B3   >>   BCANZ home   ·   Search database   ·   Browse database

Biocontrol introduction

Target pest: Asterodiaspis quercicola (Hemiptera: Asterolecaniidae), pit scales

Agent introduced: Habrolepis dalmanni (Hymenoptera: Encyrtidae)

Imported: 1923-28

Import source: Massachusetts, USA

Released: 1923-28

Release details: 9 adults were released in Christchurch in 1923 and 159 in 1928. There were releases in Nelson from 1924 -28 (152 in insectary and 464 in the field). Redistributed from 1929 to 1938

Establishment: Established and spread quickly

Impacts on target: Caused an apparent improvement of oak tree health but pit scales are common and still cause damage.


Cameron PJ, Hill RL, Bain J, Thomas WP (1989). A Review of Biological Control of Invertebrate Pests and Weeds in New Zealand 1874-1987. Technical Communication No 10. CAB International Institute of Biological Control. DSIR Entomology Division. 424p.