Page ib 



BETTER FRUIT 



November, 1920 



Late Developments in Arsenical 

 Insecticides 



Continued from page 10. 



I In-m. Arsenite of zinc and arsenate 

 of calcium are new and not well 

 known. The dealers are not well in- 

 formed about them, and if you were 

 to obtain them you would probably 

 have to deal directly with the manu- 

 facturers, though you should be able 

 to get your dealer in town to put them 

 into his stock. Arsenite of zinc has 

 been on the market several years and 

 we have experimented with it at the 

 Experiment Station. It is noticeable 

 that it contains a high percentage of 

 arsenic compared to the cost, that it 

 has a low water solubility, and a fine 

 texture. If vou wish to use it, I would 



suggest that you begin on the potato 

 and that you feel your way into its 

 use in your orchards. I have used it 

 at the Experiment Station on potatoes 

 with excellent results for several years 

 and do not hesitate to recommend it 

 for the potato beetle. Arsenate of cal- 

 cium is a newer product and we have 

 found it very satisfactory as a rem- 

 edy for the potato beetle. Its low cost 

 particularly commends it, while it is 

 very fine in texture. 



I come now to white arsenic, which 

 is produced in the Montana smelters 

 in large amounts. When in 1917, in 

 connection with the outbreak of grass- 

 hoppers in western Montana, we were 

 in need of large amounts of poisons 

 and could not get Paris green or ar- 

 senate of lead because of the unusual 



Rest 



If you were a tree, 



After a big crop and long summer, 



You would want a rest, 



A rest from growth and insects. 



Give your trees an early bath with 



ZENO 



It will kill the various scale,— stop their damage, 

 Destroy the eggs of red spider {Bryobia) and aphis, 

 Which would later mean millions of insects, and 

 Destruction to the crop— harm to the trees. 



ZENO 



Is an internationally used 



Miscible oil spray, and these are reasons why 



It has proved the best by years of test. 



MANUFACTURED ONLY BY 



Eastbay Chemical Co., Inc. 



of Emeryville, California 



[Zeno may be had of your local Distributor, Fruit Company 

 Exchange, or by writing to us direct] 



SPOHN & WING, Northwest Agents 



223 Sherlock Building, Portland, Oregon 



conditions due to the war, we natur- 

 ally thought of this supply of white 

 arsenic in Anaconda and Great Falls. 

 By a special arrangement I was able 

 to get refined white arsenic, and we 

 used it as a substitute for Paris green 

 in the poison bran mash formula 

 which is so universally used in the 

 control of grasshoppers. The results, 

 while not quite as good as with Paris 

 green, were nevertheless satisfactory 

 and we used large amounts of this 

 poison in three or four counties in 

 that year. We have found more re- 

 cently, however, that the crude white 

 arsenic just as it comes from the smel- 

 ter is more satisfactory for our pur- 

 pose because of its finer texture. The 

 granules of the refined product are 

 really quite coarse and because of this 

 coarseness it is not possible to so thor- 

 oughly poison the particles of bran. 

 We believe that the crude white ar- 

 senic in the poison bran mash form- 

 ula, both for grasshoppers and for cut- 

 worms, has a bright future. Various 

 other states are now using it and con- 

 siderable has been written during the 

 last year or two in the entomological 

 journals. 



I want to call your attention, also, 

 to one more interesting thing about 

 white arsenic. In certain work which 

 we have been carrying on at the Ex- 

 periment Station we have received 

 some encouragement in the hope that 

 white arsenic may be used in spray- 

 ing potatoes. White arsenic is be- 

 lieved to be very soluble in water and 

 one would think that it would be im- 

 possible to use it for spraying pur- 

 poses. While we cannot fully explain 

 the fact, we have found that we can 

 spray potatoes with white arsenic, kill 

 the potato beetles, and yet not injure 

 the foliage at all. We have mixed it 

 with water and sprayed the mixture ai 

 once upon the potato foliage and the 

 failure to injure the leaves is perhaps 

 explained in part by the short period 

 of time that the arsenic was in the 

 water, for when sprayed on the vines 

 the water evaporated very quickly. 

 We did not use any unusual haste in 

 spraying. Our first experiment was 

 with the refined white arsenic and 

 later we used the crude product ap- 

 plied as a dust and our results were 

 even better, due, we believe, to the 

 fineness of the crude product. We ex- 

 pect to continue our experiments. Do 

 not understand me as saying that I am 

 remommending you to use either the 

 refined or the crude white arsenic in 

 spraying or dusting potatoes. On your 

 own responsibility you may experi- 

 ment as we have done, and I may say 

 that under the climatic conditions 

 which we have here in Montana there 

 is some prospect thai we may be able 

 to save a considerable amount of 

 money on arsenicals used in poisoning 

 potatoes, and we probably are all 

 aware that by far the greater part of 

 the arsenical insecticides used in Mon- 

 tana is used on potato vines. 



