AUBURN, Ala.--Scientists say nurseries in both north and south Alabama are battling the European pepper moth, Duponchelia fovealis. The moth (EPM),a relatively new pest in Alabama, comes originally from both salt and fresh water marshlands of southern Europe. First reported in the United States in 2004, the pest's range began expanding in Europe in the early 1980's.
Alabama Extension horticulture specialist Dr. Jeremy Pickens said that damage from larvae may be responsible for crop loss between 10 to 20 percent.
Adult moths are mostly nocturnal and grayish brown in color with a wingspan of about 0.75 inches (Figure 1). Larvae are small, segmented caterpillars. At hatching, they measure just under 0.1 inch in length with a dark colored head and salmon body. As they mature, they darken and eventually reach 0.7 to 1.25 inches long (Figure 2).
"In northern states, 7 to 8 generations have been observed within a year; however, warmer temperatures can mean shorter lifecycles," Pickens said. Research results from Bethke (2017) show that EPM can complete development from egg to adult in as as little as 20 days when temperatures stay at or above 90°F.
European pepper moth feeds on all parts of a wide variety of host plants. In chrysanthemums, noticeable symptoms may first appear as flagging or a slight wilting of new growth (Figure 3). Eventually, the entire plant will succumb to the damage, wilt and die. Wilting is a result of feeding damage by stem girdling at the plant base. Also, webbing and frass can be observed in the same area (Figure 3).
Be aware damage from EPM on chrysanthemum is easily misdiagnosed as Fusarium. As growers space plants outdoors, heat stress and excessive moisture can dramatically increase the disease pressure for Fusarium. The symptoms of Fusarium may include partial wilting of a plant and brown streaking on the outside of stems or in the vascular system of the plant (Figure 5 and 6). White- or salmon-colored structures may also be present on advanced infections (Figure 7). More information on Fusarium on garden mums can be found at Greenhouse Management and University of Kentucky. In some cases, both EPM and Fusarium have been confirmed infecting the same plant.
Literature in other states have listed that neonicotinoid, pyrethroid, spinosid and BT products as being effective. Little control with these products have been observed in south Alabama when these products were applied with high-pressure airblast sprayers. The dense canopy associated with chrysanthemum may inhibit contact with larvae present at the base of the plant.
In addition, chemical treatments may be more effective if low-pressure nozzles are inserted into the canopy of the plant about 1.5 inches from the soil line where chemicals are more likely to make contact with the pest. Current recommendations include targeted sprays of contact insecticides such as acephate or bifenthrin. Acephate seems to be the most effective chemical for use as a spray or drench. A study in Florida showed that Enfold (emamectin benzoate) can provide residual control; however, spinosad (Conserve) was not very effective (Bethke et al. 2017). Regular broadcast applications of Bacillus thuringiensis (XenTari®/DiPel®) may provide some suppression of young larvae.
Pheromone lures are available for monitoring purposes at BIOBEST USA www.biobestgroup.com.
More information about the European Pepper Moth can be found at the following links:
University of Florida IFAS Featured Creatures
University of Kentucky Entomology
University of Maryland IPM Alert
Bethke, J., A. Hara, L. Osborne, C, McKenzie, and C, Palmer, 2017. Developing sustainable methods for controlling invasive pests pre- and post invasion on ornamental cuttings and plants. IR-4 Research Project Report http://ir4.rutgers.edu/Ornamental/SummaryReports/
ArthropodShippingandDuponchelia_USDA-APHIS_ProjectSummary.pdf last accessed 8/29/17.
If you have questions please contact your Alabama Extension regional commercial horticulture agent.
Find your Alabama Extension Commercial Horticulture Agent
Doug Chapman, Extension Agent
Jeremy Pickens, Extension Specialist, Greenhouse Nurseries
John Olive, Ornamental Horticultural Research Station
David Held, Associate Professor, Department of Entomology
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