Population fluctuation and biology of oak moth, Porthesia melania Stgr. (Lep., Lymantriidae)

Porthesia melania Stgr. (Lep., Lymantriidae) is the most important pest of oak trees inKermanshah province iran and its larvae feed on upper surface of oak leaves. The population fluctuations of larvae were investigated weekly in the region, from March 2008 until April 2009. The highest and lowest densities of larvae were observed in the late March and mid May, respectively. During summer and winter, no larvae were observed on oak leaves. The third larval stage which lasted eight months from the late July until mid March in diapauses form, was the longest life stage of the oak moth. The pupae were formed in the soil. The adults emerged gradually during 37 days in the nature. The peak of adult emergence was on 23 May. The egg hatch was started from 5 May. Female moths lay 60-140 eggs on the oak leaves. The latest eggs hatched in mid June. Investigation on biology of oak moth revealed that this pest had one generation in a year in Miandar region and overwintered as the third instar larvae.