Paranthrene robiniae (Hy. Edwards) (Lepidoptera: Sesiidae)
As a result of Washington State University integrated pest management (IPM) research (Brown et al. 2006; Kittelson 2006), all commercially grown poplars in the Pacific Northwest for Forest Stewardship Council (FSC) certified products are now protected by a pheromone-based male confusion strategy against western poplar clearwing moths. Professional IPM practitioners can use this publication as a guide toward control of this moth in the Pacific Northwest.
The larvae of clearwing moths (Figures 1 and 2) that attack poplars can be found throughout the US. Paranthrene robiniae occurs west of the Rocky Mountains, P. dollii (Neumoegen) is found throughout the southeastern states (Ostry et al. 1988), and P. tabaniformis (Rottemburg), sometimes called the European poplar clearwing moth, can overlap with both P. robiniae and P. dollii in the central portion of the US. Using commercially available sex pheromones which are species-specific for clearwing moths, we captured another clearwing moth, Sesia tibialis (Harris), also called the cottonwood crown borer, or American hornet moth in eastern Washington (Kittelson 2006). Although not a clearwing species, LaGasa et al. (2001) reported capturing a European species, the poplar shoot moth Gypsonoma aceriana (Duponchel), damaging poplar in western Washington. Another twig borer, G. haimbachiana (Kearfott) has been found in the eastern US attacking P. deltoides (Morris 1967). Both these Gypsonoma species are members of the Tortricidae family of Lepidoptera.
Poplar-and-willow borer larvae, Cryptorhynchus lapathi (L.) (Coleoptera: Curculionidae), also burrow into poplar branches and boles (Hannon et al. 2008).
Larvae of P. robiniae attack poplar, willow, aspen, and birch.
Western poplar clearwing moths are found throughout the states west of the Rocky Mountains, and British Columbia (Lee 2014). Pearson et al. (2010) have reported P. robiniae as far east as western Colorado.
Five larval instars develop within galleries in the bole and stems (Figure 1) of poplars. Multiple pupal cases (Figure 2) are evidence of a large population.
Third through fifth larval instars overwinter (Figure 3) within boles and stems culminating in adults (Figure 4) that emerge from April through July the following year. In April, adults mate and gravid females deposit eggs individually. Pupae found in first year whips suggest a small proportion of each year’s population can be completed within one season.