• Korean journal of applied entomology
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• v.31 no.2
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• pp.174-181
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• 1992

Early, mid, and late maturing soybean varieties were artificially infested with larvae of Delia platura at seeding, and then later development and productivity of soybeans were studied. In addition, in hope to utilize as possible tactics in the management of D. platura in soybeans, cultural factors such as contents of organic matter in soil, soil types, and the use of plastic mulching on the degree of damage to soybean plants by D. platura were examined. Primary leaf damage by the larva delayed the forthcoming vegetative growth but not the blooming which is initiated by the change in day length. Degree of delay in growth was more severe where leaf damage was induced by insect infestation than where artificially excised, apparently owing to simultaneous damage in stems and roots besides primary leaves. Productivity of soybeans also dropped significantly in plants with 25 % or more loss in the primary leaf area by the larva. Both transparent and black plastic mulchings shortened the period from seeding to emergence of soybean thus reducing the chance of possible attack by the larva. Soybean seedlings grown in clay loam or clay were attacked less by the larva than those in other types of soil. High organic matter content in the soil enhanced speed of emergence resulting in less larval damage to the seedling.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.27 no.3
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• pp.254-260
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• 1982

Ten soybean varieties were cultivated to know the varietal differences of lodging patterns of soybean plants under three different plant populations in two growing seasons in 1981. Lodging plant percentage was increased in higher plant populations and lodging responses to plant populations were different between soybean varieties. Lodging plant percentage was also increased by the growth of soybean plant and the patterns of lodging development along with the growth stages could be classified into four types by the varieties used, relatively lwoer iodging plant percentage from early to later growth stage but high in late and relatively high in middle stage but low in later stage. Williams, indeterminate type, and Kang-lim, determinate type, showed resistance to lodging under six different cultural practices, but Jang-yeop-kong, Dan-yeop-kong and Hwang-keum-kong showed resistance to lodging under specific cultural conditions among ten varieties used. Most of the plants lodged showed main stem bending in parts above first stem node in higher plant population and lodging resistant varieties showed lower frequency of stem bending lodging compared with those of lodging susceptible varieties.