152 Plant Protection Quarterly Vol.13(4) 1998 • Is blackberry still a problem on pasture All these and other questions arose dur- L. agg. in south-eastern Victoria. Plant land because the message from re- ing the planning of the workshop. An- Protection Quarterly 13, 182-5. search is not reaching landholders? swers to such questions need not neces- McGregor, G. (1998). Relationships be- • What is the optimum combination of sarily follow, but I hope the definition of tween weedy and commercially grown existing control methods for use in dif- future research directions and the exten- Rubus species. Plant Protection Quarterly ferent situations? sion of those existing and new research 13, 157-9. • How can these existing methods be results will flow from the following pro- Milne, B.R. and Dellow, J.J. (1998). Herbi- adapted to areas of natural vegetation, ceedings. cide responses of blackberry (Rubus which often abut waterways or are in- fruticosus agg.) in the Central Table- accessible for conventional methods of References lands of New South Wales. Plant Protec- herbicide application to be used? Amor, R.L. and Miles, B.A. (1974). Tax- tion Quarterly 13, 180-1. • What novel methods of control may be onomy and distribution of Rubus Mueller, F. (1895). ‘Select extra-tropical developed for such ecological situa- fruticosus L. agg. (Rosaceae) naturalized plants, readily eligible for industrial tions, such as mycoherbicides? in Victoria. Muelleria 3, 37-62. culture or naturalization’, 9th edition, • Do we need to look anew in drier areas Amor, R.L., Richardson, R.G., Pritchard, p. 475. (Victorian Government Printer, of Europe for strains of rust better G.H. and Bruzzese, E. (1998). Rubus Melbourne). adapted to drier southern Australian fruticosus L. agg. In ‘The Biology of Parsons, W.T. and Cuthbertson, E.H. climates? Australian Weeds’, Volume 2, eds. F.D. (1992). ‘Noxious weeds of Australia’, • What native plant and animal species Panetta, R.H. Groves and R.C.H. Shep- 692 pp. (Inkata Press, Melbourne and are at risk from encroaching blackberry herd, pp. 225-46. (R.G. and F.J. Sydney). thickets? Richardson, Melbourne). Vere, D.T. and Holst, P.J. (1979a). Using • Which native plant species will be Evans, K.J., Symon, D.E. and Roush, R.T. goats to control blackberries and briars. strongly competitive with weakened (1998). Taxonomy and genotypes of the Agricultural Gazette of New South Wales blackberry plants as a result of imple- Rubus fruticosus L. aggregate in Aus- 90, 11-13. menting control? tralia. Plant Protection Quarterly 13, Vere, D.T. and Holst, P.J. (1979b). The eco- • How much will all this extra research 152-6. nomics of using goats to control Rubus cost? Mahr, F.A. and Bruzzese, E. (1998). The fruticosus. Proceedings of the 7th Asian- • Who will pay for this additional re- effect of Phragmidium violaceum (Schultz) Pacific Weed Science Society Confer- search? Winter (Uredinales) on Rubus fruticosus ence, pp. 207-9. Taxonomy and genotypes of the Rubus fruticosus L. for improved biological control of black- berries. aggregate in Australia Introduction K.J. EvansA, D.E. SymonB and R.T. RoushA Blackberry (Rubus fruticosus L. agg.) is an A Department of Crop Protection and CRC for Weed Management Systems, important weed of natural and agricul- tural ecosystems in Australia and is University of Adelaide, Waite Campus, PMB 1, Glen Osmond, South Australia widely distributed in the high-rainfall re- 5064, Australia. gions of each State. Weed managers use B The Botanic Gardens of Adelaide and State Herbarium, North Terrace, the common name ‘blackberry’ to encom- Adelaide, South Australia 5000, Australia. pass all the Rubus taxa that comprise this aggregate. An ability to recognize the different Rubus taxa is a skill weed man- Summary agers could use to monitor the coloniza- Blackberry (Rubus fruticosus L. aggre- precise information regarding the tion and spread of individual taxa. New gate) is an important weed of agricultural amount and distribution of genetic vari- approaches for blackberry management, and natural ecosystems in Australia. ation within Rubus. We present the use such as biological control, require a know- Weed managers require accurate taxo- of DNA fingerprinting as a tool for (i) ledge of blackberry taxonomy because nomic keys for Rubus so that they can determining the genotype of an indi- biocontrol agents may provide more effec- identify which taxa are contributing to vidual plant, (ii) estimating the genetic tive control of some taxa when compared the weed problem. Blackberry comprises variation within and among Rubus taxa, with the level of control of other taxa. a few diploid sexual species (e.g. R. and (iii) clarifying some taxonomic prob- Taxonomic keys for Rubus are available in ulmifolius) and a large number of poly- lems in the genus Rubus. Twenty differ- each State, but there are inconsistencies ploid agamospecies (e.g. taxa in Aus- ent genotypes were identified among 