Original soil rescues tree cancer: The Forest Research Institute develops a multi-microbial preparation to control brown root rot

Brown root rot disease is one of the common tree diseases in Taiwan, China. According to statistics from the Tree Medicine Center of the Taiwan Forestry Research Institute (hereinafter referred to as the "Forestry Research Institute") under the Council of Agriculture, among the cases reported over the years, nearly 40% of the pest and disease cases were brown root rot disease, causing large numbers of trees to die. To strengthen disease management, the Forestry Research Institute held the "2017 Symposium on the Prevention and Management of Brown Root Rot Disease in Trees," introducing treatment methods and rapid detection technology for brown root rot disease. In addition to traditional chemical treatments, the Forestry Research Institute has developed biological agents with antibacterial effects in recent years, including compound agents of actinomycetes, lactic acid bacteria, photosynthetic bacteria, and other microorganisms, which are environmentally friendly and also effectively reduce the proportion of pathogens in trees affected in the early stages.

"Tree cancer" brown root rot disease: from banyan trees to beefwood, none can escape large-scale infection

Brown root rot disease, commonly known as tree cancer, is caused by the brown root rot fungus (Phellinus noxius) infecting the roots of trees, the phloem and cambium of the stem base, and surrounding woody parts, damaging the plant root system. The brown root rot fungus thrives at 25°C in high-temperature, high-humidity environments. It is contagious and can spread over long distances through spores, but in Taiwan it mainly spreads through contact infection via plant wounds. At present, more than a hundred species of plants in Taiwan are hosts of this fungus, including the banyan trees commonly seen in cities and the beefwood trees along the coast, and if not treated early it can cause large-scale infection.

After infection, a yellowish-brown mycelial mat can be seen on the surface of the tree roots, and the wood tissue shows a yellowish-brown network pattern. Section Chief Hsiao Chi-hui of the Forestry Bureau pointed out, "After the roots are damaged, water absorption is affected, the leaves turn yellow and smaller, the branches and foliage gradually become sparser, the root tissue rots and dries up, and the overall growth vigor declines. In the end, the tree loses its support and topples in the wind." This poses a certain degree of risk to public safety.