20 The European Elm Scale 



or ten gallons were sprayed on each tree, and the appearance of the 

 bark after spraying showed that apparently the whole tree in each in- 

 stance had been well covered. 



Counts of one thousand dead and living scales were made on March 

 7th, 1907, giving the following results : Dead, 286 ; living, 714. The 

 insects counted were all on smooth twigs which were green and in good 

 condition. Some were smooth, others rough with projecting plates of 

 cork. Some of the insects counted were clustered about the bases of 

 twigs or in the axils of buds ; others were ranged along the bases of the 

 projecting ridges of cork. More were counted in the latter situation, 

 for they are far more numerous there than upon the buds or the 

 leaf sears. At the time when the count was made these twigs were still 

 grey with the lime-sulphur and appeared to have been well and thor- 

 oughly sprayed. 



Female scales were present in considerable numbers on the under- 

 sides of the lower branches all through the summer following the 

 spraying. They were not washed away by the gardener, and received 

 no treatment of any kind after the first spraying with lime-sulphur. 

 Until late in autumn these trees made a vigorous growth and showed 

 no signs of injury due to the scale. The leaves remained dark green 

 and glossy until late in October. On September 16th, 1907, they were 

 handsome and thrifty young trees. 



An examination of these trees December 13th, 1907, showed many 

 winter larvae on leaf scars, in the axils of buds, grouped in irregular 

 rings about the bases of small twigs, or partly concealed in and around 

 the semi-cocoons of the dead females or within and around rifts and 

 crevices in the bark. Dead females were fairly abundant on the un- 

 dersides of the lower limbs. These six trees had been well-sprayed 

 February 12th, 1907, with lime-sulphur. They had not been washed 

 later in the season with the garden hose. Winter larvae, abandoned 

 male cocoons, and dead females were abundant enough in the winter 

 following to justify the statement that these trees in the winter follow- 

 ing the spraying with lime-sulphur were still moderately infested with 

 the Elm Scale. They would be benefitted by another spraying. 



LOT VI 



Two American elms of unknown age. Height 40 feet, girth 3 feet, 

 6 inches. Badly injured in the summer of 1906, when many of the 

 lower branches were in a dying condition and the leaves were prema- 

 turely yellow in the lower portion of the tree. In February, 1907, 

 hibernating larvae were present in great abundance. Sprayed Feb- 

 ruary 12th, 1907. Count of living and dead larvae made March 7th, 

 1907. Living scales in one thousand then numbered 667 ; of dead ones 



