2015 journal article

Assessment of environmental conditions and preferences for rearing the balsam woolly adelgid (Hemiptera: Adelgidae) on host material

Journal of Entomological Science, 50(3), 157–167.

By: E. Mester n, J. Frampton n & F. Hain n

co-author countries: United States of America 🇺🇸
Source: NC State University Libraries
Added: August 6, 2018

The optimal environmental conditions for rearing the balsam woolly adelgid, Adelges piceae (Ratzeburg) (Hemiptera: Adelgidae), on its natural host, Fraser fir, Abies fraseri (Pursh) Poir, was determined by varying temperature, photoperiod, and humidity as well as by evaluating texture and geotaxic preferences. Five locations with a set temperature and relative humidity (RH) were chosen to test for optimal environmental conditions: three environmental chambers maintained at 17, 20, and 25°C with 75% RH; an insectary maintained at 21.1°C and 72% RH; and a greenhouse with varying temperature and RH levels. Overall, 20°C appeared to be the optimal temperature for development, and 25°C was the least favorable of the temperatures tested. Comparing Fraser fir cuttings to seedlings, seedlings (15.51/cm) were five times more infested than cuttings (3.02/cm), and the percentage of adult survival was higher on seedlings (67%) than on cuttings (17%). The highest percentage of adelgids reaching full development occurred in adelgids that inserted around the buds. Although the numbers were very low, full development was reached on logs in all five environments. Texture of the bark plays a role in A. piceae preference, with twice the number of crawlers inserting into medium-textured bark compared to rough-textured bark. Adelges piceae showed positive geotaxis preference, with the most favorable insertion sites on the bottom sides of vertical bark discs. Future rearing of adelgids in the laboratory should be on logs or seedlings in an area of sufficient size to permit adequate airflow at 20°C and 75% RH.