i use olive oil and it is awesome. it stops B. germanica so i imagine it would stop P. niveaYou can use olive oil, in Spain is very common and cheaper than vaseline, and better.
If you don´t have olive oil, put vaseline and pray .
Good luck with them!
i'm not sure if that would work. glasswalking roaches have scopulae... patches of molecularily adhesive super fine hairs that adhere to anything. crickets lack these scopulae. essentially crickets climb smooth surfaces by finding dirt and/or imperfections to hook their feet into. glasswalker roaches can, well, walk on glass. olive oil works as a barrier because a superfine layer of the oil adheres to the scopulae and then lifts off the wall. the bugs eventually could wear away the oil... but if you renew it every couple months then no worriesI don't know if it will work for roaches, but I use a product called aluminum tape (or duct tape - but not the Red Green kind ). I buy it at the local big box hardware stores (like Home Depot). I have used it for 10+ years for my cricket that are in Rubbermaid containers and have never seen a cricket get passed it. It is 2" wide and has a peel off layer on the back. I put it about 3" from the top of the container and even if the crickets can climb up the Rubbermaid, they are not able to get past the tape.
Like I said, I have never used the tape for roaches (I only have discoids) but it works like a charm for the crickets. Hope this helps.
Like me .i personally have a little 4oz (er... a small fraction of a liter, heh) tupperware that i keep a few ounces of oil in. i paint a 3-4" (8-10cm) band around the top of the roach container every couple months. to retouch sometimes i just get a bit of papertowel or my fingers and smear a few drops over the old barrier.
there are these discount type stores that sell things for 99 cents ($0.99) or $1. i bought mine there, i believe. or i stole it from my old kitchen... don't remember. at the dollar store you can usually get 4L of olive oil for $1Like me .
A question for cacoseraph: Where do you buy olive oil in the U.S.? How much is it? I´m curious