• The Plant Pathology Journal
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• v.24 no.1
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• pp.67-73
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• 2008

Seedling damping-off and bottom rot caused by Rhizoctonia solani are yield limiting diseases of crisphead lettuce. To provide biocontrol measure in the management of the diseases, biocontrol strain Pseudomonas aeruginosa LY-11 was isolated from lettuce rhizosphere and introduced into crisphead lettuce rhizosphere by the seed coating delivery method. Alginate was used as a coating material to generate beads containing $10^6-10^{6.5}$ colony-forming units (CFUs) of viable bacterial cells of LY-11. When seeds germinated from the alginate beads containing the strain LY-11, the bacteria established mostly in plant rhizosphere to maintain at least $10^4$ CFU per gram of plant tissues. Crisphead lettuce seedlings germinated from the entrapped seeds were less affected from damping-off and bottom rot with disease control values of 70.4% and 85.4% respectively. Although P. aeruginosa LY-11 colonized plant rhizosphere and not phyllosphere, the result indicated that bottom rot caused by the foliar inoculation of R. solani was effectively reduced by the rhizobacteria. All data suggested that immobilized rhizobacterial application in seeds by alginate coating could control damping-off and induce induced systemic resistance of crisphead lettuce to reduce bottom rot.

• Journal of Bio-Environment Control
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• v.7 no.1
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• pp.35-41
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• 1998

This experiment was conducted to find out the effect of artificial light sources(high-pressure sodium lamp, metal halide lamp and fluorescent lamp) on growth of crisphead lettuce(Lactuca sativa L.) in a plant factory. No significant differences in leaf fresh and dry weight were presented among them. Lettuce plants grown under fluorescent lamp showed the lowest growth. Considering the growth of lettuce and efficiency of lamps, it is worth using HPS(high-pressure sodium) lamp in plant factories. The leaves of lettuce plants grown under artificial light sources showed tipburn symptoms at 14th day after transplanting. The beginning of tipburn symptom have been seen on the ninth to tenth leaves from the cotyledons. It is estimated that the occurrence of tipburn was related to rapid growth and K uptake of the lettuce Plants. The Ca, Mg. Cu and Zn elements tended to be accumulated in the nutrient solutions but the T-N, P, Fe and Mn elements keep in balance in them.

• Korean Journal of Agricultural Science
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• v.50 no.4
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• pp.713-721
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• 2023

Soil acidification challenges global food security by adversely influences soil fertility and agricultural productivity. Carbonized agricultural residues present a sustainable and ecofriendly way to recycle agricultural waste and mitigate soil acidification. We evaluated the effects of organic amendments on lettuce growth and soil chemical properties in two soils with different pH levels. Carbonized rice husk was produced at 600℃ for 30 min and rice husk was treated at 1% (w·w^-1). Carbonized rice husk increased soil pH, electrical conductivity, total carbon content, and nitrogen content compared with untreated and rice husk treatments. Furthermore, this study found that lettuce growth positively correlated with soil pH, with increasing soil pH up to pH 6.34 resulting in improved lettuce growth parameters. Statistical correlation analysis also supported the relationship between soil pH and lettuce growth parameters. The study findings showed that the use of carbonized rice husk increased the constituent elements of lettuce, such as carbon, nitrogen, and phosphate content. The potassium content of lettuce followed a similar trend; however, was higher in acidic soil than that in non-acidic soil. Therefore, improving the pH of acidic soil is essential to enhance agricultural productivity. It is considered advantageous to use agricultural residues following pyrolysis to improve soil pH and agricultural productivity.

• Korean Journal of Ecology and Environment
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• v.47 no.1
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• pp.32-40
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• 2014

This study was conducted to evaluate the growth response of economical six leafy vegetables that are crown daisy, pak-choi and four kinds of lettuce (Red leaf lettuce, Green leaf lettuce, Head lettuce, Romaine lettuce) by light treatment of LED in plant factory. The light treatments were composed of red, blue, red+farred, red+blue, red+blue+white LEDs, irradiation time ratio of the red and blue LED per minute (1 : 1, 2 : 1, 5 : 1, 10 : 1), and duty ratio of mixed light (100%, 99%, 97%). The following results were obtained in different LED light sources treatments: Shoot biomass and S/R ratio of romaine lettuce were the highest under mixed red+blue LEDs. S/R ratio of head lettuce was higher under mixed red+blue+white LEDs than red+blue LEDs. The others showed no difference in LED light treatment. Shoot biomass, total biomass and S/R ratio of green lettuce, head lettuce and pak-choi were highest in the higher red ratio (5 : 1) on irradiation time of red : blue LED ratios. By the different duty ratio (red+blue and red+blue+white LEDs), Under the mixed light of red+blue, shoot and root biomass of crown daisy and romaine lettuce were high in duty ratio of 100% and 99%, and S/R ratio was highest in all the 6 kinds in duty ratio of 97%. All the 6 kinds showed a fine growth state in low duty ratio (97%). Green lettuce, romaine lettuce and pak-choi showed relatively high shoot biomass and total biomass in low duty ratio of 97% under the mixed light of red+blue+white. S/R ratio of romaine lettuce and head lettuce were highest in the duty ratio of 97% with red+blue+white LEDs. Thus, we can cultivate stably without reference to external factors, if we use appropriate light sources and light quality in closed-type plant factory.

