Biological control of chestnut ink disease with ectomycorrhizal fungi

BRANZANTI, M. BARBARA¹_, ELISABETTA ROCCA² & ANNAMARIA PISI³.

¹ Dipartimento di Biotecnologie Agrarie ed Ambientali, V. Brecce Bianche, Ancona 60131, ITALY. ² Dipartimento di Protezione e Valorizzazione AgroAlimentare, V. Filippo Re 8, 20126 Bologna, ITALY. ³ Istituto di Patologia Vegetale V. Filippo Re 8, 20126 Bologna, ITALY.

Studies have shown that the ectomycorrhizal (ECM) fungi Laccaria laccata (Scop. Ex Fr.) Bk., Hebeloma crustuliniforme ( Bull. ex Fr.) QuËl, Hebeloma sinapizans (Paulet ex Fr.) and Paxillus involutus (Batsch) Fr. which are capable of forming ectomycorrhizae with chestnut in greenhouse experiments exhibit antagonistic capacity against Phytophthora cambivora (Petri) Buism. in paired cultures on agar plates. The aim of the present study was to investigate if an early infection by mycorrhizal fungi might protect Castanea sativa Mill.seedlings against attacks of ink disease. At the end of the first vegetative season mycorrhizal and non-mycorrhizal seedling were challenged with a zoospore suspension of P. cambivora. The interactions of the ECM fungi and the pathogenic fungus were studied using the light microscope and the scanning electron microscope. All the fungi tested had a protective effect against ink disease. In mycorrhizal plants no sign of infection of P. cambivora was observed; rare zoospores not germinated were present in non-mycorrhizal segments only.

Key words: Laccaria laccata, Hebeloma crustuliniforme, Hebeloma sinapizans, Paxillus involutus, Phytophthora cambivora.