Canadian Nematodes - As much fun as a pack of sea monkeys
That's right kids, they're tiny, but they can be an organic effective pest-control of some grass killing bugs.
It looks like I have grubs eating the roots of my grass, I had mistakenly thought it was fungus damage before, but my neighbour has grubs, so I'm going to go with Occam's Razor and suspect that I have the same cause of the same problem since we're in the same area.
I bought Lawn Guardian from NIC which contains 10 million (various package sizes available from 1 million up) nematodes. In particular the little critters are J3 stage Steinernema carpocapsae and Heterorhabditis bacteriophora.
So hopefully I will get my lawn back. Having a mini-desert (root-less grass doesn't like dry weather) is not fun.