4 THE COLORADO EXPERIMENT STATION 
plum trees severely attacked. In the report for 1902 Professor Gil¬ 
lette reported his discovery of it upon the leaves of white ash trees 
in Denver. 
Though the insect has been previously reported in various ento¬ 
mological publications, and notes have been given upon habits and 
portions of its life history, nothing, up to the present bulletin, has been 
published upon its control. 
In Mesa county the Howard scale was found, by the writer, to 
be doing much damage. It was found in practically all localities where 
its food plants were known and at elevations above sea level varying 
from something over 4,000 feet to nearly 7,000 feet. Dr. S. M. 
Bradbury, horticultural inspector for Mesa county, reports that what 
he has taken to be Howard ScaT has been known in the Grand \ r alley 
as a pest upon pears and other fruits since they were first grown 
here. In many instances fruit growers observing the infestation of 
their trees by a scale insect had suspected the presence of San lose 
scale, while others supposed it to be the Putnam scale common in other 
states upon certain shade and fruit trees. 
The fruit growers and fruit growers’ associations of the Grand 
valley have given hearty co-operation in offering their orchards and 
mater.als for experimentation and otherwise aiding in bringing new 
data to light. Also acknowledgements are due members of the Bureau 
of Entomology at Washington for cuts furnished and determinations 
made; to Miss Miriam A. Palmer, entomological artist, of the Experi¬ 
ment Station for original drawings of the insect, and to Professor Gil¬ 
lette for valuable suggestions and much special assistance given. 
FOOD PLANTS. 
Notwithstanding the occurrence of this insect upon shade as well 
as fruit trees it is primarily an economic pest of the latter. In my 
•observations it has been taken upon the following fruit trees: pear, 
prune, plum, almond, apple and peach. By far the greatest injury 
has been done to pear and by many orchardists it is popularly called 
the ‘'pear scale.” 
Bartlett pears seem to be most commonly infested of varieties 
grown in Colorado. Certain varieties of fruit will often become heavily 
infested and require spraying long before sorts more nearly immune 
show any noticeable number of the scales. 
Next to the near, the prunes and plums seem to be the most suscep¬ 
tible. It seems that Wild Goose and other varieties of American plums 
show infestation more generally than the Japanese varieties. Silver 
prune trees are often found encrusted. Almonds, though grown to a 
limited extent in Western Colorado, seem to be quite susceptible to 
its ravages. 
It is rather the exception than the rule to find apples attacked. 
A singular preference is shown, however, for the Grimes Golden. 
Scores of instances have been noted where trees of this variety show 
infestation and other varieties growing near by are totally exempt. 
