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

• International Journal of Industrial Entomology and Biomaterials
• /
• v.8 no.2
• /
• pp.201-205
• /
• 2004

During the routine survey, the mortality of mulberry seedlings was noticed due to damping-off disease. The disease recognized by rotting of emerged seedlings near the soil line (just below the soil level) resulting in collapse of the seedlings. Two fungi were isolated from affected samples and identified as Alternaria alternata (Fr.) Keissler and Fusarium solani (Mart.) Sacc. Both the fungi were found to be responsible in causing pre and post emergence damping-off of seedlings in mulberry. For management of the disease, an experiment was conducted using fungicides. These fungicides were applied as seed treatment; soil drenching and foliar spray alone and in combination. Among the different treatments, integration of seed treatment and soil application of Dithane M-45 (Mancozeb 75% WP) + Bavistin (Carbendazim 50% WP) followed by foliar spray of these fungicides (after 35 days of sowing) resulted in better survivability of seedlings (93.3 %) on $90^th$ day and controlled the pre and post emergence damping off by 100 and 89.5%, respectively over the check.

• Journal of Ginseng Research
• /
• v.9 no.2
• /
• pp.163-169
• /
• 1985

The efficacy of fungicides was compared for control of root rot as well as leaf blight caused by Phytophthora cactorum on ginseng plants. Growth of P. cactorum in rlitro was completely or highly inhibited by metalaxyl, tetracyclin, captafol, carbendazim, and thiophanate + thiram. In field trials, the disease was significantly reduced not only in the root rot but also in the leaf blight when metalaxyl was applied at 4.17 mg a.i. per plant for soil drenching and 1.25 mg a.i. for foliage application. Also captafol was effective on control of the leaf blight but its effect was inferior to that of metalaxyl. Metalaxyl lost its effectiveness in vivo between the 5th and 7th week after soil wren ching. Phytotoxicity was, however, observed on 2 years old ginseng plants when metalaxyl was drenched at 8 mg a.i. while no phytotoxic symptom was developed on 2 years old ginseng plants at 4k mg a.i. and 3 years old at 16 mg a.i. per plant, respectively.

• Journal of Bio-Environment Control
• /
• v.24 no.3
• /
• pp.235-242
• /
• 2015

The objective of this study was to determine the effects of soluble potassium silicate by soil drenching application on watermelon growth, yield, and nutrient uptake. The potassium silicate rates were control (No potassium silicate), 1.63mM, 3.25mM, 6.50mM. The potassium silicate were treated 6 times (twice before fruit forming and 4 times after fruit forming per 7 day. Soil chemical properties, such as soil pH, EC, available phosphorus and silicate, exchangeable K, nitrate-N levels were increased after potassium silicate treatment, while the concentrations of soil organic matter, exchangeable Ca and Mg were similar to control. The growth characteristics of watermelon, such as stem diameter, fresh and dry weight of watermelon at harvest were thicker and heavier for increased potassium silicate treatment than the control, while number of node, and plant length were same for all treatments. With increased potassium silicate treatment, nutrient concentrations, such as P and K in the watermelon leaf at harvest were increased, N concentration in the leaf was decreased, and Ca and Mg concentrations in the leaf were same. Chlorophyll content was increased with increased potassium silicate application. The occurrence of powdery mildew was lower for the potassium silicate treatments than the control. Fresh watermelon weight for the potassium silicate treatments was 0.1 to 0.5kg per watermelon heavier than the control, sugar content was 0.5 to $0.6^{\circ}Brix$ higher than control, and merchantable watermelon was 2 to 4% increased compared to the control. These results suggest that potassium silicate application by soil drenching method in the greenhouse can improve watermelon nutrient uptake, merchantable watermelon and suppress the occurrence of powdery mildew.

