The U.S. cut flower market was valued at approximately 9.2 billion USD in 2021 and is projected to grow to nearly 12.8 billion USD by 2028, with a steady compound annual growth rate of 4.8%. While irises make up a smaller share of this market, their visual appeal and versatility give them lasting economic and cultural value. Some varieties even pull double duty—producing rhizomes used in perfumes and traditional medicine. For South Carolina, ornamental horticulture is more than just aesthetics—it’s a key part of the state’s thriving green industry. Irises—particularly a wide range of native and cultivated varieties/cultivars—play a notable role in this sector, contributing to landscape diversity, wetland restoration, and the ornamental plant trade.
However, iris growers across the region may be facing an unseen threat. We recently discovered a dipteran leafminer, tentatively identified as Cerodontha sp., causing significant damage in iris production areas. A quick survey of major plant outlets in Florence, SC revealed that most Louisiana iris plants were infested, with damage easily mistaken for abiotic stress like overwatering or nutrient issues (Figure 1).
What to Look For:
- Yellowing and wilting of iris leaf blades (Figure 2)
- Short, whitish serpentine tunnels near the base of leaves (Figure 2)
- Iris plants failing to bloom
Detecting and monitoring the leafminer life cycle in your area is the first step in effective management. Many growers have had difficulty managing leafminers, and a key early task is confirming whether the symptoms observed are actually caused by leafminers. This involves locating mines and inspecting them for visible life stages such as larvae, pupae, or empty trails. Misdiagnosing the symptoms or mistiming treatments can significantly reduce control efficacy, especially when insecticides are applied during periods when the pest is in the egg, pupal, or inactive larval stage—times when it’s least vulnerable and least exposed to control measures.
If you find damage on your irises:
Please contact Dr. Zee Ahmed at mahmed2@clemson.edu or (352) 283-0173 for support with identification and management.
