Germination success, survival and seedling vigour of Quercus suber acorns in relation to insect damage

This study assesses the effects of damage caused by Curculio elephas Gyll. (Coleoptera: Curculionidae) and Cydia splendana Hb. (Lepidoptera: Tortricidae) on mature acorns of cork oak trees, Quercus suber L., in Portugal. The average number of insect-attacked acorns varied between 68, 44 and 17%, in three sites, respectively. Acorns assorted into increasing damage classes had a decreasing acorn dry weight and a faster germination rate. The percentage of germination was very high (>90%) in all classes. Seedlings resulting from more intensely damaged acorns exhibited a slower growth rate and lower dry mass production than seedlings resulting from low damaged acorns.