Canadian Forest Service Publications

Biological control trials of beech bark disease under laboratory conditions. 2009. Laflamme, G.; Boudreault, S.; Lavallée, R.; Blais, M.; Blanchette, J.-Y. SDU Faculty of Forestry J. Serial A: 194-199.

Year: 2009

Issued by: Laurentian Forestry Centre

Catalog ID: 31068

Language: English

Availability: PDF (request by e-mail)

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Beech bark disease (BBD) causes mortality of American beech (Fagus grandifolia Ehrh.). BBD involves an attack by the beech scale insect Cryptococcus fagisuga Lind. followed by the native fungal pathogen Neonectria faginata (Lohman et al.) Cast. & Rossman. C. fagisuga was introduced into Halifax, Nova Scotia, from Europe through seedlings around 1890. Damage to American beech was observed 20 years later. Our objective is to use entomogenous fungi to control the insect. Lecanicillium muscarium (Petch) Zare & W. Gams, common in European infested sites, was retained as well as Beauveria bassiana (Bals.-Criv.) Vuill. Our first trials were done on non-crawling nymphal stage on bark disks, 24 mm in diameter, kept individually in Solo cups® at 20°C or 25°C. To expose the insects, the “wool-like” wax covering the colony was removed. The treatment consisted of an application of 125 μL of 106 spores/mL of water and oil. A second trial was conducted by spraying spore suspensions of L. muscarium (100 μL) on eggs kept at 25°C. Both biological control agents reduced the crawlers’ population by 50% after 11 days. Eggs treated with L. muscarium showed low mortality, but their development was slowed down. Fungi seen on the surface of the eggs invaded the first instars. Field trials are underway.