108 STATE HORTICULTURAL SOCIETY. 



" The efficiency of arsenical spraying for tlie cnrculio may be considered 

 as established beyond doubt. In this, as in other new enterprises, mistakes 

 have been made, but they have rarely been grieyous, and they have all 

 aided in the final solution of the problem. The practice of spraying for 

 the curculio is a result of success in spraying for codlin moth, although 

 there is record of its suggestion even before Paris green was recommended 

 for the canker worm. Three important problems have perplexed the culti- 

 vator in this connection. First, it has been supposed, both by fruitgrowers 

 and most entomologists, that the adult curculio does not eat, and therefore 

 is not susceptible to poisons; second, the strength of mixture to be applied 

 has been from the first a moot point; third, the composition or material 

 which it is best to use has also been a point of discussion. 



"Several investigators have shown beyond question that the adult cur- 

 culio feeds promiscuously. It will eat leaves, fruits, and flowers, not only 

 of the stone fruits but of other plants. It has also been proved, by (,'xper- 

 imenting with the insect under confinement, that arsenic in any form is 

 fatal to it. It is therefore evident that the proj)er application of arsenical 

 spray to plants upon which the insect feeds must prove effective. 



PEOyED TRACTICALLY EFFICIENT. 



" That arsenical sprays are efficient in practice has been proved for a 

 number of years by fruitgrowers. In fact, the practice was first urged by 

 growers themselves, and they have incited the investigations which have 

 recently been made by experimenters. All the experiments of the last 

 two years have confirmed the statements of growers who have succeeded 

 with the spray. Professor Forbes of Illinois was the first scientist to 

 perform definite experiments upon the curculio. In 1885 he sprayed 

 apple trees to combat the codlin moth, and incident ly observed that the 

 injuries of the plum curculio, which had attacked the orchard, were 

 lessened about onehalf. The first distinct record of the applica- 

 tion of the spray to stone fruits, for the express purpose of combating 

 the curculio, appears to have been made by Prof. Cook in 1887. He 

 sprayed four plum trees with Paris green, and found that a benefit appeared 

 to come from its use, although no untreated trees were observed as a 

 check. The first publication of critical experiments, however, was made by 

 "Weed in July, 1888. During the present season he has repeated the 

 experiments with great care. His tests were made on Early Richmond 

 cherry trees, and fruits of both sprayed and unsprayed trees were 

 individually examined for traces of the curculio. Of 24,000 cherries 

 examined from sprayed trees, 360 were infested; while of 24,000 from 

 untreated trees, 1,483 were infested, showing a benefit from the use of the 

 spray of 75 6-10 per cent. Among the conclusions which he drawls from 

 his experiments, are the following: 'About threefourths of the cherries 

 liable to injury by the plum curculio can be saved by two or three 

 applications of London purple in a water spray, in the proportion of one 

 ounce to ten gallons of w^ater. A sufficiently large proportion of the plum 

 crop can be saved by the same treatment to insure a good yield, when a 

 fair amount of fruit is set. Spraying with the arsenites is cheaper and 

 more practical than any other known method of preventing the injuries of 

 this insect.' 



"In October, 1888, Prof. Cook again published experiments, which 

 showed that plums are benefited by the spray. 



