110 STATE HORTICULTURAL SOCIETY. 



menters in California and Oregon assert that mixtures must be more dilute 

 than those recommended for the east. I am informed by Benj. Hammond, 

 manufacturer of 'Slug-Shot,' who has given particular attention to the 

 behavior of arsenites upon foliage, that trees near the sea-cost are more 

 liable to injury than those growing in the interior states. But our knowl- 

 edge of this subject is yet too meager to allow of generalization. 



''It is well established that several applications are necessary for the 

 profitable destruction of the curculio. There are several circumstances 

 which complicate the practice, however. Spraying trees while they are in 

 bloom, although it may destroy some curculios, appears to be fatal to bees, 

 and there is aj^ossibility that it may interfere with pollination. On the 

 other hand, there is some indication that in midseason the spray is more 

 harmful to foliage than it is early in the season. But if the poison is 

 sufficiently diluted, no harm is to be feared. Spraying three or four times, 

 at intervals of a week or ten days, or oftener if heavy rains occur, appears 

 to be the best practice. 



WHAT IS CONCLUDED. 



" The following conclusions of the whole matter, so far as our present 

 knowledge extends, may be drawn: First, the adult curculio eats foliage, 

 fruit, and flowers; second, arsenic is fatal to the curculio; third, experi- 

 ments and experience prove that spraying stone fruits, in a proper manner, 

 checks the ravages of the curculio; fourth, both London purple and Paris 

 green are efficient, but it appears that London purple is often more 

 injurious than Paris green — white arsenic is more injurious than either; 

 fifth, one pound of poison to 250 gallons of water makes a strong enough 

 mixture for general use, while for spraying the peach a weaker mixture 

 should be employed; sixth, the spray should be very fine and should be 

 applied thoroughly and with great force; seventh, spray should be applied 

 three or four times after the blossoms fall, at intervals of a week or ten 

 days, or oftener if heavy rains occur. Trees should be carefully examined 

 before each subsequent application, and if they have been injured by the 

 previous application, the mixture should be diluted." 



DISCUSSION OF THE MATTER. 



President Lyon asked Mr. Cordley which, in his opinion, caused the 

 injury to the foliage in his experiments, the first application or all together. 



Mr. Cordley : I can not say as to the plum leaves, but in cases of the 

 cherry the damage seems to be cumulative. 



Prof. Taft : In certain experiments I found the old leaves hurt and the 

 younger ones unharmed. Old leaves were hurt by a mixture of one pound 

 to 500 gallons and killed by one pound to 250 gallons. It seemed that the 

 older the leaves the more they suffered. 



Prof. Cordley: A mixture of one pound to 100 gallons was applied 

 early and did no hurt, while one pound to 250 gallons, later, was harmful. 



Prof. Taft : Curculio sometimes appear ten days before the trees bloom, 

 and so it might be well to spray once or twice before blossoming. 



Thos. Wilde: I use white arsenic or corrosive sublimate, but I allow 

 no one to use either for me, and I make each succeeding application 

 weaker. Yet I do not recommend arsenic, because it is not easily obtained 

 pure; and besides, it becomes air-slaked and more soluble and so one can 

 not be sure of its strength. An arsenic solution, too, when the sun comes 



