Received from:
Contact: Dr. John L. Foltz
Department of Entomology and Nematology
University of Florida
foltz@ufl.edu
or
Dr. Bud Mayfield
Division of Forestry
Florida Department of Agriculture and Consumer Services
mayfiea@doacs.state.fl.us
Recent reports from south-central Florida indicate that the pinkstriped oakworm (Anisota virginiensis) was unusually abundant and severely defoliated numerous oaks during August and September. In some areas moths are now flying and laying eggs that are likely to produce another horde of caterpillars before winter. People who experienced oakworm defoliation of their trees earlier this year should monitor those trees closely in the coming weeks to assess the possible impact of further defoliation on tree health. Here are some questions to answer and factors to consider in your assessment:
Most healthy oaks can withstand a single severe defoliation with little overall impact on their health and growth. Repeated defoliations, however, can reduce carbohydrate production and reserves and leave a tree susceptible to attacks by secondary insects and pathogens. If your oak was already seriously defoliated this year and has produced a new set of leaves, another heavy defoliation could place considerable stress on the tree. If you detect numerous eggs or recently-hatched caterpillars on the new foliage, you may wish to apply an appropriately-labeled insecticide to this late-fall generation of oakworms while they are still small.
For further information on the identification, biology and management of the pinkstriped oakworm, see the excellent article recently prepared by Okeechobee extension agent Dan Culbert. It is available at http://okeechobee.ifas.ufl.edu/News columns/Pinkstriped Oakworm.htm.
Another website with more information and pictures of adults and the mature caterpillar is located at http://www.npwrc.usgs.gov/resource/distr/lepid/moths/fl/953.htm.