Hi Daniel,

Based on your question, I think you're mainly asking if Zoysia grass is a good option for a lawn in Springfield, VT rather than diagnosing why the existing grass has gone brown.

I'm going to include a resource on white grub lawn damage just in case it's helpful to you.

https://www.uvm.edu/~entlab/Landscape%20IPM/WhitegrubsinsoilJune2023.pdf

and one about diagnosing lawn issues

https://ag.umass.edu/turf/fact-sheets/whats-wrong-with-my-lawn

Now about Zoysiagrass:

It is commonly used as a turf grass because of it's density, leaf structure, and diversity. https://aggieturf.tamu.edu/texas-turfgrasses/zoysiagrass/  That said, it is a warm-season grass so I don't think it would survive long up here.  The ideal climate zones are 6-11 and Vermont ranges from 3-5b.

Here is a resource that gives some information about grass seed types and mixture recommendations for our region that I think you'll have better success with in repairing the lawn you're dealing with.  https://www.uvm.edu/sites/default/files/Extension-Master-Gardener/LAWNRENOEST.pdf

If there is any other way I can assist you please feel free to reach out again.

Best,