Domashneva O. The Ecological Ground of natural protection system for summer barley from Swedish flies (Oscinella pusilla Mg., Oscinella frit L.) in the north Steppe of Ukraine

There are 10 species of stem-hidden pests for the spring barley in the Northern steppe of Ukraine. Among them dominant ones are Oscinella pusilla Mg. (52.6%) and Oscinella frit L. (18.7%). Their frequency of occurrence was 54.2-56.3% and 14.9-22.0%, and the numbers index, 60.2-60.6 and 19.8-27.8 % respectively; other species had low numbers index. Biochemical and quantitative indicators of Swedish damage were determined for different varieties of the spring barley. The author investigated the influence of cultivation methods (terms of sowing, seeding rates, methods of soil treatment, the balanced system of fertilizing, etc.) on the numbers dynamics of these pests; identified 7 species of entomophages for Swedish flies dominant ones are Rhoptromeris heptoma Htg. - 61.2 % and Trichomalus posticus Wesm. - 39.8 %, as well as a number of Swedish flies diseases. Thus because of Pseudomonas septica the losses of pest larvae were 2,3-7,9%, pupae - 1,4-5,1% and imago - 1,7-9,2%. To reduce the number of Swedishflies border spraying of the spring barley with sumi-alpha (96.5%), karate (94.2 %) and detsys (94.1 %) has proved its high biological effectiveness. Using this protection system has made possible to decrease the damage caused by the Swedish fly: for stems of spring barley by 19.1%, for ears - by 3.5% and to increase the productivity of the fornules sort Donetskiy 14 by 3.9 centner/hectare.