Research entomologist Grant Kirker reports, “Host plant resistance is an environmentally friendly, low-tech, low-cost method of control that reduces the need for pesticides to manage azalea lace bugs.” The study, conducted at the USDA-ARS Thad Cochran Horticultural Research Laboratory in Poplarville, Miss., studied 19 varieties of Encore Azalea and 14 standard cultivars for host plant resistance to lace bugs.
Encore Azalea cultivars found to be resistant included: Autumn Amethyst, Autumn Twist, Autumn Royalty, Autumn Sangria, Autumn Cheer, and Autumn Rouge. Cultivars showing moderate resistance were Autumn Embers, Autumn Bravo, Autumn Starlite, Autumn Ruby, and Autumn Princess.
Azalea lace bugs are a major pest in both production nurseries and home landscapes. Adult bugs use their piercing mouthparts to suck the juices from the undersides of the leaves, leaving a yellowish stippling on the upper and lower leaf surface. Severe infestations can lead to reduced plant vigor and loss of leaves.
Researchers are hopeful that this new knowledge will lead eventually to the breeding of pest-free cultivars.