• Korean journal of applied entomology
• /
• v.51 no.4
• /
• pp.411-419
• /
• 2012

The lure-distance of Riptortus pedestris aggregation pheromone was elucidated and the damage mitigation effect by mass trapping of R. pedestris was examined in commercial soybean fields. The recaptured ratio showed that 76.1% of total recaptured individuals were lured within 40 m and 89.0% of total recaptured adults were arrested in the lower 80 m. There is not much difference in the number of recaptured individuals according to the location of installed traps in the experiment. There was linear correlation between the total installed number of traps and the total number of trapped individuals in commercial soybean fields. and the highest yield (261.8 g/10 stems) was investigated in the field that had installed a pheromone trap per $770m^2$. No relationship wasf found between the covered areas of a pheromone trap for mass trapping and yield loss. The ratio of type A seed (healthy) was higher in the field that installed a trap per $385m^2$ and $770m^2$ (around 62%) and type B seed (showing distinct injury marks) was lower in the same fields (around 27%). From this result, we could reduce slightly the damage of soybean seeds by the mass trapping of Riptortus pedestris adults with an aggregation pheromone trap per $385{\sim}770m^2$ area range.

• Journal of The Korean Society of Grassland and Forage Science
• /
• v.41 no.2
• /
• pp.77-83
• /
• 2021

Rye (Secale cereal L.) is the most tolerant to abiotic stress including low temperature, drought, and unfavorable soil conditions among the winter cereals. Rye is the rapid growth of early spring results from increasing areas for the use of the forage and green manure in the middle part of Korea. "Jungmo2509", a rye cultivar was developed by the National Institute of Crop Science (NICS), RDA in 2014. It was developed from a cross between "Olhomil", a self-compatible cultivar, and "Synthetic II", a self-incompatible line. "Jungmo2509" is an erect plant type and of a middle size, with a green leaf color, a yellowish-white colored culm, and a yellowish brown-colored, small-size grain. The heading date of "Jungmo2509" was April 23, which was 5 days later than that of "Gogu", respectively. But "Jungmo2509" showed greater resistance to lodging compared to that of the check cultivar, with similar to winter hardiness, wet injury, and disease resistance. "Jungmo2509" was a higher to than "Gogu" in terms of protein content (9.4% and 8.0%, respectively), total digestible nutrients (TDN) (55.7% and 55%, respectively). The seed productivity of "Jungmo2509" was approximately 2.08 ton 10a-1, which was 11% lower than that of the check. Almost all rye cultivars are out-crossing due to genes controlling incompatibility, but "Jungmo2509" is higher seed fertility (56%) than that of Gogu (0%). it has self-compatible genes. "Jungmo2509" is erect in plant type and resistance for lodging. Therefore, "Jungmo2509" can produce uniform seeds for processed grains of human consumption and utilize them as parents for breeding the rye hybrids with high forage yields.

• Korean Journal of Environmental Agriculture
• /
• v.13 no.3
• /
• pp.271-278
• /
• 1994

Mode of safening action of N-(4-chlorophenyl)maleimide (CPMI) on metolachlor [2-chloro-N-(2-ethyl-6-methylphenyl)-N-(2-methoxy-l-methylethyl) acetamide] was investigated in sorghum(Sorghum bicolor L.). CPMI was synthesized by dehydration of N-(4-chlorophenyl)maleamic acid (CPMA) which was obtained from amination with maleic anhydride and 4-chloroaniline. Melting points of CPMA and CPMI (>95% purity) were $200-202^{\circ}C$ and $116-118^{\circ}C$, respectively. Growth response study indicated that seed treatment of CPMI increased tolerance of sorghum shoot to metolachlor approximately threefold. Sorghum shoot was more sensitive to injury caused by metolachlor and CPMI activity than the root. Metolachlor was initially absorbed by sorghum shoot and metabolized to the metolachlor-glutathione conjugate in CPMI-untreated and treated shoots. However, CPMI treatment significantly accelerated metabolism of $[^{14}C]$metolachlor in sorghum shoot, resulting in decrease in metolachlor content and increase in formation of the glutathione conjugate. It was concluded that the protection against metolachlor injury conferred by CPMI appeared to be correlated to detoxification of metolachlor in sorghum shoot tissue.

• Korean journal of applied entomology
• /
• v.45 no.3 s.144
• /
• pp.333-337
• /
• 2006

The damage aspects of soybean by common cutworm, Spodoptera litura (Fabricius) (Lepidoptera: Noctuidae) at different larval density and different growth stage of soybean were studied in soybean field. The percent yield reduction(Y) of soybean infested by different densities of S. litura (X, no. of larvae/plant) under outdoor conditions for a three week period were estimated by the following equations: (1) Y = 1.655X - 6.025 ($R^{2}=0.952$) for the R1 (flowering stage); (2) Y = 0.725X - 0.475 ($R^{2}=0.986$) for the R3 (beginning pod stage); and (3) Y = 0.635X - 1.325 ($R^{2}=0.986$) for the R5 (beginning seed stage). Based on the relationships between the densities of S. litura larvae and the yield index of soybean, the number of larvae (2nd-3rd instar) which caused 5% loss of yield (Tolerable injury level) was estimated to as approximately 6.7 for the R1, 7.5 for the R5, and 10.0 per plant for the R5, respectively. Average soybean leaf areas consumed by 1st, 2nd, 3rd, 4th, 5th and 6th larvae of Spodoptera litura during 24 hr at $28^{\circ}C$ was 0.3, 0.7, 2.6, 4.0, 20.1, and $55.8\;cm^{2}$, respectively.

