68 CALIFORNIA CITRUS CULTURE. 
DUSTS. 
A number of valuable insecticides are applied dry, as dusts. They 
are easy to mix and handle, and are often of great service to the farmer 
and orchardist, especially in controlling red spiders or mites on citrus 
trees. 
Flowers of Sulphur. 
For a number of years flowers of sulphur was used alone as a remedy 
for mites on citrus trees. It was distributed over the trees by hand or 
with a blower in the early morning when the foliage was damp, thus 
enabling it to adhere. The warm sunshine oxidizes the sulphur, the 
liberated sulphur-dioxide being the killing factor. Accordingly, sulphur 
is of little avail in the cool summer weather of the coast counties or 
during the winter months anywhere. However, in the warm interior 
districts this is still a very effective remedy for mites. 
Fic. 45.—A power blower for applying dust sprays in 
: orchards. About forty acres can be treated in one day 
with such a machine. It costs $115.00. 
