I want to get some beneficial nematodes, primarily for control of fleas
and Japanese beetles. In looking over the various websites that sell
them, I see wildly different recommendations for numbers and coverage,
anywhere from 5million/300sqft (gardensalive.com) to 1million/2000sqft
(thebeneficialinsectco.com). If I use gardensalive's recommendation,
it would cost me about $600 to treat my lawn. If I use
thebeneficialinsectco's numbers and buy from them, it would cost me
about $90.

Is there any reason for this massive difference? Is it based in
reality, or just marketing hype?