I can't rototill an 4'x8' bed but if I had mustard plants I can chop it and bury it. I found this one:
http://www.groworganic.com/mustard-nemfix-lb.html
but it says
cool season. I think it's too late to do this because I am in Southern California, cool season plants are bolting. What about milkweed, they also have glycosids?