Latest report confirmed crapemyrtle bark scale infestation in Pennsylvania – the most northern occurrence in the United States

Researchers from Penn State University and USDA, Dr. Michael J. Skvarla and Dr. Scott A. Schneider, recently published a report confirming a new infestation of crapemyrtle bark scale (CMBS) in Pennsylvania. This report furthered the CMBS distribution to the northeastern part of the United States, bringing the total number of states with CMBS infestations to 18, which includes Alabama, Arkansas, Delaware, Florida, Georgia, Kansas, Louisiana, Maryland, Mississippi, New Mexico, North Carolina, Oklahoma, South Carolina, Tennessee, Texas, Virginia, Washington (EDDMapS, 2022) and Pennsylvania.
According to the report, CMBS was found on a mature crapemyrtle tree in Pennsylvania, Chester County, Pennsbury Township (USDA Plant Hardiness Zone 6b), one of the warmest regions of Pennsylvania. The insect samples were collected and identified as CMBS in the summer of 2021. However, the authors believe that the CMBS infestation might have persisted for several years, considering the severity of the infestation in question (Figure 1).

This report supports previous models constructed by Wang et al. (2019), which predicted that the crapemyrtle bark scale could survive in more northern areas than previously found in the United States, including most of Pennsylvania. In China, CMBS infestations were found in Beijing (USDA Cold Hardiness Zone 6) (Figure 2), which has a similar latitude (around 39°53’29.03” N) compared to the location of the new CMBS infestation reported in Pennsylvania. The authors also stated that since crapemyrtle is pruned back to the roots every year in colder areas of the state, scale infestations will likely be minimal due to this pruning practice.

Reference

1. EDDMapS. 2022. Early Detection & Distribution Mapping System. The University of Georgia – Center for Invasive Species and Ecosystem Health. Available online at http://www.eddmaps.org/; last accessed May 8, 2022.
2. Skvarla, M.J. and Schneider, S.A., 2022. First Record of Crapemyrtle Bark Scale (Hemiptera: Eriococcidae: Acanthococcus lagerstroemiae) from Pennsylvania. Proceedings of the Entomological Society of Washington, 123(4), pp.862-868.
3. Wang, Z., Y. Chen, and R. Diaz. 2019. Thermal tolerance and prediction of northern distribution of the crapemyrtle bark scale (Hemiptera: Eriococcidae). Environmental Entomology 48(3): 641–648.
4. Gu, M., Merchant, M., Robbins, J. and Hopkins, J., 2014. Crape myrtle bark scale: A new exotic pest. EHT-049, 3(4).