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Show BUYING SPRAY FOR FRUIT TREES Fruit growers are advised on the importance of quality of arsenate of lead as a spray in the following Statements made by B S. Hall of the Fruit Growers' association, with headquarters head-quarters in Ogden : II is now a well established fact thai the laws in regard to the manufacture of spray chemicals have been and' are too lax Arsenates of lead, far within the requirements ol the law' both as to the arsenic oxide, lead, and water soluble arsenates have done so much damage by scorching and bave proved so powerless to eomba' the ravages of insects that growers are awakening to the fan that something some-thing is essentially wronc Let us consider first the physical qualities or arsenate of lead In regard re-gard to these the law says absolutely absolute-ly nothing, and yet they are of importance im-portance equal to the chemical content con-tent Arsenate of lead with water lrvS ihan 50 per cent is designated as a paste and yet how few growers have ever seen an arsenate of lead I ha t Is a paste' You are accustomed to a mixture that appears to be abou half solids in the bottom and wati I on top This is a certain sign of pooi physical qualities (also chemical impurities), im-purities), for if arsenate of lead wili not stay in suspension In the almost '.ii per cent of watei in which II is shipped it stands to reason that II will sink rapidly In the spray tank, whereas a lead that i3 really a paste and stays in a paste will show like suspension in the spray tank. In the western states the prominent fruit associations hae for years been bu ing a perfect paste. Secondly, let us consider grit. The most serious losses due to grit in arsenate of lead have not been from ( utting of the pumps, though this complain! is common enough, but through the abrasions or little holes! made in the skin of the Truit. This grit is as hard and sharp as bits of -lass and when forced by the pumps against the tender skin of the apple or other fruit penetrates the skin, with the result that dark spots eventually even-tually develop wherever the skin is broken This trouble has been generally gener-ally attributed to some sort of iun-gU8, iun-gU8, but an examination of the fruit J with n magnifying glass will dis-close dis-close in the center of the dark spots a Bllghl abrasion of the skin. The best way to detect grit in ar senate of lead is lo place a little of I the paste in the palm of the hand and rub It with your finger, when the I rii is easily felt Fineness and Texture. Adhesion Is chiefly dependent upon i he fineness to which the arsenate of lead is ground and the nature of the particles. When dried out and look-l look-l ed at under the microscope the par-' par-' tides should have a flat, smooth appearance ap-pearance of infinite fineness-, not coarse or of a sharp irregular form. Arsenate of lead which cannot be frozen without injury, or which hardens hard-ens v.hen dried out. will have the last named appearance but that which is uninjured by freezing, and when dried rumbles to a powder when touched, touch-ed, is the perfect product Arsenate of lead of this character will adhere lo foliage and fruit 'from 25 per cent to 50 per cent longer than the coarse material, thus giving longer and more complete protection. An Insect will readily eat a minute, min-ute, flat shaped particle, while it will clear off and shove to one side the coarse sharp poisons. This observation obser-vation is based upon results obtained from watching insects while feeding, under a powerful glass. To sum up In regard to the phys-j ical properties of arsenate of lead: It should be and stay a paste in ihe original container It should be of the greatest fine- I ness. It should be free from grit It should be uninjured by freezing. freez-ing. It should when dried out, crumble! to a powder 1 if n has the qualities named a it will mix easily and quickly. U Chemical Purity I The law of 1910 in regard to senate of lead paste says ih-.re :haf not be over 50 ppr cent water ant not oor G-4 of 1 per cent frc of wsV ter soluble arsenates Nothing whall ever is stipulated in regard to totM purity, and in thai omission lies tflj Joker of the whole arsenate of leal business. it Almost any arsenate of lead wlfc show on analysis less than 1-2 of . per ent of water soluble arsenatiB but if the total purity is not pJ" tent, the impurities, when Hie spral.1 is on the trees, will break down anT bring about the release of such af? excess of free arsenit as frequently cause scorching. When it i8 iindell stood that the impurities in most al Jj Benates of lead are from ". per cei I to 8 per cent, exclusive of the free al I senates, and that they are made i I of nitric acid, sulphates and chloride , it is obvious that scorching aris through their direct action on tl 1 toliage and fruit as well as thrmig I their indirect action on the arBel I ate of lead ll the total chemical pul I ity is !ift per cent or over no chain ical reaction, causing crystallizatld I take.s place when di-piumbic 1 15 pel cent oxide i arsenate of lead is frfl zen : it will not harden when drlfl out. but on the contrary crumble III1 to a fine powder and mix freely wita water The reason why (apart frol the physical quality) a f'0 per ceW I pure arsenate of lead has greater pof zoning power than the impure artflj tie is because its chemical nature m such that the 15 per cent arsenit oa ide is entirely available as a pojl son Any di-plumbic arsenate of leap when used with lime sulphur in tA r;m bincd spray show- a black preciff Itation In the bottom or the ?pr$l tank, but impure arsenate of lefl shows almost twice as much a? tm pure, thus indicating a great loss ft available poison Tri-pluinble arsenate of lead (12 lJj per cent arsenic oxide) is poor ptadj tice on apples, as its poisoning pofl er Is very slow, and if less than & per cent pure will scorch fully aC much as di-plumbic arsenate of Iea4 Pure tri-plumbic arsenate of lea I should be used mixed with self-boD I ed lime sulphur on peaches and otl I er tender growths where such fol age is unusually tender, as in CeoBj gla; no scorching will result. ThesJ two sprays make such a perfect cbenfl icnl combination that practically nfl sediment will be found in the spraf lank. To sum up in regard to the chem(T cal purity L When the total purity of arsenatjt of lead is over 99 per cent, its kill? ing power nnd adhesion are at tbj maximum It will not scorch. il All the arsenic oxide in il is avafl able as a poion : coil- i a e : h t vVt. pounds to 50 gallons of water givfl greater protection than to 5 pouiidc tof impure arsenate of lead, savM I troni 1-.. to 1-2 the cost per spra tank of 50 gallons Once the growers thoroughly under Island the above faets. regarding th physical and chemical properties ot; arsenate of lead, they will cease C : consider the price of paramount irffa portance, hut will demantl arsenSB of lead that will show the greatajw 1 net profit in returns of fruit fct grower may save a few cents peCfc I acre in the original cost by buying i an arsenate of lead of 'ess than i I per cent purity, but this apparel I saving of cents will result in an ac I tual loss of dollars by the end of tn season. i i . |