• Journal of Plant Biology
• /
• v.11 no.1
• /
• pp.7-14
• /
• 1968

Buckwheat seeds produced in previous year (1965) in an experimental pot culture in which nine levels of P-32 ranging from $1.4{\times}10-4 to 3.3{\times}104$\mu$c/pot(as of 27 July 1965)$, with the same specific activity, had been applied to the corresponding pots respectively, were used this year(1996) in water and soil culture as well as in germination test to investigate the feature and extent of possible residual effects of P-32 incorporated upon germination and plant growth, and the following results were obtained: 1. Under the given experimental conditions both stimulative and inhibitory effects of radiation were observed. 2. The germination rate of the seeds was lower at the higher level of P-32 aplication ranging from $3.0{\times}103 to 3.3{\times}104$\mu$c/pot$ and higher at 0.2 $\mu$c P/pot than the control. 3. Among the seeds produced at the higher level of application about 80% was failed to germinate, owing to the radiation injury. The remaining 80% was failed to germinate, owing to the radiation injury. The remaining 80% survived the damaging effect and showed vigorous growth and increased yield. The latter group of seeds thus proved themselves to be more radioresistant than the former. 4. The survived seeds produced later more straw and root on dry weight basis. The higher the level of P-32 applied, the stronger the stimulative effect showed in vegetative growth. 5. No radiation effect on linear growth of the plants was observed in the soil culture. 6. The dry weight of straw produced showed little difference at the moderate range compared with that of control in the soil culture. At high level of application, i.e. over $\mu$c P32/pot, however, the production was increased by 12-37% of control. 7. As for the dry weight of root harvested, the P-32 treatment over 24$\mu$c P32/pot produced 82-155% more than the control, whereas little difference was observed under 2.2$\mu$c P32/pot. 8. The seed production increased in general by the P-32 treatments. Particularly at the moderate level of application the rate of increase amounted to 70% of the control. 9. Those individual plants which survived damaging effects of radiation at the germinating stage shwoed remarkable stimulative effects both in vegetative and in reproductive stage of growth.

• Korean Journal of Agricultural Science
• /
• v.38 no.2
• /
• pp.191-198
• /
• 2011

Herbicidal effects and crop selectivity of aqueous leaf extracts of sorghum (Sorghum bicolor L.) were evaluated against several weed species for developing sustainable weed management in organic farming. Aqueous sorghum leaf extracts were highly phytotoxic to different weed species. No broadleaf weeds were germinated in the concentration of 5 fold or higher concentrated sorghum leaf extracts and 90% of seed germination was inhibited within that range in grass species. Sorghum leaf extracts strongly inhibited the growth of different weeds by pre-emergence and foliar applications in greenhouse condition. Foliar application of sorghum leaf extracts had a higher inhibitory effect than the pre-emergence application. Broadleaf weed species were more susceptible than grasses to the application of sorghum leaf extract in foliar applications than grasses. Galium spurium, Erigeron candensis, and Rumex japonicus were completely killed at the highest concentrated sorghum leaf extract both in pre-emergence and foliar application. Most broadleaf weed species were inhibited more than 80% at pre-emergence application at 50 fold concentrated sorghum leaf extract. G. spurium, E. candensis, R. japonicus, Eclipta alba, Plantago asiatica and Portulaca oleraeea were most susceptible to sorghum leaf extract in foliar application. Growth of most broad leaf weed species was suppressed by greater than 90% at 50 fold concentrated sorghum leaf extract. Most crop species were tolerant to sorghum leaf extract but shoot growth was slightly reduced by the application of 40~50 fold concentrated extracts, Sorghum leaf extract may used to control weeds in organic fanning without affecting the growth of crop.

