Treatment of Kretzschmaria deusta (brittle cinder fungus) with Trichoderma Spore Solution

Trichoderma spp. are known for their ability to secrete cell wall-decomposing enzymes, enabling them to parasitize harmful fungi. Also, the growth of Trichoderma is fast in comparison to harmful fungi, making Trichoderma highly competitive in terms of space and food, so pathogens can be easily suppressed. Classified as a surface mould, many studies also demonstrate the effectiveness of Trichoderma on leaves and stems. Trichoderma spp. are playing an increasingly important role worldwide as a bio-control agent, replacing environmentally-damaging fungi that may also promote a serious health risk.

The following is an example of a beech infected with Kretzschmaria deusta. Kretzschmaria develops in spring between March and May. The fruiting bodies in early spring are wavy-edged cushions or crusts and are white-grey in colour. In summer, the fruiting bodies turn black, becoming extremely brittle (hence the common name, brittle cinder).

Kretzschmaria is often overlooked due to the inconspicuous nature of the fruiting bodies occurring at or below the stem base, especially during the initial stages of development. This wood-decay fungus can reduce the breaking resistance of the affected tree to varying degrees depending on the tree species, and the vitality and resistance of the tree at the time of infection (trees with higher resistance include: beech, lime, maple, plane, hornbeam and oak, while trees with lower resistance include: horse chestnut, poplar, ash, birch). The fungus usually colonises the tree via injuries around the roots or stem bases. There it causes a mould rot in the wood. If the disease lasts longer, the fungus can spread higher up the trunk (e.g. forking).

The beech treated in this example has been infected for about 8 years. Only two years ago the owner noticed the fungus and contacted an arborist who immediately started the treatment using the bio-control, Trichoderma. Upon the 3rd year of the treatment no new fruiting bodies were evident, and therefore no extended legions, while the older fragile crust fell away from the trunk.

The development of Kretzschmaria can be measured by a reduction in stability. For this beech the annual tensile tests proved positive. In addition to the tensile tests, the internal decomposition of the wood will be recorded using a PICUS sonic tomograph. The tree can compensate with wood growth in the relevant areas along the lower trunk area. The loss of vitality is acceptable for the owner and his wish is to keep the old beech in his park garden as long as possible. The loss of vitality is indicated by the thinner and lighter canopy of the tree, which consequently also reduces the strain on the trunk.

Annual treatment with Trichoderma atrobrunneum (formerly harzianum) 1×108 KBE/ml:

– Spraying the fruiting body with liquid solution (30-100 ml spore solution diluted with 1 L water) in dry weather conditions below 30 °C, several times a year.

– Watering of and around the roots within the shaded area underneath the crown with water spore solution (2-10 ml per L water, 1 L water per 1 m²), several times a year in humid soil conditions.

Spray the spore solution diluted with water directly onto the fruiting body (recommended dosage 30-100 ml to 1 L water, application several times a year under dry conditions below 30 °C).

Watering the spore solution diluted with water (2-10 ml to 1 L water, 1 L to 1 m²), several times a year in humid soil conditions.