Mature Indian Wax Scale on Twig.
Photo: Matt Bertone, NC State University
Updated: August 16, 2022
Indian Wax Scale (Ceroplastes ceriferus) is a non-native type of soft scale insect and can be difficult to manage. Their waxy body covering shields them from predators and certain pesticides. Learn more about scale insect groups and biology on Introduction to Scale Insects.
This is a common pest of hollies and a range of shrubs and can cause leaf drop and dieback when populations are high.
The crawler emergence period depends on temperature and can vary slightly from year to year. The approximate time to monitor for them is June.
They overwinter on the bark as adults.
Refer to our general scale management recommendations for both chemical-based and pesticide-free options. When pesticides are warranted, a combination of dormant oil applications and the use of systemic or growth-regulating insecticides is the most effective approach. For large populations, scale suppression may require more than one year of intervention, and professional pesticide applicators will be needed to apply certain treatments.
The brief crawler emergence period for this species means that monitoring and treatment may need to occur in a relatively limited timeframe.
Just before the expected emergence period, start monitoring for crawlers. Since weather trends can shift date ranges, a more reliable prediction of timing can be made using Growing Degree Days and Plant Phenological Indicators. Here is a refined estimate of egg hatch and the beginning of crawler emergence:
1145 degree days
During the flowering of Bottlebrush Buckeye (Aesculus parviflora)
Before the flowering of Mimosa (Albizia julibrissin; invasive)
Adapted from, Managing Insects and Mites on Woody Plants, authors: Ph.D. John A. Davidson, Ph.D.and Michael J. Raupp, Ph.D. The Pest Predictive Calendar, and Scale Crawler Emergence Period chart compiled by Stanton Gill, Suzanne Klick, and Sarah Kenney.
Complied by Miri Talabac, Horticulturist & Coordinator, HGIC 2022