• Korean Journal of Weed Science
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• v.14 no.2
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• pp.120-127
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• 1994

To establish an efficient herbicide screening method for purple nutsedge(Cyperus rotundus) control, its sprouting characteristics, tuber production and responses on several herbicides were investigated under greenhouse condition. The tubers stored at $4^{\circ}C$ after sterilization with the diluted prochloraz(Spotac) solution showed higher sprouting than the non-sterilized did. The harvested tubers were not dormant, and the sterilized tubers which stored at low temperature had a sprouting capability of about 80% after 6 months. If the fresh weight of purple nutsedge tubers was decreased to below 48%, they could not sprout. However, the tubers soaked in water and then stored at low temperature could sprout by 88% even 6 months later. Sprouting and initial growth of tuber were much better at $35^{\circ}C$-day/$25^{\circ}C$-night than at 30/$20^{\circ}C$ or 25/$15^{\circ}C$. The half-sected tubers, which were prepared by setting the intact tuber of above 1.2g latitudinally, were shown similar initial growth to the intact but those sected crucifically were not. These results suggest that the half-sected tuber itself can be used as a material on herbicide screening. About 1000 tubers could be harvested when 10 tubers planted in a pot($56{\times}35{\times}16cm$) filled with the artificial soil were cultivated in greenhouse of $35^{\circ}C$-day/$25^{\circ}C$-night for 3 months(April-July, 1993). Chlorimuron, Bentazon and Norflurazon were selected as the standards for the screening because of providing relatively effective control on purple nutsedge in both soil-surface and foliar spray treatment.

• Korean Journal of Weed Science
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• v.17 no.1
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• pp.1-9
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• 1997

The survey of weed community in paddy field was carried out to investigate the changes of weed species on 340 fields in Kyonggi Area in 1995, that is almost same condition as sampled in 1991. The weed species observed include 3 species of grasses, 5 species of sedges and 14 species of broadleaf and other weed. Herbicide treatment system in one time treatment vs more than two time treatment was 34:66 percentage. About 25 percentage among one time treatment system was used butachlor G. Ratio of annual weed vs perennial weed was 38:62, and then perennial weed ratio was high. Major dominant weed species were Sagitaria trifolia, Eleocharis kuroguwai, Echinochloa crus-galli, Bidens tripartita and Monochoria vaginalis. Weed occurrence was decreased as order of normal soil, poorly drained soil and saline soil. Dormant weed species were S. trifolia, E. kuroguwai, E. crus-galli and B. tripartita in normal soil and were S. trifolia, E. kuroguwai, E. crus-galli and Polygonium hydropiper in poorly drained soil, and were Scirpus planiculmis, S. trifolia and E. kuroguwai in saline soil. Weed occurrence was increased with delaying the transplanting time; dominant weed species were S. trifolia, E. kuroguwai, E. crus-galli and M. vaginalis in May transplanting field and were E. kuroguwai, S. trifolia, and C. serotinus in June transplanting field. Weed occurrence was decreased as order of non-plowing transplanting field, autumn plowing and spring plowing paddy field. Dominant weed species were S. trifolia, E. kuroguwai, E. crus-galli and M. vaginalis in autumn plowing, were S. trifolia, E. kuroguwai, E. crus-galli and B. tripartita in spring plowing, and were E. crus-galli, S. hotarui and S. trifolia in non-plowing transplanting field.