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MINNESOTA STATE HORTICULTURAL SOCIETY. 



low zero but simply spraying when the frees are dormant with some 

 compound which will noti injure the trees in that condition and yet 

 is strong enough to kill insect eggs and plant spores which would 

 cause mischief if allowed to remain. Perhaps fhe best way for me 

 to state this matter in the short timie at my disposal is to name 

 to you certain stages of different plant diseases and of insects which 

 occur in winter. We have the eggs of various plant lice — ^^little 

 shiny black specks which you see in the axils of buds, notably the 

 eggs of the apple aphis and of the plum ?.phis. The eggs of the 

 wooly aphis and of the so-called "red spider" are also present in 

 winter. We have the eggs of the scurfy scale and of the oyster 

 shell scale, more or less common in our orchards on older trees. 



FIG. I — Oyster Shell Bark Louse, a. Female scale from beneath; b. same from above; 

 " c. infested tree; d. Male scale. Bureau of Entomology, U. S. Dept. of Agriculture. 



Among plant diseases we have winter spores of the apple scab, which 

 affects both leaf and fruit, as you know ; spores of the black knot 

 of the plum', of the black rot of the apple, of the bitter rot of the 

 apple and plum, as well as spores of plum pocket and, doubtless, 

 spores of other fungous diesases. In the lime, sulphur and salt 

 wash, which, it must be noted, can only be used on dormant trees, 

 or perhaps, just as good and better, the lime and sulphur wash, we 

 have something which will kill these spores and eggs. I will give 

 vou the formulae for both the lime, sulphur and salt, and the Hm'e- 



