37 



REPORT OF EXPERIMENTS WITH LIME, SALT, AND SULPHUR 

 WASH AGAINST THE SAN JOSE SCALE IN MARYLAND. 



By A. L. Quaixtaxce, College Park, Md. 



As a result of experiments by the entomologists of the Division of 

 Entomology, United States Department of Agriculture, and others, 

 it has perhaps been generally accepted that the lime, salt, and sulphur 

 wash, so effective in California against the San Jose scale, is of com- 

 paratively little value in the East, owing to our more rainy climate. 

 Jn the past few years, however, numerous reported cases of its suc- 

 cessful use have awakened renewed interest in the wash, and further 

 experiments have seemed desirable, particularly in connection with a 

 record of weather conditions, which seem to be an important factor in 

 the results following its application. 



The past winter applications of the lime, salt, and sulphur wash 

 were made in three different localities in Maryland, namely: College 

 Park, Prince George County; Annapolis Junction, Howard County; 

 and Sharpsburg, Washington County. 



Experiment I. — At College Park, 20 five-year-old Japan plum trees. 

 badly infested with scale, were treated on March -i. A Pomona 

 barrel sprayer was used, fitted with Seneca nozzles. The wash was 

 made according to the following formula: 



Lime pounds. . 40 



Salt do.... 15 



Sulphur do 20 



Water ' gallons. . 60 



The sulphur and 20 pounds of quicklime were placed in a barrel 

 with 20 gallons of water and steam cooked for one and one-half hours, 

 after which the salt and the remaining lime were added and the whole 

 cooked for one-half hour longer, after which the balance of the water 

 was added. 



At the time of making the application the weather was cloudy, and 

 the temperature ranged somewhat above the freezing point all day. 

 Soon after the work had been finished a light snow began to fall, 

 which alternated with rain and sleet during the night and most of the 

 following day. The trees were wet almost continuously for a period 

 of twenty to twenty-two hours immediately following the application 

 of the wash. Several succeeding days were clear and bright, with 

 the temperature ranging mostly above the freezing point. The pre- 

 cipitation and aspect of sky from March 4 to May 31 is given in 

 the following table, as taken from the weather record book of the 

 United States Weather Bureau, as recorded by Prof. W. T. L. Talia- 

 ferro at the experiment station, about one-fourth mile from the 

 treated trees: 



