Distribution of Exotic Weeds on Crop Fields in Jeju-do

Abstract

We surveyed the distribution of exotic weeds in the 141 crop fields of Jeju island. The exotic weeds were summarized as 66 taxa including 18 families, 50 genera, 64 species and 2 varieties. In winter crop fields there were 45 species of exotic seeds in 18 families, in summer crop fields 50 species in 16 families, and in perennial crop fields 39 species in 17 families. Total exotic weeds were classified to 39.4% of summer annuals, 36.4% of winter annuals, 7.6% of summer and winter annuals, and 16.7% of perennials. The ratio of summer annuals were high in the summer crop fields. Compositae was dominant family, followed by Gramineae, Malvaceae and Solanaceae. Malvaceae did not appear in perennial crop fields. Dominant exotic weeds in winter crop fields were Chenopodium album, Amaranthus viridis, Senecio vulgaris and Coronopus didymus, in summer crop fields, Chenopodium album, Amaranthus viridis, Senecio vulgaris and Sonchus oleraceus and in perennial crop fields, Conyza sumatrensis, Gnaphalium calviceps and Senecio vulgaris. The dominant exotic weeds in the crop fields of Jeju island were Chenopodium album, followed by Amaranthus viridis, Senecio vulgaris, and Conyza sumatrensis. This information could be useful for establishment of exotic weed control methods in Jeju island.

Modelling rice competition with Leptochloa fusca, Bidens frondosa and Ammannia coccinea in transplanted rice cultivation

“…Ammannia coccinea (L.), purple ammannia, is an exotic weed from North America. It is known to be a noxious alein weed in a rice paddy field for competition with rice in Korea (Jung et al, 2017;Kim et al, 2018). Hwang et al (2014) investigated its distribution and habitat types in Korea to obtain primary data for the management system of this species.…”

“…Bidens frondosa (L.), beggartick native to North America, is an invasive weed occurring in rice fields, moors, near cities, stream shores, field edges and roadsides. It is also being controlled as a troublesome alien weed in Korea as its range has expanded widely in all agricultural lands in all regions (Han et al, 2009; Kim et al, 2018). B. frondosa has an unusual pattern of invasion in rice fields.…”