^•0 MASSACHUSETTS HORTICULTURAL SOCIETY. 



instances such an absurdly low proportion of the insects died 

 that this line of experimentation was soon abandoned. The 

 reason for this extraordinary difference in the efficac}' of these 

 washes may be laid partly to differences in the average winter 

 temperature between the two sections, and partly to the great 

 difference in precipitation in the early part of the winter. 



Following these early experiments, many other substances, in 

 many combinations, were tested, and, not to Avorry you with 

 details, the practical outcome has been that for dormant trees 

 affected by practically any scale insect, the best wash beyond all 

 doubt was shown to be whale-oil soap in considerable strength. 

 Some species are more susceptible to the action of the wash than 

 are others. Even against the extremely hardy San Jose scale, 

 one and three-quarters of a pound of the soap to the gallon of 

 water, put on thoroughly, has proved absolutely effective. It is 

 advised that the applications be made in the autumn after the 

 leaves fall, and again in the spring before the buds burst. Little 

 or no harm will be done if the application be made at even a 

 later date, since in April peach trees in full bloom have been 

 treated with no serious consequences. Experiments on a large 

 scale seem to show that the fall application has occasionalh' an 

 injurious effect in limiting the amount of bloom the following 

 spring, but the increased vigor of the plant probably more than 

 offsets the falling of the bloom. 



The greatest difficulty with the soap washes, and one which 

 m.ust be obviated before uniform results can be hoped for, is in 

 the varying strength and character of the soap used. Xo two 

 brands of soap on the market are alike, and the differing results 

 which are obtained by experimenters are undoubtedly due in 

 large measure to the character of the soap itself, in connection, 

 of course, with the varying climatic conditions. In addition to 

 securing a good strong caustic soap, one is wanted which, at the 

 strength employed on cooling, will not become a semi-solid or 

 glutinous stringy mass, as do most of the ordinary soaps and 

 also many of the hsh-oil soaps of more recent nuiuufacture. 

 The old whale- or fish-oil soap employed in the original experi- 

 ments could be sprayed in solution at three pounds to the gallon, 

 and this is a most necessary characteristic. It is liighly desira- 

 ble, therefore, that soap makers should be encouraged to under- 

 take the manufacture of a definite brand of soap which can be 



