Adults and larvae of the cottonwood leaf beetle, Chrysomela scripra Fab., defoliated tissue cultured Aigeiros (Populus x euramericana (Dode) Guinier) subclones and destroyed apical tips. Fecundity was 510±l53 eggs (X±S). Four generations occurred between May and September in southern Wisconsin. Maximal insect numbers and damage occurred in the third generation. The minimal developmental threshold was 10.8°C with a mean 257±226 day-degree (°C) required per generation. Important biological control agents included Coleomegilla maculara, which consumed up to 25% of the eggs, and Shizonatus latus, a pteromalid parasite, which destroyed up to 26% of the pupae.© 1979, Entomological Society of Canada. All rights reserved.