• Journal of Ecology and Environment
• /
• v.33 no.2
• /
• pp.121-131
• /
• 2010

Betula platyphylla var. japonica and Betula ermanii segregate vertically at an elevation of approximately 1,850 m on Mt. Neko in Nagano Prefecture, Japan. B. platyphylla var. japonica and B. ermanii were the dominant species below and above this altitude, at which the mean-annual and growing-season air temperatures were $4^{\circ}C$ and $14.1^{\circ}C$, respectively. Based on a modification of Kira's warmth index which employs cumulative temperature represented as $^{\circ}C$ day, leaf unfolding in both species was observed to be initiated at $58^{\circ}C$ day and $169^{\circ}C$ day, respectively. In 1996, leaf unfolding was initiated on 18 May in B. platyphylla var. japonica (+/-6 days) and on 5 June in B. ermanii (+/-8 days), shortly after the last frost which occurred on 5 May 1995 above 1,850 m; below this elevation there was no risk of frost at the time. At elevations above 1,850 m, the unfolded leaves of B. platyphylla were damaged by late frost, while B. ermanii escaped injury because the leaves were still protected by winter buds. The optimum temperature for seed germination in both B. platyphylla and B. ermanii was $30^{\circ}C$. Temperature alternation from 10 to $30^{\circ}C$ and moist storage of seeds at $4^{\circ}C$ (stratification) prior to incubation increased germination rates in both species. The seedlings of B. ermanii had a greater survival rates than those of B. platyphylla var. japonica when planted above 1,850 m. Comparisons of the timing of leaf unfolding and the latest frost at a site appeared to be the main factors affecting the vertical distribution of these species.

• Research in Plant Disease
• /
• v.19 no.3
• /
• pp.196-200
• /
• 2013

This study was carried out to investigate yield loss due to soybean leaf spot disease caused by Cercospora sojina Hara and to determine the economic threshold level. The investigations revealed highly significant correlations between disease severity (diseased leaf area) and yield components (pod number per plant, total grain number per plant, total grain weight per plant, percent of ripened grain, weight of hundred seed, and yield). The correlation coefficients between leaf spot severity and each component were -0.90, -0.90, -0.92, -0.99, -0.90 and -0.94, respectively. The yield was inversely proportional to the diseased leaf area increased. The regression equation, yield prediction model, between disease severity (x) and yield (y) was obtained as y = -3.7213x + 354.99 ($R^2$ = 0.9047). Based on the yield prediction model, economic injury level and economic threshold level could be set as 3.3% and 2.6% of diseased leaf area of soybean.

• Korean Journal of Plant Resources
• /
• v.15 no.3
• /
• pp.211-215
• /
• 2002

This study was carried out to select fungicides which are effective for the control of anthracnose disease of Carthamus tintorious L. caused by Cottetotrichum acutatum. Eive chemicals, i.e., thiophanate-methyl$.$triflumizole, iminoctadinetris$.$thiram, metiram, bitertanol$.$propineb, metalaxyl$.$dithianon were treated to Cheongiu native variety for the test of control effect. The results obtained were summarized as the follows; No. of harvested plants per ㎡ was most in iminoctadinetris$.$thiram and its value showed 21.2 compared with 16.8 in control. Iminoctadinetris$.$thiram and metiram were most effective to control the disease and their contyol values were 57.2%, and 49.4%, respectively. Chemical injury of five chemicals was not occurred at the double-diluted solution treatment. Seed yield was 47∼48% higher in iminoctadinetris$.$thiram and metiram than 75 kg/10 a in control.

• Journal of Korean Society of Forest Science
• /
• v.81 no.1
• /
• pp.30-39
• /
• 1992

Artificial acid rain(pH2.0, 3.0, 4.0 and 5.0) was treated on the seeded pots of 4 species to examine its effects on germination, leaf injury and seedling growth. Aluminum ammonium sulfate solution (0.5, 1.0 and 2.5mM) and artificial acid rain (pH3.0, 4.0 and 5.0) were treated on the seeded germinators of 3 species to examine its effects on germination and radicle growth. Artificial acid rain was prepared by diluting sulfuric acid with ground water and ground water(pH6.5) was used as control. Artificial acid rain was sprayed to seeded pots three times per week. About 5mm of artificial acid rain was treated each time from early April to early October, 1991. Germination, seedling establishment, radicle growth, leaf injury and seedling growth were measured and compared among the treatments. The results were summarized as follows 1. Germination, seedling establishment rate of Pinus densiflora were highest on the pH5.0 pot whereas those of Ailanthus altissima was highest on the control pot, and those of Magnolia sieboldii showed the highest value on the pH3.0 pot. 2. The differences in seedling height of Pinus densiflora and Pinus rigida were significant among the treatment levels of acid rain, whereas those of Magnolia sieboldii and Ailanthus altissima were not significant. Seedling heights of Pinus densiflora and Pinus rigida were highest on the pH3.0 pot, and that of Magnolia sieboldii was highest on the pH4.0 pot, and that of Ailanthus altissima was highest on the control pot. 3. Seedling dry weights of Pinus densiflora. Pinus rigida, and Ailanthus altissima differed significantly among the treatments, but that of Magnolia sieboldii did not differ. Highest seedling dry weights of Magnolia sieboldii and Ailanthus altissima were observed on the pH4.0 pot, and that of Pinus densiflora was observed on the pH3.0 pot, and that of Pinus rigida was observed on the pH5.0 pot. 4. With decrease of pH value of artificial acid rain, the number of injured needle and injured individual tended to be increased. 5. The differences in effects of soil acidity were highly significant among the treatments for all species. 6. Radicle growth of Pinus densiflora differed significantly among pH levels and aluminum concentrations.