• Journal of Life Science
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• v.8 no.2
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• pp.131-136
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• 1998

Tje dispersion and adaptation of the recently immograted plant, prickly lettuce (Lactuca serriola), were studied. The distribution of prickly lettuce was limited to south of the central districts of the Korean peninsula. The distrbution range is being diffused contimnuously by manual transportation. The 10 selected sites showed typical road side vegetation of an early successional stage; tje quadrats had 90% herbaceous cover, 5% shrub cover, and no tree cover. Dominant species were Kummerowia stipulacea, Ixeris chinensis, Ambrosia artemisiifolia, Lactuca indica, Toungia sonchifolia, Cephalonoplos segetum, Rubus parvifolius, Izeris polycdphala, Hemistepta lyrata, Cercis chinensis Artemisia capillaris. The investigated sites were divided into 4 patterns based on vegetation with high dissimilarity. The presence of mant patterns, despite high livels of differences, indicated that the characteristic prickly lettuce communities were not yet formed.

• Korean Journal of Organic Agriculture
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• v.8 no.1
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• pp.131-137
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• 1999

This study was conducted to investigate the effects of microbial fertilizers on the yields of Leaf lettuce, chemical components of soil, and the microbial floras. Six micriobial fertilizers, MPK+Husk+Palma, Husk+Palma, MPK+Compost, Compost, Bio livestock cattle system(BLCS) cattle dropping, and Tomi, were used. All of the microbial fertilizers were tend to increase yields of Leaf lettuce, especially MPK+Husk+Palma treatment was most effective. In a chemical components of soil, concentrations of K, Mg were increased with Tomi treatment, however, the other concentrations of soil chemical components were not different. In a microbial floras of soil, Tomi, Husk+Palma, and MPK+Husk+Palma treated plots increased in numbers of total bacteria and bacillus. Tomi treated plot increased in numbers of actinomycetes and fungi, also. The other microbial floras of soil were not different, however. The microbial fertilizers may affect the useful microbial floras, therefore, it would be increase yield of Leaf lettuce treated with them.

• Korean Journal of Organic Agriculture
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• v.12 no.4
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• pp.427-436
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• 2004

This study was conducted to investigate the effect of microbial product on microorganisms in soil and the growth of leaf lettuce. The test material were treated with chitosan, wood vinegar and EM activity liquid, and treatment concentration was 50 times solution and 100 times solution level with foliar application. The results were summarized as follows : Among foliar application of microorganisms treatments diluted by chitosan 100 times solution level was effective considering growth of leaf lettuce as compared other dilutions and control plot. Change of microorganism number in the soil for cultivation of chinese cabbages and leaf lettuce was increased with microorganism treatment plot as compared with control plot. Specially chitosan 100 times solution level showes the most significant effect.

• The Korean Journal of Mycology
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• v.51 no.3
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• pp.245-249
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• 2023

Prickly lettuce (Lactuca serriola), an invasive annual plant, poses a significant threat to the agricultural systems of many countries, including Korea. In 2020, leaf blight symptoms were observed in the prickly lettuce populations of various farms across Korea. Detailed morphological and molecular sequence analyses revealed that the disease was caused by the fungus, Curvularia intermedia. A pathogenicity test confirmed that the fungus can cause the same symptoms in healthy prickly lettuce, thereby fulfilling Koch's postulates. To the best of our knowledge, this is the first report of C. intermedia causing leaf blight on L. serriola in Korea, suggesting its potential as a biocontrol agent for this weed. However, further investigations are necessary to determine its ecological impact to prevent any non-target effects.

• Korean Journal of Environmental Agriculture
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• v.19 no.3
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• pp.223-227
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• 2000

Absorption of Cadmium(Cd) and Arsenic(As) by lettuce following to the change of polyamine content in lettuce were examined to find the effect of these elements on lettuce growth and on the basic resistance mechanism. As the contents of Cd and As were increased in soil, the contents of these elements were significantly increased in lettuce but lettuce growth was decreased. Sequential fractionation experiment of the Cd and As treated soil was shown that exchangeable, dilute acid extractable, and organically bound form, which were more mobile and phyto-available, of Cd were increased by 5.6, 42.9, and 56.7% during a growing season whereas 17.6, 25.0, and 24.1% were increased in case of As, respectively. Specially, the Cd content of leaves and roots in lettuce was positively correlated with exchangeable, dilute acid extractable, and residual form of Cd in the treated soil. However, the As content of roots in lettuce was positively correlated with all chemical forms of As in the treated soil. The contents of putrescine and cadaverine, a kind of polyamine, were also increased in lettuce as both elements were increased in soil.

• The Korean Journal of Mycology
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• v.40 no.4
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• pp.271-276
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• 2012

A mycoparasite, Paraconiothyrium minitans CM2 was selected for biological control of sclerotinia rot of lettuce caused by Sclerotinia sclerotiorum. The experiment was carried out in a lettuce greenhouse in Yangpyeong from March to April.. When lettuce sclerotinia rot showed in the early stage of occurrence, Conidial suspension of the mycoparasite was weekly treated once to three times onto soil surface around lettuce plants. Incidence of sclerotinia rot in the once-application plot of the mycoparasite ($1{\times}10^7$ spores/$m{\ell}$) and in the benomyl(WP)-treated plot was 11.0% and 2.7%, respectively, whereas that of control was 31.0%. Incidence of twice- and three-application plots of the isolate was 7.9% and 12.8%, respectively. For increasing the effect of the mycoparasite, the experiment for the timing of application of P. minitans CM2 was carried out in a lettuce greenhouse in Yangpyeong and Suwon. Control efficacy against lettuce sclerotinia rot in the soil-drenching plots of P. minitans CM2 ($5{\times}10^6$ spores/$m{\ell}$) in the planting was 75.3~84.7%, and control effect by treatment of the isolate at the pot drenching+the soil-drenching plots in the early stage of disease occurrence was 63.8~58.0%. As the results, P. minitans CM2 could be a prospective biofungicide for biological control of sclerotinia rot of lettuce.