Q. I ran across an item called Grub Guard in the catalog. It contains beneficial nematodes. Would these be the same kind of nematodes that attacked my tomatoes last year?  A. These are entirely different nematodes. These are good guys and pose no problems to other plants. The ones that attacked your tomatoes are probably root knot nematodes which are never good, always bad guys. You are safe to use beneficial nematodes in your landscape.