86 FUMIGATION METHODS 
cussion regarding daylight fumigation in California. 
The following interesting letter from R. P. Cundiff, an 
expert on this subject and Chairman of the Riverside 
County Board of Horticultural Commissioners, is of 
timely interest: ‘‘ What I say upon this subject is 
mainly from a local standpoint. While I seriously 
doubt the practicability of daylight fumigation in any 
locality of southern California, Iam not prepared to 
maintain that in some localities, during certain 
climatic conditions, and for some varieties of scale, it 
might not be done with reasonable safety. However, 
I know of no practical fumigator who has ever advo- 
cated it. Iam under the impression that those who 
are giving such learned opinions on this subject are 
possessed of more of a theoretical than pra¢tical knowl- 
edge of fumigation by hydrocyanic acid gas. 
‘In Riverside County we have found it necessary 
to fumigate but little for black scale, for it has never 
assumed the proportions of a serious pest, as in some 
of the coast counties. Our fumigation has been almost 
entirely for red scale. It is a well-known fact among 
fumigators that it requires almost double the quantity 
of cyanide to kill red scale that it does for black or 
brown scale. This must be taken into account when 
we come to discuss the proposition of daylight fumiga- 
tion. Another consideration is the difference in tem- 
perature. Riverside, being an interior county, is sub- 
jected to several degrees more heat than localities near 
the coast. Another point that should be considered is 
the season of the year when the work is performed. 
Fumigation for black scale, to be in any degree effect- 
ive, must be done during the fall and winter months. 
