9 



placed at about 4 per cent of the d'op. In an adjacent orchard of 

 130,000 peach trees not jarred curcnlio injury was placed at 40 per 

 cent of the crop. 



Poisons. — -It has long been known that the beetles feed on the plants 

 upon ^yhich the}^ lay their eggs, and numerous careful experiments 

 have shown that they may be poisoned by thoroughl}'^ sprajang the 

 trees with arsenicals. The results of such work, however, appear to 

 vary somewhat, depending on the relative abundance of the l)eetles 

 during a given season. Many orchardists have adopted the practice 

 of spraying for the curcnlio in preference to jarring, on account of the 

 labor involved in the latter and the frequency with which the work 

 must be repeated to make it etfective. Professor Crandall, in Illi- 

 nois," has shown that curculio injury to apples may be reduced some 

 20 to 40 per cent by a reasonable number of poison applications. The 

 results of persistent spraying by orchardists in western New York 

 are set forth by Professor Slingerland in Bulletin Xo. 235 of the Cor- 

 nell Experiment Station. It is there stated that the growers are 

 almost all in favor of spraying for the curcidio, especially upon plums 

 and cherries. The exact value of arsenicals in controlling the cur- 

 culio on peach has api)arently not yet been determined, though there 

 are numerous growers who spray their peach trees every year and 

 report good results. The foliage of peach is likely to be injured, 

 however, by repeated ai)plications of arsenical sprays, and the grower 

 using these sprays for the first tiuie should proceed witli caution. In 

 localities where it has been established that no iujury results from their 

 use. they are to be recommended. Other stone fruits, while liable to 

 foliage injury from repeated a})plications of arsenicals, are appar- 

 ently not so sensitive as is the peach, but care should be taken at all 

 times that the poison be used as recommended below. Apple and 

 pear are rarely, if ever, injured by the proper use of arsenicals. Of 

 the poisons available, such as Paris green, "'green arsenoid," and 

 arsenate of lead, the latter is least likely to be injurious and should 

 be used where stone fruits are to be treated. Liability to injury from 

 arsenical poisons will be greatly reduced by adding to each 50 gallons 

 of the spray the milk of lime made by slacking 2 or 3 pounds of good 

 stone lime. Where Bordeaux mixture is employed agaiust scab and 

 other fungous diseases, the arsenical may be used in the fungicide, 

 and the milk of lime is then unnecessary. To be reasonably effective 

 in killing the l)eetles, arsenate of lead should be used at the rate of 2 

 pounds to 50 gallous of water. Paris greeu or given arsenoid should 

 not, on stone fruits, be used stronger than 1 pound to 150 or 200 gal- 

 lons of water. On pome fruits a somewhat greater strength may be 

 used without danger of injur}' to the foliage. 



" TUil. !'S. III. Auric. E.\[). St:i.. ]•. .5.5.'{. 

 [Cii-. 73] * 



