays 1-200 in an experiment made when the temperature was 68° F. ~ 
and the relative humidity 76 percent. The same materials gave excellent 
resuits when the temperature was 83° F. and the relative humidity 84 per- 
3 
W. J. Reid, at Charle ston, 5. C., reports that derris dust, mixed 
with tobacce dust to give 4 1.5 percent rotenone content, is particularly 
‘fective against the melon worn (Diaphania hyalinata lL.) and the pickle 
worm (Diaphania nitidelis Stoll ). In a series of plots in which derris, 
eryolite, ; yrethrua, paris green, lead arsenate, and calcium arsenate j 
were used, effective control was obtained in the orcer given. The derris 
plot procuced 765.5 pounds of Rabe fruit, as compared with 86.5 pounds © 
sound fruit produced on the calcium arsenate plot. The derris plot 
produced over 100 pounds more sound fruit than did the ecryolite plot, 
1 
which was next in effectiveness. The check plot produced no sound fruit. 
J. U. Gilmore, Clarkesville, Tenn., as a result of a series of tests 
on tobacco for the control of thé tobacco hornworm, states that neither: 
gyretirum nor derris, even at the heaviest doses, vave satisfactory horn- 
porn Bice shec: It is worthy of menticn, however , thet hornworm larvae, 
a feeding on derris, stopped meoeieE for a period, even ee sh they 
were eRe killed. 
CG. B. Wisecup, Sanford, Fla., reports that in the one feeding test 
conducted during October against the larvae of the southern armywornm, 
“alt and large larvae were introduced into cages with the following 
rotenone-containing dusts or sprays on sweet potatc leaves: 
Derris spray ~ 5 percent rotenone + 1 part in 200 
Derris dust -'3 percent rotenone,O.3 mg. per scuare inch 
proprietary cube extract - 1.6 percent rotenone - 1 part in 200 
Proprietary cube dust - 0.57 percent rotenone, 0.3 mg. per square inch 
The derris, with the greater rotenone: content, appeared somewhat more 
epellent, showing less feeding at the end of 2 days, when all larvae were 
renoved to fresh, untreated food. The’end results after a week's time 
perk, Sebpointing, aS no material had given a kill of over 33 percent. 
however, the derris gave consistently better kills, beth as dust and spray, 
indicating ‘chat the rotenone’ content must be taken into ‘aéeount when ‘recom- 
meniing a derris or cube product. 
