- 543 - 
chiefly of sulphur and containing 3 percent nicotine killed only 61.7 
percent of the nymphs. Recommendations for nicotine sprays are given. 
MORRILL, A. IT." - . (2285) 
' 1921. NOTES OF THE USE OF NICOTINE DUSTS. Jour. Econ. Ent. 14 (5): 
394-400. [Abstract in Rev. Appl. Ent. (A) 10: 131-132. 1922.] 
"As a result of the conflicting reports -with regard to the 
effectiveness of r.icotine dusts against grape leaf hoppers ( Typhlocyba 
comes ) further experiments were undertaken, details of V7hich are 
described. In the dust tested, 7 l/2 percent and 10 percent of 
Black Leaf 40 were used, the analyses showing 2.4 percent and 3.8 
percent of nicotine respectively. In the former the carrier con- 
sisted of 90 percent hydrated lime and 10 percent sulphur, and in 
the latter about 75 percent sulphur and 25 percent lime. Ordinary 
nicotine dusts appear to "be of little value against the adults, hut 
stupefy the nymphs and cause them to drop. If there are no runners 
on the ground, and in the case of trellised vines, this is probably 
equivalent to killing them. 
"The results obtained against the melon-aphis (Aphis gossypii , 
Glov.) are similar to those recorded by Campbell (Rev. Appl. Ent. (A) 
9: 389). For scattered infestations the author advises dusts with not 
less than 7 1/2 percent Black Leaf 40. In the case of a general in- 
festation throughout the field it is advisable to use a dust con- 
taining only 4 or 5 percent Blrck Leaf 40. The importance of locating 
incipient colonies of aphids by scouting early in the season, is em- 
phasized. For cantaloupe plants the dust should not contain more 
than 10 percent sulphur to prevent scorching. 
"The dust does not apparently affect natural enemies such as 
Hj-ppodamia convergens and Syrphid larvae or the Hymenopterous para- 
site Aphidius testaceipes . 
"Contrary to the results obtained by Parrott (Rev. Appl. Ent. 
(A) 9: 352) colonies of the woolly apple aphis ( Eriosoma lanigerum ) 
were completely eradicated on small trees with dust blown from a 
distance of 3 or 4 feet with not enough air pressure to disarrange 
the waxy covering of the insects.- The dust remained attached to 
the wax, though it was hardly visible to the naked eye." 
OSBOEN, H. T. (2286) 
1921. A DUST INSECTICIDE AGAINST LEAFHOPPERS. Hawaiian Planters' Rec. 
2 5: 167-170. [Abstract in Rev. Appl. Ent. (A) 10: 29-30. 1922.] 
Nicotine dust is rather more effective than nicotine spray for 
the control of the sugarcane leaf hopper ( Perkinsiella saccharicida ) . 
The dust contained not less than 5.9 percent nicotine sulphate, 44 
percent inert carrier and 50 percent sulphur dust; this was applied 
by a hand duster. The spray used for comparison was 1 pt. nicotine 
sulphate to 1,000 pt. water with about 2 lb, whale-oil soap to every 
50 gal. water; an ordinary knapsack sprayer being used. 
