244 KEPORT OF OFFICE OF P^XPEKIMENT STATIONS. 



The Maryland Station has likewise devoted considerable attention 

 to an investigation of the siili)h>ir washes." In the first e,.\j)erinients 

 with suli)luir washes at this station it was reconnnended that they l)e 

 applied late in November or in December, especially if another appli- 

 cation could be given in early spring. The best time for applying 

 the wash, however, was found to be in spring just before the buds 

 begin to swell. No difference was noted in the effectiveness of the 

 wash whether salt was added or not, whether all of the materials 

 were boiled together or part boiled and the others added later. In 

 subsequent experiments a comjjarison was made of the effectiveness 

 of various fornndas of lime-sulphur-salt washes. Good results w^ere 

 obtained from all the fornndas used, but it appeared to be desirable 

 to use at least 20 pounds of lime and 15 pounds of sulphur to each 50 

 gallons of water. The solutions boiled by fire gave better results 

 than the self-boiled mixtures. The omission of salt seemed in some 

 cases to be without effect, while in others it appeared that the effective- 

 ness of the wash was thereby diminished. The results obtained from 

 these experiments indicated that the California wash may be applied 

 in the late fall or early winter with as good results as at other seasons 

 and the fornuda recommended was 20-15-10-50. Recently the vari- 

 ous practical questions connected wnth the prei)arati()n and applica- 

 tion of California washes have been reconsidered at the Maryland 

 Station, and it is still recommended that the California wash is the 

 most satisfactory insecticide for the San Jose scale, llecent experi- 

 ments have demonstrated more clearly the superiority of this wash 

 over other insecticides. While the lime-sulphur mixture is consid- 

 ered as a treatment for dormant trees, it appears that where only one 

 application is possible the treatment should be postponed as late in 

 the spring as possible before the buds have begun to open. 



The California wash prepared according to the formula 20-15-10-45 

 was applied to peach trees in February by the Mississippi Station.^ 

 The mixture was boiled for forty-five minutes and was applied 

 promptly. It is recommended, however, that the lime and sulphur be 

 boiled forty-five minutes, after which the salt is to be added and the 

 mixture boiled for fifteen minutes longer. December is regarded as 

 the best month for the application of the California wash in Missis- 

 sippi. February might be a better time if it were not for the lia- 

 bility of persistent rains during that month. In sunnner the wash, 

 made according to the same formula, is recommended for aj^plication 

 to the trunks and large branches of the trees by means of brushes. 

 It appears that San Jose scale may be exterminated by two applica- 

 tions of California wash after peach trees have been severely pruned 

 back. 



a Maryland Sta. Buls. 90, 99, 107. 

 J> Mississippi Sta. Bui. 90. 



