Question
Last year my asian pear had abundant pears, but this year it has very few pears. I have noticed that the leaves have something that looks like a white thread  that completely cover the leaves top and bottom.

Answer
Go to Lowes and get some all purpose insecticide.  Spray liberally.

This sounds like white powdery mildew.  Not good.

If you want to go organic.  Get Atomic Grow.

www.atomicgrow.net
crowleynursery.net  nursery tab

Atomic Grow is a new product that will clean up your problems and make your tree super healthy and lush at the same time.

James