Direct Effects of Carpophagous Insects on the Germination Ability and Early Abscission of Oak Acorns

• Main Authors: CSÓKA, György, HIRKA, Anikó
• Format: Article
• Language: English
• Published: Sciendo 2006-01-01
• Series: Acta Silvatica & Lignaria Hungarica
• Subjects: oaks; Quercus; acorn; carpophagous insects; germination ability; early abscission
• Online Access: http://aslh.nyme.hu/fileadmin/dokumentumok/fmk/acta_silvatica/cikkek/Vol02-2006/csoka-hirka.pdf

Carpophagous insects play an important role in decreasing the viability of acorns in bothdirect and indirect ways. Therefore they significantly influence the reproductive potential of oaks. As adirect effect, their feeding on the embryo and on the cotyledons may prevent the germination of theacorn and on the other hand, their damage causes premature acorn abscission. During 3 years, 60acorn samples from five oak species (Turkey oak – Quercus cerris, pedunculate oak – Quercus robur,sessile oak – Quercus petraea, downy oak – Quercus pubescens, red oak – Quercus rubra) have beeninvestigated. The average rate of damage varied a lot between years, but was always significant (2000:36%, 2001: 61%, 2002: 51%). The insects’ influence causing premature acorn abscission wassignificant both for pedunculate and Turkey oaks. The premature acorn abscission was 34% of thetotal crop in 2000 for pedunculate oak (Curculio spp. 26%, Cydia spp. 2% and Andricusquercuscalicis 6%) and 39% in 2001 (Curculio spp. 14%, Cydia spp. 2%, Andricus quercuscalicis13%, Callirhytis glandium 10%). In case of Turkey oak it was 29% in 2001 (C. glandium 16%,Neuroterus saliens 13%, and 12% in 2002 (C. glandium 10%, N. saliens 2%).