MONTANA HXPERIMENT STATION. 141 



Dll'I'lXii l.\ AKSI'INATI-: OF Ll-IAl). 



A\ the writer's sii<;'i;'estion arsenate of lead, soc-:rel ivnv.x tlic 

 "owker Insecticide Company, was used. Tlii.^ sri')s^anc'^ luis cer- 

 tain marked adxanlag-es oxer I'aris ^reen as 3i'. arsenical inscctici'le 

 t'oi use on tlie foliaiie of plants. lieinj^^ in.-^ "vln')!'.' in water it mav 

 l;e .■•y-p'ied to tender lea\es in much greatc strenrMli tlian is sa'O 

 with Paris L^reen. And there are x'ery few insects, if any, that can- 

 not ]n killed hy it or drixen from the ])lants spra}'"d v\itli li. More- 

 ox t r, it remains cni the folia.5;e much more persistently than does 

 I'r'.ris ;:reen, and hence is \ery desirable in a climate with frecjuent 

 raips that would easily wash off an a])plication of Paris i^reen. 



\\'e sui^'i^ested to Mrs. ^\'illiams that she try di])pin^- her i)lants in 

 the substance before plantin*;- tliem in the field and then follow up 

 this treatment with later spraxs as new foliafje ap])eared. It was 

 felt that if the beetles could be drixen off from the new ])laii'^ the 

 bed xx'ould be free ex'er afterxvard. 



Mr. lones watched this test and reported that dipped plants were 

 entirely immune for about two weeks after setting- an i after that 

 leno-th of time the beetles g'radually appeared and fed oi" the nexx' 

 Lioxxth that was beini^' put forth. The foliag'e xvas then sprayed 

 and the plants were ag'ain immune, but it was noticed that the plants 

 were not doing- well and it was found that the ingenious beetles were 

 feeding on the roots! It will be remembered that it is the habit 

 of these beetles to hide among the roots in the soft soil and it is not 

 surprising, that impelled by hunger, they fell to feeding on the roots, 

 l^eside hndiiig the roots of the ])lants gnawed, Mr. Jones took the 

 troul)le to make a microscopic examination of the contents of the 

 intestine and concluded that it was compc^sed of what had been 

 eaten from the roots of the strawl)err_x\ The practical ccMiclusion 

 drawn from this test is that, while the use of arsenate of lead in 

 the manner indicated cannot be relied upon to keej) the bed free 

 trom ihe l)eetle, the treatment is prol:)ably xery much better than 

 nothing. ] )i|)])ing the i)lants before setting them is easily done and 

 the cost and trouble of spraying two or three times with arsenate of 

 lead at the rate of five pounds to fifty gallons of water is not great. 



The one result of our inxestigations that appears to be of greatest 

 practical significance is the discovery of the fact that the trouble 

 irom the pest arises from the presence of great numbers oi the 



