Monitoring the Scale, Managing the Moth

• Jordan Lynch, Agriculture and Natural Resources, University of Delaware

• Brian Kunkel, Extension Specialist – Ornamentals Integrated Pest Management, University of Delaware

Effective integrated pest management (IPM) relies on understanding pest phenology and host-pest interactions. This summer, I monitored the seasonal activity of crape myrtle bark scale (CMBS) crawlers, documented box tree moth (BTM) caterpillars, evaluated red-headed flea beetle (RHFB) feeding on Itea, and teamed up with the Delaware Department of Agriculture. Twenty-seven crape myrtles were monitored weekly at the Carvel Research and Education Center to track crawler emergence and compare populations with previous years. Crawler populations were documented using double-sided tape traps and then identified microscopically by their distinct purplish-pink color. The first generation’s population peaks mid-to-late June, with the second generation peaking in early August, which coincides with previously collected data. I scouted landscapes in Dover, Delaware for active BTM infestations and helped maintain a BTM colony in cages kept in the laboratory to observe their developmental stages. Ninety ‘Henry Garnet’ Itea plants located at Johnson Farms were randomly assigned to one of three fertilizer treatments (30 plants per treatment): no fertilizer, half the recommended fertilizer rate, or the full recommended fertilizer rate. Foliation and color ratings, plant measurements, and RHFB counts were conducted weekly. Analysis at thirty-two days after fertilization revealed that the fertilizer rate had a statistically significant effect on both foliar and color ratings. Plants receiving half and full fertilizer rates exhibited significantly greater RHFB foliar damage than unfertilized plants, while the full-rate treatment produced the highest color ratings. Findings were shared through community outreach events and the weekly newsletter, Ornamental Hotline, to guide home gardeners, nursery professionals, landscapers, and Extension educators in sustainable ornamental pest management. Continued monitoring and research will help refine pest phenology models and fertilizer recommendations, ultimately strengthening sustainable pest management strategies for ornamental plants and the professionals and gardeners who maintain them.