Since BRR disease causes root rot at the lower trunk above grade level (e.g. it could be observed up to 2 m in some tree species) and/or root collar and/or roots at the sub-soil level, it is essential to evaluate the thickness of sound wood of the tree at horizontal plane at critical levels (i.e. […]
Yes, early diagnostic symptoms of BRR disease are often difficult to detect, despite the fact that the disease can cause a rapid decline in tree growth conditions within a short time. More often than not, obvious symptoms will only be visible at a late stage of infection. Once symptoms such as abnormal crown symptoms (e.g. […]
Yes, root excavation with appropriate tools (e.g. handheld adze, digger, air spade, etc.) may be required to expose the root collar and roots. The exposed root collar and roots could subsequently be examined for the typical signs of BRR disease. Scraping off of bark tissue should only be conducted on decayed, damaged or dead wood/roots. […]
The typical signs of BRR disease are a) fruiting bodies of Phellinus noxius, b) mycelial encrustation, c) soil aggregates and d) mycelial nets. (a) The appearance, on lower trunk or roots, of brownish-black/dark greyish-brown colored imbricate or resupinate fruiting bodies of Phellinus noxius with their characteristic porous hymenium surface up-facing is an obvious sign of […]
No, the abnormal crown symptoms are commonly associated with root diseases and malfunctions, and are not unique to BRR disease. Thus, it is important to further examine the lower trunk, root collar and roots for typical signs of BRR disease.
Symptoms of the disease are of two types, namely slow decline and rapid decline. For trees experiencing slow decline, the most noticeable symptoms may include crown thinning out gradually and turning yellowish and their leaves reduced in size or even dropped as a result of early senescence. The trees could be dead in months or […]
Field diagnosis through visual tree assessment is based on observable symptoms and signs of BRR. There are two steps. Step 1: Identify abnormal crown symptoms (e.g. sparse foliage density, abnormal foliage colour (chlorosis), abnormal leaf size, dieback twigs) as these are exhibited in infected trees. Step 2: examine the entire lower trunk, root collar and […]
There are currently two main levels of diagnostic methods available for determination of BRR disease in trees, namely field diagnosis through visual tree assessment and laboratory diagnosis through fungal isolation method and/or molecular diagnosis.
According to literatures and expert opinion, there is yet to be an effective cure for BRR disease.
The disease is prevalent in tropical and subtropical regions in different part of the world and has been found in Asian countries & regions such as Japan, Mainland China, Hong Kong, Taiwan, Malaysia, Singapore as well as Central America, Africa and Oceania.
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