Ecology Distribution Management Info Impact Info References and Links Contacts

Management Information Rubus discolor is a difficult species to control because of its extensive vegetative reproduction and because it often grows in very sensitive wetland habitats. This species is shade-intolerant, so planting fast-growing shrubs or trees may prevent reestablishment. Resprouting is problematic, and many years of follow-up efforts are necessary for control. Plants can be eliminated by grubbing with follow-up treatment a year later, repeated mowing, and by pasturing with goats. Goats eat blackberries readily, and seem to prefer them to other plants. An economic analysis in Australia showed that running goats on a blackberry-infested pasture was cheaper than using herbicides to manage the berries. (Alaska Natural Heritage Program, 2005; Cox, 2003; and Francis, UNDATED). Chemical: Research has shown that the herbicides picloram, 2,4,5 T, and a combination of aminotriazole & ammonium thiocyanate are effective at controlling R. discolor (Amor, R.L., 1972). Fechtig and Furtick (1964) assesed the efficacy of various herbicides on R. discolor and found that only picloram at rates 2 lb./acre gave complete control of R. discolor on assessment 5 months after treatment. Lower rates of picloram (1 lb./acre) gave 95 % control, while 2,4,5 T at 1, 2 and 4 lb./acre gave respectively 75, 85 and 93 % control. Foliar application of Trichlopyr amine at 2% effective, as is cut stump af Trichlopyr amine at 100%, especially as primocanes emerge (Oppenheimer pers.comm., 2006). Biological: A highly virulent strain of Phragmidium violaceum (bramble leaf rust) from central France has shown to offer some evidence of specificity; being effective on R. discolor. The infection weakens growth and reduces the rate of spread of the weed, making it more manageable. The State of Victoria in Australia has investigated and approved blackberry as a candidate for biological control by Phragmidium violaceum. Unfortunately results so far show the program as being unsuccessful because the rust has not caused significant damage to its host. In the United States, the introduction of herbivorous insects and fungi to control R. discolor is not supported by USDA because of the risk posed to commercially important Rubus species (Alaska Natural Heritage Program, 2005; DiTomaso, 2006; Dodd and Lloyd, 1992; and Parsons et al. 1984). Biological control in Hawai`I should be discouraged without rigorous testing because of 2 endemic Rubus spp. (R. hawaiiensis, and R. macraei), the latter restricted to high elevations on East Maui and Hawai`i Islands, and considered rare (Oppenheimer pers.comm., 2006).          Location Specific Management Information Australia Control measures include heavy grazing in autumn to prevent cane tip rooting, several foliage spray applications of picloram, 2,4,5 T or aminotriazole + ammonium thiocyanate in summer or picloram granules applied in late winter (Amor, R.L., 1972). Goats have a long history of use for blackberry control, particularly in Australia and New Zealand where they have been used since the 1920s. Goats eat blackberries readily, and seem to prefer them over other plants. An economic analysis in Australia showed that running goats on a blackberry-infested pasture was cheaper than using herbicides to manage the berries (Cox, 2003). Maui Is. (United States (USA)) R. discolor plants on East Maui have been treated with a 10% Garlon 4 in oil basal stem method (Starr et al. 2003). New Zealand Goats have a long history of use for blackberry control, particularly in Australia and New Zealand where they have been used since the 1920s. Goats eat blackberries readily, and seem to prefer them over other plants. An economic analysis in Australia showed that running goats on a blackberry-infested pasture was cheaper than using herbicides to manage the berries (Cox, 2003).          Management Resources/Links 1. Alaska Natural Heritage Program. 2005. Himalayan blackberry - Rubus discolor Weihe & Nees. Environment and Natural Resources Institute: University of Alaska Anchorage. 2. Hoshovsky, M. 1989. Element Stewardship Abstract for Rubus discolor, (Rubus procerus). The Nature Conservancy.         Summary: Available from: http://www.ipm.ucdavis.edu/PMG/PESTNOTES/pn7434.html [Accessed 15 March 2006]          Results Page: 1