- 66 - 
times to peanut vines increased the yield of peanuts 44.4 percent and 
was superior to bordeaux and pyrethrum- sulfur dusts. On alfalfa the 
tests wore not conclusive because of dry weather, but the rotenone-sul "ur 
dust was inferior to the pyrethrum- sulfur dust. The treated alfalfa was 
greener fan the untreated. 
Sleesman (243) nve the following data on the relative populations 
of leafhopper nymphs en potatoes receiving various spray ana dust treat- 
ments at hcGuffey, Chic, in 1935. The numbers given are average! 
replications. 
1 lve 
Treatment 
Leaf hopp er ny mphs 
lumber 
Sulfur-lime 90:10 6 
Sulfur-derris (0,024 percent ro ten one) 13 
Sulfur-pyre rhrum (0,05 percent pyrethrin) 8 
Sulfur-pyre thrum ( 0.0125 percent pyrethrin) 11 
Sulfur-pyre thrum (0.00625 percent pyrethrin) 10 
Bordeaux 4-6-50 6 
Bordeaux 8-4-50 8 
Bordeaux 12-4-50 10 
Copper-lime dust 20;80 20 
Un sprayed 81 
Smith (244) in 1937 reported that derris powder (4 percent rotenone 
at 2 pounds per 100 gallons of water -lus about 2 pounds (dry-basis of 
coconut-oil soap reduced the leafhopper population on beans 94 percent 72 
hours after spraying. 
Turner ( 274 ) in 1937 reported that a derris-clay dust (rotenone 
0.6 percent) y/a£ not effective against the potato leafhopper on dahlias. 
Eoward (149) reported that in 1932 sulfur and sulfur-pyrethrum dust 
gavp the best control oi the potato leafhopper on beans in Ohio. Derris 
sprays were comparatively ineffective, ".hen used with peanut oil or pine 
oil the effectiveness of the derris sprays was increas'ed, hut peanut oil 
caused a yellowing of the bean ? eaves and subsequent defoliation and, 
although pine oil caused less ir.i\iry to bhe bean foliage, it appeared to 
be too injurious to he recommended for cenersl use. 
Sla.pta.son (242) in 1958 recorded some comparisons of dusts for 
potato leafhopper control en Long Island, when the insects were unusually 
abundant, The dusts were applied at the rate of 3 5 pounds per acre per 
applicat ion with an 8-rov Messenger duster mounted on the draw bar of an 
Oliver tractor and operated by a power take-off. The Cobbler variety* -wa^j 
dusted five times and the Green fountains six times during the growing 
season. All the materials used were prepared in a Bean self-mining 
duster just prior to each application. Two preparations contained rotenor 
(l) A mixture of 15 pounds of root of 5 percent rotenone contert vdth 85 
pounds oi Bancroft clay, and (2; a mixture cf 10 pounds of pyrethrum, 15 
pounds of rotenone-bearin. 5 root, 37.5 pounds of Bancroft clay, and 37.5 
pounds' of dusting sulfur. On cobblers, rotenone was rather ineffective 
he plants receiving this treatment 
in the control ef leafhopj ers, an 
about 4 or 5 days after the check vine 
showed 100-percent hopperfcurn. 
at which time they also 
