OCR Text |
Show Aisenicaljprays Effectiveness of Spraying Mixtures Demonstrated by Field and Laboratory La-boratory Experiments Extensive field and laboratory tests with different nrsonlcnls in killing chewing Insects which attack apple and certain other fruit trees wero made during 1912, 1913 and 1911 by thrco entomologists of tho department. depart-ment. Thcso tests Included laboratory labora-tory and Held experiments in killing tho codling moth, tho larvao of tho fall webworm, tho larvao of tho tent caterpillar, tho larvao of tho tussock moth and of a certain tiger moth and tho Dntana. In addition to testing straight arsenlcnls, a number of compounds com-pounds mid combination sprays also were used both to determlno their effectiveness ef-fectiveness and If posslblo to find out what combinations wero not successful suc-cessful becauso tho sovcral Ingrodl-cnts Ingrodl-cnts In fliem wero incompatible and formed insolublo products which wero either Inert or damaged follago or did other harm. Especial attention was given to tho combination of fungicides fun-gicides and certain aphldlcldcs with arsenates, slnco tho prevention of fungus diseases and aphides Is Intimately Inti-mately associated with controlling tho chowlng insects. Following is n brief summary of tho results reached by tho department's depart-ment's specialists as reported In Department De-partment Bulletin 2TS, Miscellaneous lnccctlcldo Investigations. Arsenate of lead proved to bo th.' most consistent and valunblo stomach poison tested, giving satisfactory results re-sults throughout Uio experimental work . Arscnato of lead is equally, effective either In tho paste or powdered form. Trlplumblo arsenate of lead Is less rapid as a poisoning agent than dip-Iumblc dip-Iumblc arsenate, but Is safer to use on tender follago. Arsenate of lead may ho combined with nlcotlno solutions and lime sulphur sul-phur solution for tho control of certain cer-tain upplo chowlng and sucking Insects In-sects and fungous diseases. For tho control of certain sucking and chewing insects arscnato of lca.l may bo combined with koroscno emul sion. Arscnato of lead, kcroscno emulsion and lime sulphur Is an Incompatible-mixture, Incompatible-mixture, duo to tho formation of cu Insolublo cnlclum soap and tho qttb-sequent qttb-sequent release of frco koroscno. In their experience any combination containing llmo sulphur and soap should not bo used, owing to tho formation for-mation of an Insolublo calcium soap. Arscnato of lead should not bo mixed mix-ed with sodium sulphld compounds, slnco tho solublo sodium arscnato formed Is destructive to leaf tissue Arcnato of lead combined with a commorclal barium tctrasulphld gavo satisfactory control of tho codling moth and caused no follago Injury In tho experimental applo orchard. Tho most promising now Insecticide dovolopcd during tho courso of tho oxperlmontal work Is arsenate ot cal-1 cal-1 clum. This arsenical may bo manufactured manu-factured at n cheaper cost than nr- sennto of lead or may bo readily prepnred at homo. During tho sea-I sea-I sons of 1913 and 1913 arscnato of calcium gnvo encouraging results. In 1911 n commercial arscnato ot cnlclum cnlcl-um pnsto In combination with llmo sulphur gavo very satisfactory control of tho codling moth. "While arsenate of calcium may havo certain limitations, limita-tions, it will doubtless provo of vol-uo vol-uo for tho control of chowlng Insects on certain host plants. Arsenato of Iron and nrsonato of zinc arc not as satisfactory as nrsonato nrson-ato of lead. Arsonlto compounds aro dangerous to uso on tondor follngo. In some Instances, In-stances, howovor, it may bo posslblo to prevent tho solublo arsenic with llmo. Sodium ami potosf 'urn sulphur compounds com-pounds gave folrly satisfactory control con-trol of the Ban Jos-j scale lu some l Ht-uiicog oquallne lime sulphur solu tl'ti They may readily ho prepared nt homo without the uso of hoat. |