Lyctid beetles primarily infest which type and age of wood?

Lyctid beetles are known to target hardwood, particularly favoring newly cut or freshly processed wood. Their larvae, which are the life stage that causes damage, thrive on the starch in the wood, which is more prevalent in newer wood. While they can also infest older hardwood, it is mainly the new wood that provides the ideal environment for their development. This preference makes new hardwood the primary target, illustrating why this answer is chosen.

The mention of "occasionally old hardwood" indicates that while they can infest older wood, it is significantly less common than their infestation of new wood. In contrast, new softwood is not a habitat of choice for lyctid beetles, as they specifically seek out hardwoods for their life cycle. Thus, the emphasis on both new and occasionally old hardwood in the correct response accurately reflects the specific conditions under which lyctid beetles thrive.