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RUSH SKELETON WEED

Chondrilla juncea L. -- Asteraceae

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Rush skeletonweed is a perennial herbaceous species belonging to the tribe Cichorieae of the Asteraceae family. It was introduced to Australia around 1910, and spread rapidly throughout the wheat belt of southeastern Australia. Chemical and cultural methods alone or in combination did not give satisfactory control. A program aimed at biological control was initiated by the CSIRO in 1966. An experimental station was established at Montpelier, in southern France, so that the ecology of the weed might be studied in its native range and potential natural enemies identified. AT the same time, studies in Australia revealed the presence of three morphologically and genetically distinct forms of C. juncea.

A strain of the rust, Puccinia chondrillina Bubak & Sydow, was introduced from southern Italy to Australia in 1971 and spread rapidly to all infested areas. But this particular strain of rust caused significant reductions in densities of Form A in all areas. Other organisms introduced, but having a lesser impact on skeletonweed, included a gall midge, Cystophora schmidti Rubsaamen (Diptera: Cecidomyiidae), a gall mite, Aceria chondrillae Can. (Acari: Eriophyidae), and a root moth, Bradyrrhoa gilveolella Tr. (Lep.: Phycitidae). There were indications that Form B and C of the skeletonweed would continue to spread and eventually fill the vacant niche left by Form A. Another strain of the skeletonweed rust has been recently introduced and it attacks only Form B. Other organisms are through to be necessary to control Form C (Wells 1970, Wapshere et al. 1974, Groves & Cullen 1977, Burdon et al. 1981, Cullen & Moore 1983).

In summary, the biological control of rush skeletonweed, Chondrilla juncea L. in Australia was the first project to involve the intentional international transfer of a phytopathogen for the biological control of a plant, i.e., the rust fungus Puccinia chondrillina Bubak & Sydenham (Uredinales) between Italy and Australia in 1971 for the successful biological control of a noxious plant (Goeden & Andrés 1999). This project also was one of the first to target a plant pest of cropland (dryland wheat). It established procedures for testing phytopathogens for host specificity under quarantine conditions and involved the first intentional importation in 1971 of a phytophagous mite, Eriophyes chondrillae for biological control (Cullen 1974, 1978).

REFERENCES: [Additional references may be found at: MELVYL Library ]

Burdon, J. J., R. H. Groves & J. M. Cullen. 1981. The impact of biological control on the distribution and abundance of Chondrilla juncea in south-eastern Australia. J. Appl. Ecol. 18: 957-66.

Cullen, J. M. 1974. Seasonal and regional variation in the success of organisms imported to combat skeleton weed Chondrilla juncea L. in Australia, p. 111-17. In: A. J. Wapshere (ed.), Proceedings of the III International Symposium on Biological Control of Weeds, 1973, Montpellier, France.

Cullen, J. M. 1978. Evaluating the success of the programme for the biological control of Chondrilla juncea in Australia, p. 233-39. In: T. E. Freeman (ed.), Proceedings of the IV International Symposium on Biological Control of Weeds, 1976, Gainesville, Florida.

Cullen, J. M. & A. D. Moore. 1983. The influence of three populations of Aceria chondrillae on three forms of Chondrilla juncea. J. Appl. Ecol. 20: 235-43.

Goeden, R. D. & L. A. Andrés. 1999. Biological control of weeds in terrestrial and aquatic environments. In: Bellows, T. S. & T. W. Fisher (eds.), Handbook of Biological Control: Principles and Applications. Academic Press, San Diego, New York. 1046 p.

Groves, R. H. & J. M. Cullen. 1977. Chondrilla juncea: the ecological control of a weed, p. 7-17. In: Kithing & Jones (eds.), The Ecology of Pests. CSIRO, Australia. 253 p.

Wapshere, A. J., S. Hasan, C. K. Wahba & L. Caresche. 1974. The ecology of Chondrilla juncea in the western Mediterranean. J. Appl. Ecol. 11: 783-800.

Wells, C. J. 1970. The ecology and control of skeleton weed (Chondrilla juncea) in Australia. J. Aust. Inst. Agric. Sci. 37: 122-37.