When they infest a home, cockroaches like to congregate and lay their eggs in secluded spots near sources of food and water. They hide in cracks and crevices, inside cabinets and under sinks, but sometimes their hiding places are under, behind or inside appliances.
Before you can effectively get rid of cockroaches, you first have to find out where they are. If you suspect that roaches are living in or near an appliance, look in the vicinity for live roaches, dead roaches or shed skins. Also look for droppings, which look like grains of black pepper or coffee grounds, and egg cases, which are brown, about 1/4 inch long and rectangular or oval in shape. Look for these signs under, behind and inside the appliance, using a flashlight and, if necessary, a small mirror.
Roaches can't tolerate extremely cold temperatures, so one of the most effective ways to deal with them when they've infested small appliances is to kill them with cold. Put small appliances, such as toasters, in a sealed plastic bag and place them in the freezer. During the winter in cold climates, larger appliances, such as microwaves can be placed outside as long as the temperature is below 20 degrees Fahrenheit.
If you're able to move large infested appliances such as refrigerators, dishwashers or ovens to an unheated garage our outbuilding during cold weather, cold treatment is an option for these large appliances, as well.
Extreme cold will likely kill roaches within several hours, but leaving the appliances in the cold for several days will ensure that all the roaches inside are dead. Clean the appliances thoroughly inside and out before bringing them back into the house. While the appliance is outside, conduct full pest control in the kitchen or roaches will move right back in to the reintroduced appliances.
Sticky traps are a non-toxic control method that can be used safely in places that toxic methods should be avoided, such as in food preparation areas or where children or pets play. However, sticky traps usually don't kill enough roaches to entirely clear infestations, so they're best used in conjunction with other control methods.
Cockroach Dusts and Baits
If cold treatment isn't an option, you may need to use insecticidal control methods to kill roaches near appliances.
Cockroach baits contain roach-killing compounds such as hydramethylnon, boric acid, sulfluramid or fipronil. The roaches carry the compounds back to their hiding places where they will kill other adults and juvenile roaches. Place the baits in the locations near appliances where you've identified signs of roach activity, placing them in corners and against walls.
Cockroach dusts usually contain silica, diatomaceous earth or boric acid. Scatter the dust in a very thin layer behind and under appliances where roaches are active. These products are relatively safe but should only be applied where children or pets won't be exposed to them.