Hi all.
I want to spruce up my knowledge of greenhouse and nursery crop pests and diseases and what they look like and the damages they cause. Anyone know of good textbooks that breaks all these topics down? I work at a garden center so this would help a lot if I can find something good and isn't $1oo per book ;) Thanks in advance.

This one is great: Garden Insects of North America, by Cranshaw, Whitney
$27
Some of the pictures will gross out customers.