S. Mahunka szerk.: Folia Entomologica Hungarica 33/2. (Budapest, 1980)
FOLIA XLI (XXXIII). 2. ENTOMOLOGICA HUNGARICA ROVARTANI KÖZLEMÉNYEK 1980 p. 23-32 The coefficient of population and its application in plant-protecting prognosis By I. EKK, M. KISS, L. NOWINSZKY, S. SZABÓ and G. TÓTH (Received June 15, 1979) Abstract: A new method to compare and study the data obtained by light-trap working at various localities has been elaborated. By introducing an easily definable factor, the "coefficient of population", the authors discovered some periodicities in the number of individuals of two deleterious moths. Owning to these laws, the authors are able to give with a high level of probability a long-term prognosis concerning gradation. The prognosis of the mass appearance of deleterious insects constitutes the basic task of modern plant protection. It is possible to prognosticate the well-flying insects attracted by light-trap, e.g. moths, by data processing of catches. The light-trap gives us information on the mass and location of swarming. In addition, it is a reliable tool to study gradation. Unfortunately, the catching data of light-traps of various locations cannot be compared with one another by direct methods. The influencing factors associated with the physical characteristics of the light-trap and the physiological factors determining the flight of Insects into light were the same but, the plantstock of the environment was differing from another as were the meteorological parameters, furthermore they were modulated by the periodically variable moonlight or by the natural illumination of the environment. In need of a suitable comparison between the catching results to obtain each phase of a hypercycle in space and time, and to obtain a law of population dynamics, many methods are used by research workers. KOVÁCS and DELY (1967) took into account only arithmetical means of past years as a comparison. BENEDEK and JÁSZAI used the so-called 'museum method' (SOOS, 1958) since they believe such a procedure eliminates the deforming effects caused by wheather neglecting the number of individuals (JÁSZAI and BENEDEK, 1968; BENEDEK and JÁSZAI, 1969). WÉBER (1959) wrote that the 'museum method' does give us an accurate picture about the swarming. In practice, the methods of WILLIAMS (1935,1939 and 1940) did not come into general use, he worked with the logarithm (of the base ten) of the number fo individuals to compare the daily and monthly catches for a given light-trap. Williams thought to eliminate the deforming influence of various catches due to extreme meteorological circumstances. Nowadays indirect methods are used in order to compare the results, for this purpose one can consider the coefficient of generation or/and the coefficient of reproduction (MÉSZÁROS, 1963, 1964a, b, 1965,1068, 1969), (MÉSZÁROS and VOJNITS, 1968). Fortunately, both the abovementioned coefficients indicate the tendency of variation in mass, however, are suitable to make some prognosis, though unsuitable to signalize mass of population. The coefficient of population (NOWINSZKY, SZABÓ and KISS, 1978) gives an information on the mass of the population, too. The coefficient of population (P) is defined as a quotient of catching at any time (N) (e.g. the number of individuals to be caught during a swarming) and of the geometrical mean of the whole catching (x g ):
