This pesticide works excellent for cockroaches.
250g Boric acid (H³BO³) in powder-form - don't confuse with borax (Na²BO-10H²O)
200 g fresh onion pulp
20g Starch powder
25g (5 e) milk powder
Mix all the ingredients in a mixing bowl. Spread an old newspaper and put wet mixture on it. Leave it overnight. Form fingernail-size balls of the paste and put it all over the place which is targeted by the pests. Please note that the boric acid may be harmful for pregnant woman.