The effect of weevil and fungal attacks on the germination of Quercus robur acorns

Abstract

Oak, Quercus robur, acorns are sometines attacked by a weevil or infested by fungi ( Murray, 1974). The number of acorns produced varies greatly from year to year. Acorns produced in the years between mast years may escape these weevil or fungal attacks, be dispersed and germinate. Acorns were collected annually from 1983 to 1989 from five oak trees in southern Sweden. The percentage of acorns attacked by a weevil or fungi, or both, were monitored and the acorns' ability to germinate was tested. Not all acorns were damaged in low crop years; the proportion of undamaged acorns varied between 33 and 69%. The proportion of weevil-attacked acorns differed significantly between the years. The proportion of acorns that were able to germinate in each category did not vary significantly between years. The germination ability was significantly higher in undamaged or fungi-infested acorns.