CA BRANCH 3 Structural Pest Control Exam Marking Scheme

CA BRANCH 3 Structural Pest Control Exam Marking Scheme How can you tell the difference between wood suffering from brown rot and wood suffering from white rot? - ANSWER- Wood infested with brown rot typically: • appears dark brown, • shows excessive shrinkage, • develops cross-grain cracking, and • can be crushed easily to form a brownish powder. Wood infested with white rot on the other hand, often: • appears whiter than normal, • shows normal shrinkage, • does not crack across the grain, • is spongy to the touch. What is the difference between the stains caused by stain (sapstain) fungi vs. mold fungi? - ANSWER- Sapstain fungi live on the starch in wood cells. These fungi may discolor the sapwood entirely or in patches. This stain is deep within the wood and cannot be removed by brushing or planing. On the other hand, discoloration caused by mold fungi is superficial. This means that you can usually remove the discoloration by brushing or planing. However, on hardwoods with open pores (very large and visible vessels) such as the oaks, the surface molds may cause stains that are too deep to remove easily. How can you distinguish between winged termites and winged ants? - ANSWER- Look at their antennae, waists, and wings. Winged termites have straight antennae, thick waists, and wings that are equal in size and shape. Winged ants have bent antennae, narrow waists, and forewings that are larger than the hind wings. Name the four basic castes of termites. Describe the basic function(s) of each caste. - ANSWER- Workers - gather food, maintain the galleries, tend the young, and groom the other termites. Soldiers - guard the colony against predators. Primary reproductives - "swarmers" that fly out of their colonies to start new colonies of their own. They are the future kinds and queens of new colonies. Secondary reproductives - supplement egg production in the presence of the king and queen and can take over the egg laying if the queen dies or begins to fail. Do subterranean termites live entirely within wood? Why or why not? - ANSWER- No, because they require a constant source of moisture to survive. However, they can live in wood with less than 20% moisture by getting their moisture from the ground. They transport this moisture through flattened, earthen shelter tubes that serve as passageways from the soil to the infested wood. How do subterranean termites most often infest wood in buildings? - ANSWER- They gain entry through untreated wood that touches or is close to the ground, particularly at porches, steps, and terraces. They can also infest buildings through cracks or voids in foundations or concrete floors that make it easy for termites to reach wood that is not close to the soil. Describe the frass pellets of drywood termites. - ANSWER- They are small and cylindrical with six depressions on the sides. These pellets are unique to drywood termites and are used for identification. Where do drywood termites most often occur? - ANSWER- In southern Florida, southern California, and along the southern gulf coast of the United States. Do drywood termites live entirely within wood? Why or why not? - ANSWER- Yes, because they require little moisture (wood MCs as low as 5%). Unlike subterranean termites, drywood termites have no connection with the soil. List several ways you can protect wood from termites. - ANSWER- To protect wood from subterranean termites, you can: • apply insecticides to the soil around buildings, and • avoid using wood mulches next to buildings. To protect wood from subterranean and drywood termites, you can: • use physical barriers on foundations, and • use properly preserved wood, which makes it undesirable as a food source.