290 JOURNAL OF ECONOMIC ENTOMOLOGY [Vol. 17 
results with the boiled emulsion. It is oil apparently that does the 
killing. 
Vice-President S. B. Fracker; The next paper will be by F. H. La- 
rop and V. M. Trask. 
FURTHER STUDIES OF PRUNE ROOT BORER 
CONTROL IN OREGON 
By Frank H. Lathrop and Victor Trask, formerly of the Oregon 
Agricultural Experiment Station 
Abstract 
This paper is a report upon experiments conducted in Oregon during the season of 
1922 in the control of the Prune Root Borer, Sanninoidea opalescens Edw. The 
treatments tested include Naphthalene Whitewash and the application of Para- 
dichlorobenzene. 
The Naphthalene Whitewash consisted of a basic formula composed of quicklime, 
copper sulfate, glue, and ground wood pulp, with sufficient water to form a thick 
paint. To this were added mixtures of naphthalene and paraffine in solid solution or 
naphthalene alone. The wash was applied to the tree trunks to a height of 14 to 16 
inches after the soil had first been removed and the bases of the trees protected from 
the naphthalene fumes by means of paper collars or by a preliminary “protective” 
wash. In general, the treated plots showed a reduction in infestation. Best re¬ 
sults were secured by the use of naphthalene-paraffine mixtures applied in connection 
with a preliminary protective wash. 
Applications of one ounce of Paradichlorobenzene about the bases of the trees during 
the first week of September, gave excellent results when left undisturbed until the 
following spring. Larvae situated some distance above the soil level were not 
affected by the treatment. In heavy soils the action of the material was slower 
than in lighter soils. When this material was improperly applied or very young trees 
treated, severe injury resulted to prune trees. 
The present paper is a report of results of applications made for the 
control of the prune root borer (5. opalescens Edw.) in the orchards of 
western Oregon during the summer and fall of 1922. The treatments 
applied include naphthalene whitewashes, 1 and paradichlorobenzene. 
Naphthalene Whitewash Treatments 
Basic Formula. In each plot the basis of the wash was the same, but 
the nature and amount of the active material was varied. The basic 
wash was made up according to the following formula: 
Quicklime. 8 pounds 
Copper sulfate. 34 pound 
Glue. K pound 
Ground wood pulp. pi pound 
Water to make a thick paint 
Tathrop, F. H., and Black, A. B.: Jour. Econ. Ent., v. XIV, pp. 328-336, 1921. 
