Beneficial means good and safe.

Beneficial, good, safe, but adding them to seed is probably unnecessary. If you provide an environment they like ie. good, healthy soil, they will move in and do their thing without being on seed, or any need to spend your money on them. The same with earthworms, mycorrhizal fungi, and the bacteria needed to feed your plants, create a soil that will support them and they will be there without the need to buy them.
On the other hand, if your soil is not good and healthy then that soil will not support any of these things no matter the source and adding them is simply a waste or your money, time, and energy.

Thanks for your replies. I did figure out that beneficial means good ; ) but I guess I'm asking why the necessity for adding endophytes, when I've had good luck with grass without endophytes in the past. I'm also a little concerned since I do have to wear a face mask when I mow (health problems), and would prefer not to have a beneficial fungi colony in my lungs. (Even if it is 'beneficial'.) lol

kimmsr, I think pretty good as far as the soil goes, since I've pretty much gardened organically since I started about 10 years ago. Thanks.

Got it. No they are not necessary.

I am allergic to one of the more plentiful and beneficial fungi in compost. Fortunately it decomposes to something I'm not allergic to when the compost is finished composting. If I open up my pile prematurely and see it, I need to not exhale and beat feet outta there toward upwind. Then I can breathe safely.

You will find a whole lot of literature out there on Endophytes in Fescue....

Basically -- it falls into 2 camps which are diametrically opposed..
Pasture/grazing
and
Turfgrass

Pasture/grazing/livestock folks hate Endophyte infected grasses -- as they "Poison" the livestock.. The chemicals produced by the Endophytes makes livestock much less heat tolerant... Calves and ewes don't put on as much weight, etc...

Turfgrass folks *Love* endophyte infected grasses.. because they poison things that eat our grasses -- like sod web worms and japanese beetles... Endophyte infected turf grasses have also been shown to be more cold weather and hot weather and drought tolerant than non-infected turf grasses...

So.. If you have things that graze -- seek out Endophyte Free seed... If you want a tougher yard.. Seek out "Medium" or "High Endophyte" seed...

Thanks

John