Bob, have you checked for slugs and snails? They love wet climates.

They crawl onto the stalk of the plant and start eating, they may crawl
up further and eat leaves or the stalks of leaves, but mostly they seem
to start right at the bottom of the main stalk damaging it so much that
the whole plant wilts and falls over.

If slugs and snail are the problem, you can buy traps or you can bury
opened cans of beer so that they fall in. The easiest method to control
them is to pick them off the plants when they are active at night.

Small snakes like to eat them.

Ken

Bob wrote:
I try to grow basil in seattle, and this year am losing a number of plants,
2-4 inches tall, that are just wilting, drying up and dying. I believe they
are getting plenty of water. Maybe too much? Does anyone have any idea what
the cause or solution could be to stop this problem? Is it something that
will spread to the other plants?

Bob