• The Korean Journal of Pesticide Science
• /
• v.11 no.3
• /
• pp.186-193
• /
• 2007

Characteristics and control activity of copper hydroxide against pepper phytophthora blight caused by Phytophthora capsici were investigated in a greenhouse and a pepper field Copper hydroxide strongly inhibited the germination of zoosporangia and zoospores of P. capsici JHCS 2-5, showing $EC_{50}$ value by 0.6 and 0.3 ${\mu}g\;mL^{-1}$. With 1,040 ${\mu}g\;mL^{-1}$ of copper hydroxide in a greenhouse it showed 80% of the control value by soil-drenching application, while 16% by leaf-spraying. However, when it was treated enough to runoff to soil by leaf-spraying application with 50 ml per a pepper plant, it controlled a pepper phytophthora blight by 94.6 % of control value. Copper hydroxide showed a high protective activity at 1 and 3 days before application, while no curative activity. In a field it showed a high activity of 91%, when pepper plants were treated with copper hydorxide 4 times with a intervals of 10 days.

• The Plant Pathology Journal
• /
• v.23 no.1
• /
• pp.26-30
• /
• 2007

Phosphorous acid is known to effectively control various Oomycetes diseases. The phosphoric acid moves upward and downward through the xylem and phloem in plants. The sustainable forms of the slow releasing chemical in rhizosphere would be ideal to be up-taken by plants. Therefore, we developed a new system for phosphorous acid formulation using a carrier coated with polysaccharides. When the product was applied in rhizosphere, the adequate amount of phosphorous acid was consistently released up to 4 weeks in rhizosphere soils. While soil drenching with phosphorous acid at 1,000 ${\mu}g/ml$ and metalaxyl at 150 ${\mu}g/ml$ were not effective to control pepper Phytophthora blight for 4 weeks, direct application of our formulation product around basal stem of pepper plants resulted in excellent disease control effect against Phytophthora blight over 4 weeks. The application of 4 g of our product per plant was optimum to control the disease, and 8 g product/plant did not cause phytotoxicity. Based on the results, we conclude that the applications of the formulation product once or twice during cropping season can control Phytophthora diseases on various crops.

• Proceedings of the Korean Society of Plant Pathology Conference
• /
• 2003.10a
• /
• pp.96.1-96
• /
• 2003

Serratia plymuthim A21-4 strongly inhibits the mycelial growth, zoospore formation, and cystospore germination of Phytophthor spp and Pythium species. The bacterial isolate produced antifungal substance and chitinase. The bacteria also enhanced to plant growth remarkably in low nutritional condition. The application of cell suspension of A21-4 to pepper seedlings in greenhouse experiments and soil drenching in farmer's field was proved successfully to control the phythophthora blight of pepper. For the effective control, however, relatively high density of cell number(10$\^$9/cfu/$m\ell$) is required. Density effect was similar in plant growth promoting activity of A21-4. Though this investigation we improved the problem with changes of culture condition of bacteria and some nutritional amendment.

• Proceedings of the Korean Society of Crop Science Conference
• /
• 2022.10a
• /
• pp.53-53
• /
• 2022

