If you plan on waiting until the infestation is gone before using the dishwasher again then you can powder it with insecticide dust and lay down gel bait and more dust behind it near the motor. This will be very effective in killing the cockroaches. You will want to run a final watch on empty and clear out any food in it very well. The insecticide dust is not dangerous to mammals so its safe to dust the dishwasher. You can also try putting dust and gel bait in other areas of the kitchen, behind the fridge and in the cabinets. Make sure to store all your food in glass or metal containers with a tight-fitting lid and get rid of any garbage right away. Do not leave dishes in the sink overnight and dry them off the sink after each use. Remember that any food a cockroach has accessed is not inedible. You can get a very serious stomach problem from eating the food so do not leave any food out on the counters or the table. Put it back in the fridge or through it in the garbage and then take the garbage out right away to limit their access to food. This will make the gel bait less effective.
Cockroaches are a very dangerous infestation and can make people very sick. As cockroaches moult, they lose pieces of their carapace as they grow a larger fresh one. Because they live in sewers this moulting will be coated in deadly bacteria like staph and human feces. This can be easily inhaled and cause lung infections, especially for people who already have breathing issues like asthma or cancer. For this reason, you will want to get rid of the cockroaches as quickly as possible. The fastest way to do that is to get professional treatment from a licensed exterminator. Dealing with a cockroach infestation in your requires careful planning and strong measures. Do not be laxidazical as this could end in the infestation getting worse, not better. If you feel overwhelmed call in a professional and have them do the treatment. There are many species of cockroaches in north America including two that are native and two that are not. American cockroaches are native to North America and so are Brown Banded cockroaches. Both of them live for six months to a year and can produce a few hundred eggs in that time. This is not a massive infestation and is something you can handle with domestic treatments. Another species that does not lay as many eggs is the oriental cockroach which is from Asia and is not great with cold temperatures which is why they must infest homes or die from North American winters. They can also be handled by domestic treatment but you have to act fast as they are more pernicious and difficult to kill than native cockroaches. The fourth species is completely different from the prior three. They are German cockroaches and they live shorter lives and can lay thousands of eggs in that time. While most cockroaches can lay five or six eggs at a time the German cockroach can lay as many as sixty. This is an infestation that needs to be treated by a professional as dust and gell bait will not be effective on this species.