OPM Termite Practice Exam

Which type of wood destroying fungi is considered the most damaging?

1. White rot

2. Soft rot

3. Brown (dry rot)

4. Black rot

The correct answer is: Brown (dry rot)

Brown rot, commonly referred to as dry rot, is considered the most damaging type of wood-destroying fungi. This type of fungi primarily affects the cellulose in wood, leading to a rapid deterioration of structural integrity. Brown rot converts the cellulose into a brown powder, leaving behind the lignin, which causes the wood to turn brown and become brittle, giving it a characteristic dry appearance. The reason brown rot is particularly detrimental is that it can progress quickly and cause significant structural damage if left untreated. Unlike other types of rot, such as white rot, which affects both cellulose and lignin, brown rot has a more aggressive nature, often leading to more severe consequences for wooden structures. In contrast, white rot fungi can break down both cellulose and lignin, but they tend to do so more slowly and typically do not cause the same rapid loss of structural integrity. Soft rot is generally less harmful and mainly affects wood with a high moisture content. Black rot is also less common and often appears in specific conditions. Thus, brown rot stands out as the most destructive to wooden structures.