I've been reading about plants purchased from Home Depot, Walmart and Menards killing bees. The seeds are treated with chemicals that kill the bees that visit the plant.

Where have you been reading this?

I can't think of any "chemical" that is so danged strong that a bit of it on a SEED would continue to be lethal all the way into a blooming plant ... and into the pollen and nectar.

ARE NEONICOTINOIDS KILLING BEES?
A Review of Research into the Effects of Neonicotinoid Insecticides
The Xerces Society for Invertebrate Conservation:

Are Neonicotinoids Killing Bees?
Neonicotinoid pesticides were first registered for use in
the mid 1990s. Since then, these chemicals have become
widely adopted for use on farm crops, ornamental land
scape plants, and trees. Of the six neonicotinoids com-
monly used on plants, the most widely used is imida-
cloprid. Neonicotinoids are systemic chemicals; they are
absorbed by the plant and are transferred through the
vascular system, making the plant itself toxic to insects.

Legislators, regulators, and municipal leaders across
the country should consider banning the use of
neonicotinoid insecticides for cosmetic purposes on
ornamental and landscape plants (as the ban now
in force in Ontario, Canada). Approved application
rates for ornamental and landscape plants, as well as
turf, are often much higher than for farm crops.
All neonicotinoid products used by commercial
and agricultural applicators should include a clearly
stated and consistent (standardized) warning on the
label about the hazard to bees and other pollina
tors, including the unique exposure issues posed by
contaminated pollen and nectar. This is particularly
important for products marketed for garden and
ornamental use.

This is information that SHOULD be labelled, but I do not think it has yet. I have a concern about where my garden plants are grown and what chemicals are used. We are killing our bees.