External Factors Affecting the Pheromone Monitoring of the Spongy Moth

Abstract

The method of pheromone monitoring in the pest density management system has gained wide popularity due to its relative simplicity. The aim of the study was to analyze the degree of conformity between the results of pheromone monitoring and population density dynamics of the spongy moth (Lymantria dispar (L.)), as well as external factors affecting the results of pheromone monitoring. The pheromone monitoring was carried out in the area of the Trans-Ural moth population in the Sverdlovsk region, in two areas – the one with a high population density and periodic outbreaks and other one with a very low density and no periodic outbreaks over the last 10 years. Simultaneously with the pheromone monitoring, population density was monitored based on autumn counts of egg masses. The results of long-term pheromone monitoring of the spongy moth allow us to come to the following conclusions. The catching capacity of traps is mainly influenced by weather conditions, including air temperature and the stability of air currents during the males’ flight. The masses’ density and the reproduction rate of the spongy moth population can influence the results of pheromone monitoring, but they are not the decisive factors. It is possible to make predictions of changes in the population density of this species only with detailed pheromone monitoring with accurate recording of main males’ flight period, using correction factors that take into account weather conditions. However, the authors doubt the economic feasibility of this kind of measures for the purpose of assessing the pest’s population’s density and monitoring its dynamics.