Question
I have a lawn that each year has an area that has the grass dying in light yellow patches and streaks.  Always in the same places.  The rest of the lawn is healthy and grows nicely.  I have tried insecticides, and it seems to little good.  The grass comes back as the weather cools.  Any idea what the problem might be?

Answer
Dear Bannie:

Without knowing what kind of turf and where you are, I can only guess from your description.  You have excluded insects if the pesticides do little good.

The problem may be fungus or debris/contaminants left underground.  If a fungus, there should be other signs, such as mushrooms or a mycelial growth (white matter) just underneath the turf.  With contaminants, a soil and tissue test should reveal the culprit.  For debris, poking a rod into the soil may show a hard piece of wood or old root draining nitrogen or feeding fungus.

Fungal activity has a temperature range.  Summer where you are may provide that ideal temerature.  If a fungus, a fungicide will act on it if it is on the grass plants.

Just some ideas common to lawns.

A tissue analysis may be in order.  Take some whole grass plants from the area to a local ag agent for testing at a state facility.  It may be required to furnish some healthy samples also for comparison.  Call to find out what to do.

Best wishes.