how to kill hookworm in grass

Honestly I know of absolutely NOTHING that will kill hooks (or whips) in lawn.  My vet replaces his sod periodically for that exact reason. 

Once you have them, it's MY understanding (and there may be something out there I'm not aware of) you simply have to watch *constantly* (as in fecals several times a year) or use a product like Interceptor (a heartworm preventive that is dosed stronger than HeartGuard simply because it is far far better tolerated by most dogs -- it will kill hooks and whips) on a monthly basis pretty much year round.

It's my understanding hooks and whips can survive most winters anywhere - they simply go dormant when it's cold and then 'revive' when the weather conditions are optimum for them.  I've used Interceptor for years because MY yard got polluted with hooks/whips one year when we took a foster during a hurricane down here in Florida *sigh*.

My research yielded the same results as Callie's.  You'd have to shovel up the area where the dog pooped, each time.  The only thing that kills eggs is drying, which isn't all that likely.  My dog's are now on Interceptor, and they have fecals at least once a year since it's required by our training club.