REPORT OF THE STATE ENTOMOLOGIST 1903 157 



insects. If too much lime is used it is liable to scale off; conse- 

 quently there is a limit to the amount which can be employed, and 

 for various practical reasons we are inclined to believe that 25 

 pounds of lime, 20 pounds of sulfur to 60 gallons of water is a 

 very good proportion. The lime probably aids materially in hold- 

 ing the sulfur and its sulflds (which latter are undoubtedly 

 among the most valuable constituents of the wash), and thus adds 

 to the efficiency of the insecticide by preventing to some extent, 

 leaching of its active ingredients. Our experiments fail to indi- 

 cate the necessity 'of prolonged boiling insisted on in so many 

 formulas. In fact, it seems as though active boiling for 30 min- 

 utes meets every requirement. A wash prepared in this manner 

 appears to be just as effective as one which has been boiled for a 

 much longer time. Salt increases the specific gravity of the 

 liquid and thus undoubtedly aids in keeping the solids in suspen- 

 sion, but so far as chemical action and insecticidal properties are 

 concerned, it appears to have no value, and the same is true of its 

 effect on the adhesive qualities of the wash. So marked is this 

 that we have omitted it from the composition of the wash because 

 of its very problematic value. We are still of the opinion that 

 climatic conditions have considerable influence on the effective- 

 ness of this insecticide, and believe that it should be applied when 

 the trees are dry or nearly so, and that, in order to obtain satis- 

 factory results, no large amount. of rain should fall within three 

 or four days after the spraying. This insecticide gives very good 

 results wherever it can be applied thoroughly and has the advan- 

 tage of being cheaper than any other winter wash, though it is 

 decidedly more injurious to apparatus and exceedingly disagree- 

 able to apply. 



The resin solution [see p. 160 for preparation] was added to 

 several of the washes in hopes that it would materially increase 

 their adhesiveness and likewise their insecticidal properties, be- 

 cause such seemed to be the case in some preliminary indoor ex- 

 periments. Field tests, however, failed to indicate any great ad- 

 vantage resulting from the addition of this material, except 

 perhaps in the case of rains immediately following the applica- 