13 among the States in the names provided. tralia named R. polyanthemus, R. different Rubus taxa. No genetic varia- The status of Rubus taxonomy in Aus- laciniatus and the widespread R. affin. tion was observed among 50 plants of R. tralia is explained partly by the general armeniacas (= R. discolor sensu auct. affin. armeniacas sampled from 29 loca- taxonomic problems encountered in the aust. non Weihe & Nees)). We review the tions throughout Australia, suggesting genus Rubus. In Europe, only a few dip- status of Rubus taxonomy in Australia that this common blackberry is probably loid blackberries, including R. ulmifolius, and present some new information re- a single clone. In contrast, seven differ- can be treated as true sexual species. The garding existing taxa based on collec- ent genotypes were observed among 26 remaining taxa in R. fruticosus L. agg. are a tions made in South Australia and exam- plants of R. ulmifolius sens. lat. sampled complex of polypoid and apomictic ined by Rubus specialists in Europe. The from six locations in Victoria. Two of biotypes (Asker and Jerling 1992, Nybom utility of Rubus taxonomy for research these genotypes were sampled from a 1995, Weber 1996). Apomixis, however, is workers and weed managers is also ex- single thicket of R. ulmifolius sens. lat. facultative, which means that a small pro- amined. Whereas the biological species We illustrate the utility of genotyping portion of seed may be produced sexually concept may be useful for weed manag- Rubus plants in studies to identify viru- as a result of hybridization between ers, research workers often require more lent strains of the European rust fungus apomicts or between apomicts and sexual Plant Protection Quarterly Vol.13(4) 1998 153 species (Nybom 1988, 1995). Spontaneous but is based on a study of Victorian taxa F15, was released in all Australian States as hybrids may have a limited local distribu- conducted in the 1960s (Amor and Miles a biological control agent in the summers tion or become a stabilized clone with a 1974). In all States, there are likely to be of 1991 and 1992. Although R. laciniatus is wide distribution. These biotypes, in ad- some Rubus taxa that cannot be given a classified as a resistant biotype when in- dition to forming large or small popula- species name because their morphology oculated with strain F15 (Bruzzese and tions, differ from one another in large or is different from that of taxa described Hasan 1986a) , it shows symptoms of rust small degrees (Weber 1996). The most re- in Europe. The distribution of the well- disease in the field (E. Bruzzese personal cent account of Rubus in Britain lists 307 defined taxa can be implied from her- communication). This taxon is probably species with even more in continental Eu- barium records, but the last detailed study being infected by the strain, or strains, of rope where taxonomic studies are incom- of taxon distribution (Amor 1971) again rust that were introduced illegally to plete (Edees and Newton 1988). Given that relates only to Victoria in the 1960s. A na- southern Victoria in 1984. In regions the taxonomic treatment of blackberry tional review of Rubus taxonomy and the where the rust disease is severe, continues to evolve, Weber (1996) pro- distribution of taxa is warranted so that landholders are advised to identify black- vides criteria for allocating apomictic inconsistencies among the States are mini- berry thickets showing no symptoms of biotypes to a ‘taxonomic species’, based mized and so that weed managers can de- rust disease and to note which species are mainly on the range of distribution of the fine more accurately which taxa are con- present in an attempt to identify taxa that biotype. tributing to the weed problem. may be resistant to the strain, or strains, In Australia, the different blackberry Accurate taxonomic keys would en- of rust fungus present in that location taxa are grouped as the R. fruticosus L. ag- hance research efforts to improve the bio- (Bruzzese and Lane 1996). If these thickets gregate. Because of the subtle differences logical control of blackberry using the Eu- are allowed to expand, then the black- between these taxa and the inadequate ropean rust fungus. Blackberry leaf rust is berry infestation is maintained by replac- amount of reference material that has been a disease of blackberry caused by Phrag- ing one taxon with another. This phenom- authenticated, the names of the biotypes midium violaceum (Bruzzese and Lane enon occurred in the biological control introduced in this country are debatable. 1996). The susceptibility of different Rubus program for skeleton weed (Chondrilla The Rubus section of the Flora of Victoria taxa to individual strains of the European juncea) where the narrow-leaf form was (Walsh and Entwisle 1996) includes many rust fungus varies (Bruzzese and Hasan controlled successfully by a strain of the of the names applied in Australia to date 1986a,b,c).