Mikhail A. CHUMAKOV¹ and Igor V. SUKHANOV^2
1Ml-Russian Institute for Plant Protection, av. Podbelskogo 3, St. Petersburg, Pushkin, 189620 Russia;
²Nizhny Novgorod Agricultural Academy, pr. Gagharina 97, Nizhny Novgorod,603097 Russia;

In the north part of distribution area (Belgorod Province) of the European corn borer [ECB], Ostrinia nubilalis Hbn., where phytophagan gives one generation per season, investigations on its population dynamics were conducted during 1994-1998. The main goal of this work -quantitatively estimate the role of biotic, abiotic and anthropogenic factors in population dynamics of the ECB by means of life tables. The data obtained indicate that the pest mortality owing to entomophagous (primarily larval parasitoids Lydella thompsoni and Enborus terebrans) was slight (within 9-24%) therewith egg parasitism by Trichogramma evanescens was at a level 0-2%. Larval death caused by pathogenic rnicroorganisms lay in a range 2-11%. Maize harvesting led to 18% decrease of diapausing larval population in average between years. Population dynamics of the insect for the most part depend on the process of egg realization by females (73-95% mortality at K  0.57-1.34) and also on the lst-2nd instar larval capability for plant survival (62-79% mortality at K  0.42-0.69). K-factor analysis allowed to draw the following conclusion: time interval of mating and egg -laying by females can be considered one of the main critical periods in phytophagan life cycle and female ability for egg realization must be taken as key factor of the ECB population dynamics in this zone of Russia.

Acknowledgments: This work has been done by the financial support of RFBR grants # 94-04-11328 and # 97-04-48015.