DIGITALNA ARHIVA ŠUMARSKOG LISTA
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ŠUMARSKI LIST 1-2/1967 str. 84 <-- 84 --> PDF |
The mortality in the controls was 16"/o in total, (Graph 16) of which the normal mortality accounted for 4l;´,o, while the remainnig 127o kill was due to atacks of tachina flies. Conclusion On the basis of the performed experiments it was found: a) that the boric acid applied alone has an insecticidal effect although a very poor one; b) added to the biopreparation boric acid increases its insecticidal efficiency; c) the addition of boric acid to the biopreparation stimulates the caterpillars to a more intensive eating and thus they are introducing into their body more contaminated food, whereby also the possibility of infection increases. The mechanism of the activity of boric acid has not been studied thoroughly as yet. The authors assume that boric acid stimulates the development of latent organisms found in the digestive tract of the insects, while under normal conditions they are harmless for them. This problem calls for a protracted study, and it is going to be the subject of further investigations by the authors. This conclusion relates to the article by Opatički K. and S. published in »Sum. List« 11/12 1966. under the title: »Possibility of increasing the insecticidal efficiency of the home-made bacterial biopreparation Baktukal«. Opalički K. i S. RAISING RESISTANT SPRUCE STANDS IN THE GORSKI KOTAR REGION Summary The author discusses the problem of raising resistant Spruce stands in the Gorski Kotar region, Croatia. He examines the occurrence of Picea excelsa var. viminalis Caspary. Further, he underlines the advantages of this variety as compared with European Spruce especially as regards its greater resistance to damage from ice and snow, and proposes an exhaustive study of its silvicultural and technological characters. He recommends that when establishing new Spruce stand this variety should be spread over as wide areas as possible. This summary relates to the article by Vajda Z. published in »Sum. List« 11/12 1966. under the title: »Raissing resistant Spruce stands In the Gorski Kotar region«. Vajda Z, ŠUMSKO GOSPODARSTVO »MOJICA BIRTA« - BJELOVAR MATOSEV TRG 1 — Žiro račun: 312-1-964 — Telefon : Kućna centrala 42-60, 42-58, 42-75, 42-77 — Direktor: 42-56 — Pomoćnik direktora: 42-56 — Sekretar: 52-65 Komercijala: 42-59 sa svojim radnim jedinicama proizvodi: Hrastove i bukove trupce za furnir i pilansku preradu Rudno drvo hrasta i otl. Celulozno drvo bukve i mekanih lišćara Ogrjevno drvo bukve, hrasta i otl. Sadnice četinjara Ratarske proizvode, kukuruz i pšenicu. U svojim lovištima ima kvalitetnu jelensku i srneću divljač. |