Daylily Leafminer Causing White Streaks on Daylilies
The Daylily leafminer is a recent pest from Asia. It was first detected in 2006 but has now spread through much of the Southeast including North Carolina. I spotted the first mines of the year this week.
This small black fly lays its eggs in daylilies leaving a linear brown scar. The larvae produce relatively straight white mines that are parallel to the leaf veins. Pruning infested leaves may help prevent the larvae from maturing and infesting new leaves but this fly seems so ubiquitous that it is probably a futile effort.
We are conducting efficacy tests on this pest right now so I should have recommendations for next year. But for now materials already registered for other leafminers such as abamectin, spinosad, and others in the new Southeastern Pest Control Guide for Nursery and Landscape Plants could help. More information about this pest is on our research page.