Strіgun A. Ecological grounding of forecast's methods of the beet weevils Bothynoderes punctiventris Germ. and Tanymecys palliatus F. in conditions of the Central Forest-Steppe of Ukraine.

. The object - sowings of the sugar beet, B. punctiventris and T. palliatus. An aim - was to define more precisely the ecological characters of development and reproduction of B. punctiventris and T. palliatus in the modern conditions of farm management and elaborate the methods of forecast for many years and long-term period. The methods - laboratory, field tests. The novelty - It was carried out the distribution of the territory of Ukraine into different levels of population density, reproduction and prolongivity of the outbreaks of two the main species of the beet weevils. It was defined more precisely the effect of the diverse protection systems of the sugar beet on population dynamics and tropic orientation of the pests. For the first time in agricultural practice it was introduced a coefficient of aggregation of B.punctiventris population. It gives a possibility to make a correction when evaluating a degree of the threat from the pest. There were established the ecological parameters as an effective heat sum (above 100 C), hydrothermal coefficient, prolongivity of sunlight, sun activity, that caused different intensiveness of B.punctiventris reprodation during many years cycle of population dynamics. It was proved that toxication of the sprouts by means of preliminary seed dressing for last years exerted essential influence on a structure of population of phytophagoes in the sugar beet agrocenosis in the period seeds' germination - two pairs of leaves. There were developed algorhythms and mathematical model of population density of B.punctiventris and T.palliatus for the computer forecasting. Results - the results of the researches areused for more accurate definition of the zonal protection systems of the sugar beet from B.punctiventris and T. palliatus in different conditions for sugar beet growing in the farms with diverse forms of property and also by the State Servise of Forecasts and agricultural educational institutions. Field - agriculture, forecast.