“If you have a new colony of Formosan or Asian termites, you’ve got three to five years until they do substantial damage. It’s best to treat them immediately with the bait system,” Su says. That’s because colonies of these non-native termites are 10 times larger than native species, leaving exposed beams looking like shredded wheat. “With an established colony, you have 12 months before they eat through your roof trusses. Then, the weight of the roof ends up caving in.”