Response of the galling insect Aciurina trixa Curran (Diptera: Tephritidae) to host plant quality

Female host plant selection, oviposition behavior, and offspring performance of the gall-forming tephritid Aciurina trixa Curran (Diptera: Tephritidae) on NPK-fertilized and control plants of Chrysothamnus nauseosus hololeucus Pall. (Britton) (Asteraceae) were studied in northern Arizona, USA. There was no statistically significant difference in the proportion of females that selected control versus fertilized plants, and between the time to accept control versus treatment plants. Females laid fewer eggs and spent a longer time ovipositing on control plants than on treatment plants. Larval performance (measured as time of first gall appearance on plant, gall diameter, and larval weight) was not statistically different between fertilized and control plants (P > 0.05).

Shearing and Growth of Five Intermountain Native Shrub Species

We investigated growth of native Intermountain West shrub species sheared yearly. Five shrub species with potential for use in naturalized landscapes and roadside reclamation, silver sage (Artemesia cana), rabbitbrush (Chrysothamnus nauseosus), red-stem dogwood (Cornus sericea), chokecherry (Prunus virginiana), and curlleaf mountain mahogany (Cercocarpus ledifolius), were planted as seedlings in summer 1989. From 1991–1993, half of the plants were sheared to within 0.15 m (0.5 ft) of the ground every spring prior to or at budbreak. Crown height and crown cross-sectional area were measured every year prior to pruning. Significant shearing effects were detected in some shrubs the first year after shearing, with crown area affected more than height. Height of three species with a multistemmed habit, C. nauseosus, A. cana, and C. sericea, was unaffected by shearing both years. Crown area of all species except C. sericea was reduced by shearing. All species were able to regrow to at least 50% of the crown area and 70% of the height of the unsheared plants, suggesting they would be able to tolerate shearing as a management tool with little to no loss of vigor.