- 543 - 
HEADLEE, l 1 . J. (2300) 
1923. TEE MAINTENANCE CF A SPRAY COATING ON FRUIT AND FOLIAGE OF APPLI 
AS A MEANS OF CONTROLLING CURCULIO AND CODLING 1/iOTH miERE THE LATTER 
IS PARTICULARLY ABUNDANT AND THE PRESENT STATUS OF NICOTINE DUSTS. 
Peninsula Hort. Soc. [Del.] Trans. 36: 15-21. 1922. illus. 
The value of nicotine dust is not measured "by the amount of nicotin 
which it contains, "but "by the number of pounds of nicotine which it 
will deliver under the conditions under which it must "be used. 
HEADLEE, I. J., end RUDOLFS, Y7. (2301) 
1923. SOkE PRINCIPLES T7HICH UNDERLIE THE MAKING AND USE OF NICOTINE 
DUST. N. J. Agr. Expt. Sta. Ball. 381, 47 pp., illus. [Abstract in 
Rev. Appl. Ent. (A) 12: 31-33. 1924.] 
Dolomite and hydrated lime with 10 to 30 percent dolomite are 
the "best carriers for nicotine sulphate. 
Field experiments with Acyrtho sipho n ( tv.acrosiphum ) pisi indicate 
that a minimum of 50 pounds of 1.5 percent frue nicotine dolomite 
dust should "be used for 1 acre of infested peas where these are 
planted in solid rows 40 inches apart. Against M. solanif olii at 
• least 30 lb. of this dust per acre should be applied. No satisfactory 
results were obtained with the dust against Thrips t abac i (onion 
thrips) and it was also relatively inefficient against Myzus persicae 
(peach aphids) on pepper plants. 
PARROT! , P. J., and MACLEOD, G. F. (2302) 
1923. TOBACCO DUST AS A CONTACT INSECTICIDE. Jour. Scon. Ent. 16: 
424-430. [Abstract in Rev. Appl. Ent. (A) 11: 582-583. 1923.] 
Tests were made to determine the effectiveness of tobacco dust 
against the aphid Myzus persicae Sulz. on Cnryopteris mas t acanthu s 
in a greenhouse. Finely ground (200-mesh) tobacco is more effective 
than coarsely ground (50-mesh). Hydrated lime in combination with 
tobacco dust promotes the liberation of nicotine and improves tne 
physical condition of the dust but in general such mixtures have 
decreased toxicity. Tobacco dust alone was somewhat less toxic than 
mixtures containing free nicotine or nicotine sulphate. Free nico- 
tine dust was more rapid in its paralyzing effect than dusts con- 
taining nicotine sulphate, and tobacco dust was the least rapid in 
dislodging the insects. Mixtures in which kaolin was incorporated as 
a carrier of free nicotine or nicotine sulphate showed less than 80 
percent killing efficiency, while the preparations using sulphur and 
calcium carbonate or hydrated lime as carriers of the nicotine 
were decisively more efficient. 