Modem agricultural production needs to provide sustainable management practices that are eco-friendly and low cost. Plant extracts are a cost-effective and environmentally friendly alternative to synthetic plant growth regulators. This study was therefore carried out to investigate the effects of various plant extracts produced using different extraction methods on the vegetative growth of rice under laboratory and greenhouse conditions. For this study, seventeen plant extracts were made from plant species such as leaves of M. arvense, C. asiatica, M. oleifera, V. radiata, V. unguiculate, P. guajava, A. vera, and A. tuberosum, aboveground plant parts of C. rotundus, M. sativa, and P. frutescens, roots of R. undulatum, tubers of A. sativum, leaves and stems of G. max (cv. Taegwang) as well as rice straw and hulls (cv. Hopyeong). As a test crop, we applied these extracts to rice plants. For the purpose of making our extracts, some plant materials and species were collected in fields and others were purchased from Chonnam Hanyaknonghyup Cooperation (South Korea). Leaves, roots, and aboveground plant parts of plant species were dried, ground, extracted (water, boiling water and ethanol) and fermented. Rice growth promotion effects were determined using plant extracts at 0, 0.05, 0.1, 0.5, and 1% concentrations under petri dish conditions. Seven selected plant extracts were applied to rice seeds with soil drench application or seedling at 3-4 leaf stages with soil and foliar applications under greenhouse conditions. For comparison with extracts, we used urea at 0.6%. Of the 17 water extracts used in this study, 10 extracts reduced rice growth, but the other 7 extracts (P. guajava, A. vera, A. tuberosum, M. sativa, A. sativum, and G. max) increased growth by 40-60% on compared to the control in Petri dish bioassay. Thus, these 7 extracts were selected for further study. Under greenhouse conditions, rice growth also increased by 20-40% when the same 7 extracts were applied to rice seeds using soil drench application. Furthermore, at the 3-4 leaf stage rice growth also increased 30-80% or 30-60% when the same 7 extracts were applied using soil and foliar applications. Overall, the 7 extracts produced higher rates of growth promotion when soil drench application was used than when foliar application was used. In the case of boiling water and ethanol extracts, rice growth increased only 20% in response to both soil drench and foliar application of the same 7 extracts. Rice growth promotion was greater when extracts were produced using water extraction method than boiling water and ethanol extraction methods. Most notably, the 7 water extracts used in this study produced higher rates of growth promotion than urea at 0.6% which is typically used for crop growth promotion. Overall, the 7 water extracts when applied using soil drenching method can be used as effective growth promotors of rice in organic agriculture.

• The Plant Pathology Journal
• /
• v.31 no.3
• /
• pp.310-315
• /
• 2015

Certain bacterial species associate with plant roots in soil. The plant growth-promoting rhizobacteria (PGPR) stimulate plant growth and yield in greenhouse and field. Here, we examined whether application of known bacilli PGPR strains stimulated growth and asexual reproduction in the succulent plant Kalanchoe daigremontiana. Four PGPR strains B. amyloliquefaciens IN937a, B. cereus BS107, B. pumilus INR7, and B. subtilis GB03 were applied to young plantlets by soil-drenching, and plant growth and development was monitored for three months. Aerial growth was significantly stimulated in PGPR-inoculated plants, which was observed as increases in plant height, shoot weight, and stem width. The stimulated growth influenced plant development by increasing the total number of leaves per plant. Treatment with bacilli also increased the total root biomass compared with that of control plants, and led to a 2-fold increase in asexual reproduction and plantlet formation on the leaf. Collectively, our results firstly demonstrate that Bacillus spp. promote vegetative development of K. daigremontiana, and the enhanced growth stimulates asexual reproduction and plantlet formation.

• The Korean Journal of Pesticide Science
• /
• v.11 no.1
• /
• pp.27-31
• /
• 2007

Trifloxystrobin standard was analyzed by high performance liquid chromatography (HPLC). The recovery of the trifloxystrobin and it's metabolite CGA321113 were $84.6{\sim}95.3%$ and $86.4{\sim}87.3%$ and their detection limits for both of them were 0.04 mg $kg^{-1}$. In case of foliar application in the chinese cabbage (Brassica campestris L. ssp pekinnensis (Lour.) Rupr.), the amount of the residue of trifloxystrobin was above the maximum residue level (temporary MRL, 0.5 mg $kg^{-1}$) when it was treated either two times three to five days before harvest or three times three to seven days before harvest. Whereas in case of drenching the mount of the residue was below the temporary MRL, the residues in the cabbage in both the cases where the recommended amount (150 mL of the solution diluted 1500 times) and double of the amount were treated were 0.16 and 0.31 mg $kg^{-1}$, respectively. In conclusion, it should be safe to apply the trifloxystrobin (22% WP) in the soil of cabbage field abiding by the tentative recommendation level, but for the foliar application it appeared inappropriate.