Effects of hot water treatment, biocontrol agents, disinfectants and a fungicide on storability of English oak acorns and control of the pathogen, Ciboria batschiana
Eight biological control agents (BCAs; Clonostachys rosea, Trichoderma harzianum, Trichoderma polysporum, Phlebiopsis gigantea, Bacillus subtilis, Pseudomonas chlororaphis, Streptomyces griseoviridis), five disinfectants and a fungicide ( Prochloras-ManganTM) were evaluated for the control of harmful mycoflora on Ciboria batschiana-infected English oak (Quercus robur) acorns during storage at −1°C. All treatments were tested on both hot water-treated (HW) and untreated acorns. HW-treated acorns generally stored better than untreated acorns as a result of elimination of C. batschiana. The HW treatment increased the germination percentage before storage from 60 to 85%. Germination of HW-treated acorns decreased from 85 to 40% after 16.5 months of storage, whereas germination of untreated acorns decreased from 60 to 20% after a similar time. Ciboria batschiana infection of untreated acorns increased from 14% before storage to 55% after 16 months of storage. All disinfectants and BCAs had a positive effect on viability and particularly on control of C. batschiana in untreated acorns. Best control of C. batschiana occurred with C. rosea, MycostopTM (S. griseoviridis), Binab TFTM (T. polysporum + T. harzianum), and P. chlororaphis. For HW-treated acorns, there was only a small effect of BCAs on acorn viability while the fungicide and the disinfectants had no effect. Treatments also affected the saprophytic mycoflora with the HW treatment reducing the frequency of Cladosporium spp. and Papulaspora spp., but enhancing Alternaria spp., Mucoraceae and Penicillium spp. However, when combined with HW treatment, several BCAs significantly reduced the prevalence of these fungi. Also, C. rosea reduced the growth of Fusarium spp. Significant negative correlations (p < 0.001) were found between acorn germination and certain storage fungi such as Acremoniella atra, Cladosporium spp. and dematiaceous mycelia.
Document Type: Research Article
Affiliations: 1: Plant Pathology Section, Department of Plant Biology, The Royal Veterinary and Agricultural University, Thorvaldsensvej 40, DK-1871 Frederiksberg C, Denmark. (for correspondence), Email: firstname.lastname@example.org 2: The State Forest Tree Improvement Station, The Danish Forest and Nature Agency, Humlebaek, Denmark
Publication date: 2004-02-01