Galls Induced by Diplolepis spinosa Influence Distribution of Mineral Nutrients in the Shrub Rose
| Autor: | G. Bagatto, J.D. Shorthouse, T.J. Zmijowskyj |
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| Rok vydání: | 1991 |
| Předmět: | |
| Zdroj: | HortScience. 26:1283-1284 |
| ISSN: | 2327-9834 0018-5345 |
| DOI: | 10.21273/hortsci.26.10.1283 |
| Popis: | Mineral nutrient levels in tissues of the domestic shrub rose (Rosa rugosa Thunb.) were examined following gall induction by the cynipid wasp Diplolepis spinosa (Ashmead). Higher levels of Cu, Zn, Fe, Mn, and Ni were found in the galls, leaves protuding from the galls, and stems to which galls are attached than were found in normal stems and leaves, indicating that cynipid galls alter the nutritional status of their hosts. Cynipid galls must be removed or controlled because the stress they cause will increase the vulnerability of roses to attack by other pestiferous insects. Two species of gall-inducing cynipid wasps (Diplolepis spinosa and Diplolepis radicum (Osten Sacken)), normally found only on the wild rose (Rosa blanda Ait.), are now at- tacking the domestic shrub rose in Canada and the northern United States (Shorthouse, 1988). Although galls of both species alter the aesthetic appearance of shrub roses, there have been no attempts to determine whether or not these insects cause structural or phys- iological damage. Most gall-inducing insects are thought not to cause host damage; how- ever, there are studies showing that galls are physiological sinks for assimilates and macronutrients (Abrahamson and Weis, 1987). Here we report on how one of these insects, the stem-galler Diplolepis spinosa, alters the nutritional status of attacked stems. Diplolepis spinosa is a small, rufous-or- ange cynipid wasp, the larvae of which in- duce a large, spiny, multi-chambered stem gall (Fig. 1). Like all gall insects, D. spinosa receives food and shelter from the host plant as the larvae stimulate and then control wound or defensive reactions of attacked organs. The ical galls in the maturation phase. Each of the stems was 30 cm long and was re- moved from an urban roadside flower bed in Sudbury, Ont. The normal stems were sep- arated into leaves and the top 5 cm of the stem. The galled stems were separated into a 5-cm sample of stem below the gall, leaf tissues associated with the gall, and tissues of the gall itself. Stem and leaf samples for each category of tissue were pooled, oven- dried, homogenized in a plant mill, and di- gested in boiling aqua regia, and elemental analysis was performed by flame atomic ab- sorption spectrophotometry. Gall tissues were not pooled, and each was analyzed sepa- rately. Details of the analytical technique are described by Bagatto and Shorthouse (1991). Values for Ca, Mg, and Mn in the leaves and stems of the control samples (Table 1) are considerably lower than those reported in the literature (Carlson and Bergman, 1966; Diaz et al., 1985; Johansson, 1978); how- ever, the study plants appeared healthy and were producing numerous blossoms. Values for the remaining nutrients in the nongalled stems fall within the range considered ade |
| Databáze: | OpenAIRE |
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