90 
JOURNAL OF ECONOMIC ENTOMOLOGY 
[Vol. 16 
severely. It therefore is necessary to be very careful to use a weaker 
solution upon prune foliage when attempting to control red spider. 
Mr. J. S. Houser: We have been doing some work with this pest in 
northern Ohio near Youngstown where it has been prevalent for at 
least three years. This orchard has been carefully sprayed each season, 
using the dormant application of lime sulphur and the full complement 
o 
of summer sprays in which lime sulphur liquid 1-40 was the fungicidal 
agent employed. The dormant strength lime sulphur had failed to de¬ 
stroy the overwintering eggs and the summer applications had failed to 
destroy the hatched mites. However, miscible oil applied in the spring 
was found to be very efficient in destroying the over-wintering eggs and 
the treatment was observed to have a lasting effect throughout the season. 
Mr. E. N. Cory: In Maryland our results have been somewhat 
similar to those in Ohio, but we were unable to get lasting effects with 
miscible oil. During the last two seasons when the weather has been 
very hot, the mite has increased to such an extent that it has caused 
serious damage and the ordinary summer sprays in dry weather have 
caused considerable burning. 
President J. G. Sanders: Did you try self-boiled lime sulphur? 
Mr. E. N. Cory: We used it in one orchard this year with fair results. 
Mr. Philip Garman: In Connecticut we tried several different 
sprays and we had fair success, as a summer spray, with lime sulphur 
with nicotine added. We also had good success with soap solution— 
fish oil soap and ordinary laundry soap. There was a third combi¬ 
nation devised for the control of red spiders on cucumbers in Massachu¬ 
setts, known as “linseed oil emulsion.” The latter spray, I think, gave 
as good control as anything I have ever seen. 
President J. G. Sanders: Is not that emulsion rather expensive? 
Mr. Philip Garman: The cost will not amount to very much more 
than lime sulphur. The total cost was about $1.50 per hundred gallons. 
President J. G. Sanders: The next paper is “The Insecticidal 
Properties of Tobacco Dust,” by P. J. Parrott and Hugh Glasgow. 
THE INSECTICIDAL PROPERTIES OF TOBACCO DUST 
By P. J. Parrott and Hugh Glasgow, Geneva, N. Y. 
Abstract 
Commercial tobacco dusts vary greatly in nicotine content and physical properties, 
the finer dusts killing a larger percentage of the spirea aphis, the currant aphis and the 
apple red bug. Rosy aphis was combated effectively with either nicotine sulphate 
