394 JOURNAL OF ECONOMIC ENTOMOLOGY [Vol. 14 



destructive numbers in many localities in California from Imperial 

 Valley to the central part of the state. In one instance at least it is 

 reported to have been successfully controlled by a 6% nicodust. 



Combinations of Nicodust 



There has also been collected a great deal of miscellaneous data on the 

 various combinations of sulfur, arsenic compounds and fungicides on 

 insect control. The use of lime instead of kaolin to produce a more 

 efficient dust by liberating pure nicotine to be further fortified by 

 the addition of dry sulfur at the time of mixing for nicosulfur dusts 

 appears from many experiments conducted under widely different con- 

 ditions upon various insects, to be more efficacious than nicodust of the 

 same strength without the sulfur. When sulfur alone is treated with 

 "Blackleaf 40" it appears to increase the efficiency of the nicotine over 

 lime alone, but because, of its weight it is not as easily handled in the 

 dusting machines as is the regular nicodust. 



Mixtures of nicodust and powdered arsenate of lead were very efficient 

 in controlling caterpillars and flea beetles, particularly the latter on 

 tomatoes. 



Dusting for the control of the codling moth has received a considerable 

 impetus and a large number of experiments are under way, mostly con- 

 ducted by orchardists or insecticide manufacturers. We are contem- 

 plating a definite series of experiments along this line next year. 



The revival of tobacco dust is also to be noticed and many mysterious 

 "kill all" mixtures are being put on the market as rapidly as possible. 



In conclusion I feel certain that there is a great future for dust spray- 

 ing. As yet it has hardly been touched. The development of new ma- 

 chinery^ is also uncertain. The two must go hand in hand. As entomolo- 

 gists we should take an impartial view and do all in our power to bring 

 about the very best possible conditions for the profitable production of 

 clean and wholesome agricultural products by the elimination of insect 

 pests b}^ the most efficient and economical means. 



NOTES ON THE USE OF NICOTINE DUSTS 



By A. W. Morrill 

 Consulting Entomologist 



During the past few months the writer has given considerable time to 

 investigations of nicotine dusts for the California Sprayer Company, 

 manufacturers of a well known dusting machine and of a brand of nicotine 

 insecticides. Work has been done with many species of insects but the 



