A Study of the Effect of Accessory Substances on the Adherence of Lime Sulfur Spray to the Integuments of Pine Leaf Scale, Chionaspis Pinifoliae (Fitch)1

Abstract

A number of common spreaders and adherents are here tested out in lime sulfur spray for their effect in increasing or decreasing the amount of adhering spray solution on the integuments of pine leaf scale. The method used in estimating the relative value of the various combinations was to determine quantitatively, by an adapted colorimetric method, the residual sulfur left deposited on fifty scales. It is apparent from the experimental results that the correct amount of accessory material to use is important, and will depend upon the nature of the surface to be covered. The integument of the pine leaf scale is not difficult to wet. The use of an excessive amount of certain materials with lime sulfur resulted in a reduction in the amount of adhering sulfur. From an economic standpoint, it is evident that the use of an excessive amount of accessory material in a spray is a more serious error than the use of too little material.