Volume 38(3,4), 1999 
53 
Biocontrol of Yellow Himalayan 
Raspberry: Exploration in China 
Donald E, Gardner 
Pacific Island Ecosystems Research Center, 
Biological Resources Division, 
U. S. Geological Survey 
Department of Botany, University of Hawaii at Manoa 
Honolulu, Hawai*i 96822 
Abstract: Yellow Himalayan raspberry (YHR) (Rubus eUipticus var. obcordatus) is a noxious 
bramble in Hawai'i targeted for biocontrol research. Earlier literature searches were focused on the 
occurrence of natural enemies in its putative native habitats: the Himalayan foothills of northern 
India. Facilitated by a cooperative agreement with Chinese scientists, we have undertaken recent 
field surveys in provinces of southern and central China, also part of YHR's range. YHR was found 
at several sites, representing diverse habitats, in Yunnan and Sichuan Provinces. Notwithstanding its 
apparent wide geographical distribution, YHR was neither locally common nor appeared as vigorous 
in growth as in Hawai'i. Numerous insects and a rust fungus, but few other pathogens were 
associated with YHR. Work is underway in China to determine which of the insects are sufficiently 
host specific for further testing in Hawai*i. 
Rubus ellipticus Sm., which is widely grown as 
an ornamental in warm regions, is classified in 
series Elliptici, section Idaeanthi, subgenus 
Idaeobatus (Focke, 1910). Two varieties of R. 
ellipticus, distinguished by their leaf shape, are 
recognized: R. ellipticus var. ellipticus and R. 
ellipticus var. obcordatus, the variety known in 
Hawai'i as yellow Himalayan raspberry (YHR), 
YHR was introduced, presumably for use in plant 
breeding programs, to the Volcano Agricultural 
Experiment Station and has since spread from this 
site. It was first collected as an escapee from 
cultivation in 1961, and has become naturalized 
locally in the Volcano, and regions similar habitat 
on the island of Hawai'i in mid-elevation forests 
(1,060-1,220 m elevation) (Jacobi and Warshauer, 
1992; Stratton, 1996; Wagner etal., 1990). 
YHR has been designated a noxious weed by the 
state of Hawai'i. In infested lands, it forms 
impenetrable thickets of heavily armed growth, to 
4 or more meters high. At present, the greatest 
infestation is locally centered in the Volcano 
community adjacent to Hawai'i Volcanoes 
National Park (HAVO), but spread is thought to be 
inevitable. In contrast with Hawai'i's several other 
introduced bramble species, R. ellipticus is 
relatively shade tolerant and has the ability to 
invade and become established in undisturbed 
forest under stories. In such sites where it has 
become established, little other vegetation has been 
observed growing under or near R. ellipticus 
(Stratton, 1996). Whether this is due to the 
increased shading or whether R. ellipticus has 
allelopathic qualities has not been conclusively 
determined. 
The fleshy fruit of R. ellipticus is readily 
consumed by birds, which in turn distribute the 
seeds. There is generally little doubt that, in time, 
R. ellipticus has the ability to become widely 
established throughout the islands (Gerrish et al., 
1992). Resource managers and landowners 
consider mechanical or chemical means of control 
