Glandular trichomes affect mobility and predatory behavior of two aphid predators on medicinal cannabis

•On C. sativa, non-glandular trichomes predominate on leaves, and glandular trichomes on flowers.•Phorodon cannabis and Aphis gossypii are major aphid pests of C. sativa.•Larvae of both Aphidoletes aphidimyza and Chrysopa carnea foraged effectively for aphids on leaves.•A. aphidimyza mobility and foraging was impeded on flowers, but C. carnea remained effective.•Augmentation of A. aphidimyza on C. sativa should be restricted to vegetative growth stages.