The population fluctuations of Euzophera bigella (Zeller) and Cydia pomonella (L.) at quince orchards

The lepidopterans Euzophera bigella (Zeller) (Pyralidae) and Cydia pomonella (L.) (Tortricidae) are the most important pests of quince trees in Iran, as they cause the qualitative and quantitative losses on quince fruits. The present study was performed to monitor the population fluctuations of E. bigella and L. pomonella using synthetic pheromone traps at quince orchards in Falavarjan (Isfahan, Iran). In addition, the influence of climatic factors on population fluctuations was studied. It was found that E. bigella adults appeared in early March, showing four population peaks during growth season. The adults of L. pomonella were, however, showed up in middle March with five seasonal population peaks. The populations of male E. bigella were positively correlated with relative humidity, weekly rainfall (up to 3.5 mm), weekly means of minimum andmaximum relative humidity and temperature (higher than 25 °C). In addition, when rainfall was 1.2 mm no significant effects of weekly means of minimum and maximum relative humidity and temperature were observed on E. bigella densities. The population densities of male E. bigella also showed a significant positive correlation (r = 0.58) with relative humidity.