166 



THE CANADIAN HORTICULTURIST 



July. 1916. 



"Dustins" in the orcluuU of W. H. Gibson, Newoastl-e, Ont. (Jr-hoto by K. S. Duncan.) 



quickly as possible to cover large trees 

 proi>erly and not waste the material. 



(6) So far as I can judge the net 

 cost of the dust spray will not be 

 greater on large trees than that of the 

 liquid spray. The iniaterials cost a 

 great deal more but the time and laboi- 

 required are much less. 



(7) In a wet season like this the dust 

 spray, if it is effective, would be a great 

 boon because the outfit is light and 

 horses could easily take it through any 

 orchard that they could walk through. 

 Moreover, the time required to do an 



orehard is so short that one eould 

 easily, no matter what the weather is, 

 find sufficiently long dry spells to do 

 the spraying. 



Every fruit grower will wish for the 

 success of this new method of spraying 

 and will be disappointed if it should 

 as a result of the season's work prove 

 to be Tinsatisfactory. I hoi>e that if it 

 is found efficient as a controller of fun- 

 gus diseases a fairly good dust prepar- 

 ation for the dormant spray can be 

 evolved in a year or two. 



Dust Sprayer Tested in Mr. Gibson's Orchard 



R. S. Duncan, B.S.A., Port Hope, Ont. 



RECENTLY I had the privilege of 

 inspecting a dust sprayer at 

 work in the orchard of Mr Yv'. 

 H. Gibson, of Neweastle, Ontario, Dur- 

 ham county. 



The duster proper appears to be a 

 simple machine. It consists of a larcre 

 hopper, air tight, which will hold one 

 Imudred and fifty poinids of the dust 

 spray material ; a special feed device 

 equipped with revolving brushes which 

 force the material through a fine 

 screen and finally into the air chamber 

 at the bottom of the hopper, and a high 

 speed fan which produces a forced cur- 

 rent of air directed through the bottom 

 of the hopper. This picks up the dust 

 and carries it through the discharge 

 pipe where it bursts into a dense smoke- 

 like cloud which practically covers the 

 apple tree. 



The accompanying illustrations show 

 tlie duster at work with Mr. W. H. Gib- 

 son directing the spray. The dusting 

 machine cost $150.00 f.o.b. Newcastle, 

 without engine or trucks. Mr. Gibson 

 coupled one of his gasoline engines to 



Tlie outlet pipe or blower was handled 

 in a verticle or up and down motion 

 which distributed the cloud of dust 

 over the trees. In this fashion it is 

 claimed that forty acres can be sprayed 

 iu one day. Whether this can be ac- 

 complished by actual practice lernains 

 yet to be demonstrated. 



When to Spray. 



The time of application ol' dust mix- 

 tures does not differ from the time of 

 application of liquid sprays. They 

 should be applied for the second and 

 third sprayings when pink is begin- 

 ning CO show in the blossoms and after 

 the blossoms have fallen. Tlie claim is 

 made that both insects and fungi can 

 be controlled if spraying is done thor- 

 oughly. 



This dust spray, however, is of no 

 value for the control of oyster shell 

 bark louse and san jose scale on the 

 dornmnt wood. The liquid spray will 

 still have to be used for this applica- 

 tion. 



The chief advantage in spraying with 

 the dust material is the saving in time 

 and labor, especially where a grower 

 has a large acreage to spray. The cost 

 of the materials, however, is much 

 greater, which, perhaps, would be off- 

 set by other factors mentioned. 



As to the efficacy of the dust spray I 

 would not at present venture an opin- 

 ion. This is being tried out in an ex- 

 perimental way this season by Mr. Gib- 

 son, and by the Department of Agri- 

 culture under the direction of Prof. L. 

 Caesar; Provincial Entomologist. 

 Should scab and insects be controlled 

 effectively the dust spray will prove a 

 boon to the large apple groAver. 



the machine and placed the outfit on a 

 set of old trucks. 



Material Used. 



The material used for spraying is 

 known as "Poison Dust Sulphur," 

 which consists of eighty-five per cent, 

 of very finely ground sulphur and fif- 

 teen per cent, of dry powdered arsenate 

 of lead. The quantity recommended to 

 be used per tree is determined by the 

 size and shape of the trees, and also 

 by the thoroughness of the application. 

 This varies from one to two po^inds a 

 tree for each application. This ma- 

 terial was purchased in bags with the 

 analysis stamped on the outside at a 

 cost of six and a half cents a pound 

 f.o.b. Burlington. From personal ob- 

 servation it was svident that a great 

 Avaste of material would occur in a 

 very high wind, and that for best re- 

 sults spraying on a calm day v.^ould be 

 advisMi)!'^. 



Mr. Gibson was spraying trees fifteen 

 years of age at the time of inspection, 

 and the horses walked right along. 



Leaf Curl Disease of Peach 



The cool, moist weather this spring 

 has been conducive to the spread of 

 the leaf cm-1 disease of the peach. 

 Because of this the Ohio Agricultural 

 Station has had numerous complaints, 

 more especially from northern Ohio, of 

 the curling, yellowing and dropping of 

 leaves of peach ti"ees, and of the threat- 

 ened defoliation of the trees. In eon- 

 sequence it has issued a cireular ex- 

 plaining certain varieties of peaches, 

 especially Elberta, Lemon Free and 

 others that are very susceptible. This 

 is caused by the leaf -curl fungus, which 

 lives over as threads of the fungus in 

 the buds, though we do not have leaf 

 curl .outbreaks of a serious character 

 every sea.son. 



The sunaval of the disease in the 

 buds calls for treatment in the early 

 spring before the fungus has attacked 

 the leaA-es. Dormant strength of the 

 lime-sulphur sprays, or of standai-d 

 Bordeaux mixture, or combinations of 

 the two, applied in spring as the buds 



