To deal with ants entering your house, you can use several types of pesticides and methods to prevent them from coming through the walls:

1. Bait Stations: These contain a slow-acting poison mixed with an attractant. Ants take the bait back to their colony, which eventually kills the colony. Place these near entry points and where you see ants.

2. Sprays: Insecticide sprays can kill ants on contact and create a barrier to prevent them from entering. Look for sprays containing ingredients like deltamethrin, bifenthrin, or permethrin.

3. Granules: These can be spread around the perimeter of your home. The ants carry the granules back to their nest, affecting the colony.

4. Diatomaceous Earth: A natural, non-toxic option. It’s a powder that can be spread around entry points. It kills ants by dehydrating them.

5. Ant Dust: Products like those containing permethrin or deltamethrin can be dusted into cracks and crevices where ants enter.

6. Gel Baits: These can be applied in cracks and crevices where ants are seen. Ants consume the gel and take it back to the colony.

Preventive Measures:

• Seal Entry Points: Use caulk to seal cracks and crevices in walls, around windows, and doors.
• Remove Food Sources: Keep your house clean, store food in airtight containers, and promptly clean up spills.
• Trim Vegetation: Keep plants and trees trimmed away from the house, as ants often use these as bridges to enter homes.
• Use Ant Barriers: Products like Tanglefoot can be applied around the base of the house or on trees and plants near the house.

Safety Tips:

• Always follow the instructions on the pesticide label.
• Keep pesticides away from children and pets.
• Consider non-toxic options if you have pets or small children.

If the infestation is severe, it might be best to contact a professional pest control service.