256 Report OF THE DEPARTMENT OF ENTOMOLOGY OF THE 
SERIES II. SPRAYING EXPERIMENTS TO DETERMINE 
THE EFFECTS OF CRUDE PETROLEUM UPON 
HIBERNATING SCALES. 
The experiments of this series were conducted in Orchards 
Il, III and IV. | 
ORCHARD II: PEARS. 
The experiments of Series II were begun in this orchard 
which consists of 101 pear trees, nearly all of which are standard 
Bartletts. The trees were planted about six years ago and 
except for the first two years have received but little care. 
During the past four years the orchard has been in sod. It is 
quite probable that some of the trees were infested when 
planted but the scale was not noticed until the spring of 1898. 
When the experiments were begun in 1900 most of the trees 
were extensively infested, many being encrusted on the trunk 
and larger limbs. Before the experiments were begun they 
were carefully trimmed and the orchard was divided into two 
sections. The first, containing 54 trees, was treated with crude 
petroleum, and the second, containing all of the remaining trees, 
except a few reserved for checks, with hydrocyanic acid gas as 
noted in a subsequent section of this bulletin. 
Summaries of the spraying experiments and results in this 
orchard are given in Tables IV, V, VI and VII. The check 
trees are not recorded in the tables. In every case the scales 
had multiplied rapidly. The live ones were abundant upon both 
the new and old growth. 
