Dear Allison Justice

Try to use Trichoderma harzianum against root aphids could be useful rather than entomopathogenic nematode. Good luck

You might look at boosting the plants natural symbiots that are already there. I can send you information on a Plant Defender product that does that. If interested. We have found focusing on building the plants natural mutualistic relationships is best. "Who they are already friends with"

You can try Lecanicillium lecanii, an effective mycoinsecticide against root aphids

There are many studies that use a combination of both entomopathogens and that generate higher mortality. As Fungis have a long life cycle, you must apply them first and after 2 days you can apply EPN.