36 



inches of the bark and the spraying- being very thoroughly done. At a 

 distance of 18 inches, as tested by spraying on one's hand, the mist or 

 spray was barely warm: at a distance of 12 inches, fairly hot. and very 

 hot at from 4 to 6 inches. The bark of the trees sprayed was cold to 

 the hand as soon as spraying stopped. This hot-water spray brought 

 to bear closely on the scale insects, it was thought, would kill them, 

 although it would of course be impracticable to make such close- 

 range application in general practice. On the contrary, however, 

 the scales remained in a vigorous, healthy condition, and apparently 

 did not sutler in the least from the warm douche. 



The results, therefore, gained by the lime, sulphur, and salt wash 

 may be properly ascribed, it is believed, to a true insecticidal value of 

 the substance rather than to the temperature of the application. The 

 trees treated with this wash remained nearly snow-white, little, if any. 

 of the mixture being taken off by the light snow and rain of the 25th 

 and 26th instant. Discoloration of the Diaspis began to be noticed on 

 the 27th instant. On April 13 the Diaspis scale insects killed ranged 

 between 20 and 50 per cent on the young, vigorous limbs. All were 

 dead on the old trunk, where the wood was in a very unhealthy condi- 

 tion owing to the completeness of the infestation, boch by the Diaspis 

 and the Aspidiotus. The San Jose scale, so far as investigation could 

 determine, seemed to be killed completely: no insects were found 

 on the young, vigorous shoots or older wood. The trees were still 

 whitened with the wash, which had not been carried off Co any very 

 great extent by the heavy rains of April 11 and 12. The infested 

 trees, especially those that had been pruned back, made a very vigorous 

 growth, and the fruiting and growth of the others were entirely 

 satisfactory. 



In this experiment, which differed so remarkably in results from 

 other experiments made in the East with this substance, it must be 

 noticed that the weather conditions were exceptionally favorable. 

 The application was made on March 23. and no washing rains followed 

 until April 11 or 12. the light rain and snow of the 25th and 26th of 

 March being not enough to vitiate the wash particularly, as very 

 little of the snow rested on the trees, and much that did gain lodgment 

 fell or was blown off subsequently. A very light shower occurred on 

 April 1. but the first heavy downpour and long rain occurred on the 

 night of April 11. 



This experiment would seem to indicate that if one could count on a 

 week or two of good weather following an application, the lime. 

 sulphur, and salt wash might be as beneficial in the East as on the 

 Pacific coast, it- cost is inconsiderable compared with the other treat- 

 ments for the San Jose scale. 



During the summer of 1900 the writer spent considerable time in 

 California and saw a great many deciduous orchards that had been 



