What can ants not walk on?

Ants have difficulty walking on several surfaces that are sticky, slippery, powdery, or extremely hot, which can be used as temporary barriers, though persistent ants will often find ways around if food is attractive enough and no barrier is 100 percent effective against all species. Ants cannot walk easily on sticky surfaces such as petroleum jelly, Vaseline, Tanglefoot, or other horticultural sticky barriers applied around table legs, cords, or entry points, because their legs get stuck and they avoid crossing. They have difficulty walking on very slippery surfaces coated with talcum powder, baby powder, or fluon which is a liquid that dries slippery and is used in ant farms to prevent escape, because their adhesive pads cannot grip. Powdery surfaces like diatomaceous earth, which dehydrates insects, and loose cinnamon, black pepper, or cayenne pepper can irritate and make walking difficult, though ants may cross if trail is broken. Ants cannot walk on water and will avoid crossing water moats, which is why placing pet food bowls in shallow water prevents ants from reaching them, though large numbers can form bridges with their bodies. Very hot surfaces above 120 degrees Fahrenheit deter them. Extremely smooth vertical glass can be difficult but many ants can climb it using adhesive pads. However, odorous house ants and carpenter ants are persistent and will often cross powder barriers if there is a gap, so most effective control is not relying on surfaces they cannot walk on alone, but integrated pest management including sanitation, sealing cracks with caulk, and using gel baits containing fipronil or borax that workers carry back to kill queen and colony.