MISCELLANEOUS INSECTICIDE INVESTIGATIONS. 41 



experimental apple orchard arsenate of iron was not an effective 

 insecticide for the codling moth. When used at greater strengths, 

 however, this arsenical should give fairly satisfactory results, but 

 would have no advantages over arsenate of lead. 



ARSENATE OF ZINC. 



LABORATORY AND FIELD TESTS. 



Arsenate of zinc was used with very fair success in laboratory and 

 field tests, but fell somewhat below the efficiency of arsenate of 

 lead. This arsenical has no distinct advantages over arsenate of 

 lead. 



ARSENITE OF LIME. 



LABORATORY AND FIELD TESTS. 



Arsenite of lime is an active and relatively cheap arsenical poison. 

 Unfortunately, however, its use is frequently attended with injury 

 to the foliage. 



ARSENITE OF ZINC. 



LABORATORY AND FIELD TESTS. 



Arsenite of zinc was used in both the paste and powdered forms 

 alone and combined with fungicides. In common with other arse- 

 nites the zinc compound is an active poison, but frequently causes 

 foliage injury. Arsenite of zinc combined with milk of lime and 

 arsenite of zino mixed with lime-sulphur caused considerable burn- 

 ing in the experimental apple orchard during 1912. In 1914 arsenite 

 of zino (paste) added to slaking lime and then mixed with lime- 

 sulphur solution gave practically no foliage injury, but the value of 

 the arsenical was apparently impaired. Arsenite of zinc (paste) 

 added to slaking lime for Bordeaux mixture gave excellent codling- 

 moth control and caused no foliage injury. It is possible that the 

 latter combination may be of value in sections where apple growers 

 use Bordeaux mixture along with an arsenical for the control of the 

 codling moth, bitter-rot, and blotch. Commercial arsenite of zinc 

 in combination with Bordeaux mixture was tested in a vineyard dur- 

 ing the season of 1914, with satisfactory results. 



MISCELLANEOUS ARSENICALS. 



The following arsenical compounds were also tested at the labora- 

 tory : Arsenic sulphid, arsenic tersulphid, and arsenic trioxid. These 

 materials are destructive to leaf tissue and therefore undesirable in- 

 secticides. 



NONARSENICAL COMPOUNDS. 



Several compounds containing no arsenic were tested, namely, 

 barium chlorid, barium sulphate, calcium chlorid, copper oxid, lead 

 acetate, lead carbonate, lead chromate, lead oxid, lead peroxid, 



