Forest Pest Insects in North America: a Photographic Guide

Red oak clearwing borer

Paranthrene simulans (Grote) (Lepidoptera: Sesiidae)

Orientation to pest

Red oak clearwing borer, Paranthrene simulans (Grote), is a native North American clearwing moth that affects American chestnut (Castanea dentata [Marsh.] Borkh.) and some oaks. It is widespread in both eastern Canada and the eastern United States. Adult moths emerge from April to June in the southern parts of the species' range and June and July in the northern portion. Females lay eggs in bark crevices on the lower trunk. Larvae burrow in the inner bark and create ovoid chambers. As larvae grow, they extend their galleries. Larvae overwinter for two winters in their galleries. In spring, after the second winter, larvae bore to the bark surface, cap the gallery exits with a thin membrane, and then pupate. The whole life cycle requires two years. Open-grown trees are attacked most often. Bark swelling, pellet-like frass in bark cracks, and empty pupal cases on the trunk are visible signs of attack by this borer. Tunneling causes losses to nursery tree production and promotes decay in the lower butt, below the cut made for harvest. Pheromone traps are available to monitor moth flight to time pesticide applications.

Hosts commonly attacked

This borer attacks American chestnut (C. dentata) and species in both the red and white oak groups. Moth preference among hosts varies by region. In the southern United States older Nuttall (Quercus texana Buckl.), cherrybark (Quercus pagoda Rafinesque), Shumard (Quercus shumardii Buckland), and eastern black (Quercus velutina Lamb.) oaks are the principal hosts. In the northeastern United States, injury is greatest in nursery stock and sapling red or white oak group trees.


This borer occurs in the eastern parts of Canada and the United States, north to Minnesota and south and west to Texas.

Images of red oak clearwing borer

Adult red oak clearwing borer Daniel Herms, The Ohio State University, 768x512 / 1536x1024
Adult red oak clearwing borer James Solomon, USDA Forest Service, 768x512 / 1536x1024
Emergence holes of red oak clearwing borer on lower trunk of Nuttall oak James Solomon, USDA Forest Service, 768x512 / 1536x1024
Figure 1. Adult red oak clearwing borers, Paranthrene simulans Figure 2. Larva of red oak clearwing borer in it gallery Figure 3. Emergence holes of red oak clearwing borer on lower trunk of Nuttall oak

Important biological control agents related to this pest species

No information is available of the natural enemies of this species.

Web links for information on red oak clearwing borer