Identify two types of treatments used for drywood termites.

The correct answer highlights two effective methods used specifically for treating drywood termites. Fumigation is a comprehensive treatment that involves enclosing a structure in a tent and introducing a pesticide gas that penetrates all wood components. This method is particularly effective for drywood termites because they can infest within the wood, making localized treatments insufficient for complete eradication.

Localized treatment with targeted insecticides is another approach that involves applying insecticides directly to areas where termites are present or where they have been detected. This method can effectively control smaller infestations when they are identified early. Together, these treatments provide a strong strategy for addressing drywood termite infestations.

The other options do not adequately address the treatment of drywood termites. Boiling water and natural repellents may work in some contexts but are generally not effective against established infestations. Soil barriers and bait systems are more appropriate for subterranean termites, not drywood termites, as these treatments target different types of termite behavior and habitat. Sealing cracks and using pesticides can help prevent various pests but do not specifically target drywood termites or provide a means of eradicating an existing infestation.