Here is an interesting article I read on roaches:
Roaches will eat just about anything when hungry enough but their preferred diet consists of carbohydrate based substances including pastes, glues, solid soaps and starch based paints and foods like pasta. The following tips and methods may be tried on any of these roaches.
Sugar and Baking Soda: This excellent cockroach treatment comes from Christopher Moss who resides in Prescott, Arizona. He says this worked on the smaller Oriental type of cockroaches that tend to infest cabinets. Prior to coming up with this recipe Christopher had used the commercial type sprays that you can find at supermarkets to no avail. Boric acid bates did not work either. Our many thanks to Christopher for this!
Here it is. Just mix 50/50 granulated sugar and baking soda (Arm & Hammer will do) and place it in their path. Takes about 3 or 4 days to notice a reduction and 2 weeks later, no roaches. The cure seems relatively permanent, although you may have to repeat some months later.
Why might this work?
The roach has an acid stomach. They can't resist the sugar and the baking soda mixes with the acid in their stomachs. Blamo! The best part is the roach is a cannibal and they eat their dead, and the whole process cascades through the colony