TWE^■TY-^'INTH FRUIT-GROAVERS' CONVENTION. 



169 



and paris green; some of them five, some four, some three, and some 

 two times, and some early m the season only and some late. We also 

 experimented very fully with the arsenite of lime, made up under the 

 so-called Kedzie formula. This arsenite was used on fewer trees than 

 was the paris green, but so far as number of applications is concerned 

 the experiments with it were as extensive as were those with paris green. 

 The lead arsenates and arsenites made up from the soluble soda arsenite 

 and both the acetate and nitrate of lead received their due amount of 

 attention, as did also the manufactured lead arsenate which is sold 

 under the trade name of Disparene. 



''Dust^' Spraying. — Besides this work with the arsenicals used as 

 sprays, we experimented to some extent with the so-called "dust" 

 method of applying the poison, using the paris green in combination 

 with dry slaked lime well powdered and sifted. Various devices for 

 applying the "dust," which are more or less unsatisfactory, are on the 

 market. The devices all use either the ordinary bellows or the rotary 

 blower to scatter the material where it is desired. The former is quite 

 out of the question for orchard use, but there may be a future for the 

 rotary blower. Our experience this season with the " dust " method 

 leads us to consider that with the devices at present available for the 

 purpose thoroughly satisfactory results can not be obtained except on a 

 very small scale. We would consider that were these devices better 

 adapted for work on a large scale, the " dust " method would be quite 

 desirable under such conditions of climate as obtain in some parts of the 

 Pajaro Valley and in some other portions of California where there is a 

 maximum of atmospheric moisture (dew or fog) and the minimum of 

 wind that the "dust" may remain in position upon the foliage and 

 fruit. 



General Results. — When we come to consider the results obtained in 

 the experiments for the control of the codling worm we are confronted 

 by an interesting and very extensive series of facts and figures. The 

 major part of these results fall readily under two heads: damage to 

 foliage and control of the codling worm. 



Damage to foliage when the arsenicals are used as a spray may be 

 either acute or chronic. The acute damage, commonly known as 

 "burning," was noted in a number of cases, and is usually, perhaps 

 always, preventable; that is, it is generally the result of some acci- 

 dental condition, such as the use of a paris green in which there is an 

 excessive amount of uncombined arsenious oxid, a failure to properly 

 stir the spray mixture, thus allowing the arsenical to come from the nozzle 

 in an overdose, overspraying or letting so much of the mixture fall upon 

 the leaves that it runs together in drops, and too small an amount of 

 lime for the arsenical used. Any of these conditions may cause the 



