AngryFish said:

What do you think happened to our lawn? The yellow streaks that you
see in the pictures came on in a matter of a couple of days.

1. Fertilizer burn. Fertilizer was applied last week.
- or -
2. Not enough water. Temperature was in the mid to upper 90s all
last week. Grass was only watered every other day for 10-15 minutes.

Fertilizer burn, probably aided and abetted by the hot, dry conditions.

Fertilizing in the heat of summer without adequate irrigation is asking
for trouble.
--
Pat K.

Any technology distinguishable from magic is insufficiently advanced.
(attributed to Don Marti)