• The Korean Journal of Pesticide Science
• /
• v.6 no.4
• /
• pp.287-292
• /
• 2002

To establish effective and safe control method against Phytophthora root rot caused by Phytophthora capsici on tomato in hydroponic culture, three pesticides, oxadixyl copper hydroxide 8% WP, metalaxyl copper oxychloride 15% WP, and dimethomorph. dithianon 38% WP at 4 concentration levels were tested on potato dextrose agar medium inoculated with Phytophthora capsici. All pesticides inhibited mycelial growth, but two pesticides of them, metalaxyl copper oxychloride WP and dimethomorph. dithianon WP, were selected as effective pesticides for the efficacy test in a hydroponic culture. Forty days after transplanting of tomato seedlings, 4 ml of sporangia of P. capsici (about 25 sporangi/ml) per plot was inoculated around tomato plant root, and then 5 days after inoculation, the pesticides diluted at 5,000 times were drenched 1, 2 or 3 times per plot on the culture cube at 15 days interval. Fifteen days after drenching, tomato fruits and hydroponic culture solution were sampled for the analysis of pesticide residues. Dimethomorph was detected 0.001 and 0.003 mg/kg in tomato of the plots sprayed 2 and 3 times with dimethomorph dithianon WP of which detection levels were far below compared with 1.0 mg/kg of the Korean MRL of dimethomorph on tomato. Incidences of Phytophthora root rot were $30.5{\sim}50%$ in the plots drenched at 1 or 2 times with metalaxyl.copper oxychloride WP, and $16.7{\sim}25%$ in the plots treated with dimethomorph dithianon WP. However, there was no incidence of Phytophthora root rot in the plots treated at 3 times with both of pesticides, showing no phytotoxic effect. Based on the results, the drenching of these pesticides on the culture cube could be recommended as a very safe and effective control method for Phytophthora root rot in tomato.

• Research in Plant Disease
• /
• v.18 no.2
• /
• pp.117-122
• /
• 2012

In 2006, the effect of soil pH adjustment on control of common scab of potato caused by Streptomyces spp. was evaluated in the field. Soil with an original pH 5.7 was treated with sulfur of 42 kg/10a and calcium hydroxide of 81.6 kg/10a and 184.5 kg/10a to adjust pH 5.0, 6.0 and 6.5, respectively. Additionally, the effect of gypsum (522 kg/10a) on soil pH and disease severity was examined. The soil pH of sulfur treatment plot was continuously declined from 5.13 at tuber initiation time to 5.01 at harvest. The disease severity of sulfur treatment plot was relatively low (22.8%) and the marketable yield of that was high (90.5%). By contrast, the soil pHs treated with calcium hydroxide (81.6 kg/10a and 184.5 kg/10a) were increased (pH 6.06 and 6.49, respectively) at harvest. In addition, calcium hydroxide treatment plots showed higher disease severities (51.0% and 61.1%), and lower marketable yields (55.7% and 37.0%). Meanwhile, the soil pH of gypsum treatment plot was not changed until harvest, and the disease severity and the marketable yield were not significantly different from those of control. The effect of crop rotation was also evaluated with four crops such as welsh onion, soybean, corn and Chinese cabbage. These crops were planted in the infested field from 2005 to 2007, and potatoes were planted in the same field in 2008. The disease severities of potatoes produced after rotations with welsh onion, soybean, corn and Chinese cabbage for 3 years were 13.1%, 16.7%, 28.9% and 30.2%, respectively. However, the disease severity of 73.1% was shown in continuous cropping of potato for 3 years. In addition, similar effects were exhibited in the marketable yield. These results demonstrate that the adjustment of soil pH and crop rotation might be very useful tools to control common scab of potato.

• Korean journal of applied entomology
• /
• v.47 no.3
• /
• pp.273-286
• /
• 2008

Road-map for the environmental friendly integrated pest management(IPM) of insect pests was drawn up on the strawberry vinyl-houses of farmer's field. Major insect pests were occurred Tetranychus urticae and Aphis gossypii during the strawberry plant seeding in the vinyl house and open field. Also, same insect pests were occurred in the vinyl house during harvesting season of strawberry. For the control of T. urticae and A. gossypii, Phytoseiulus persimilis and Aphidius colemani as natural enemies were input to the vinyl house, respectively. However, because these natural enemies could not control insect pest populations, acaricide and insecticide were sprayed. Then natural enemies were input again in the vinyl house. Natural enemies could not endure the intense cold and differences of temperature and relative humidity between day and night during strawberry harvesting season. So, their behavior and control activity of pests were more decrease than pests. Firstly, natural enemies are input in the vinyl house during the early breeding season of strawberry, secondly, acaricides and insecticide are sprayed for the control of mites and aphids, respectively, during the middle breeding season in the hard winter. Finally, natural enemies are re-input in the vinyl house during the middle and late breeding season.

• Korean Journal of Environmental Agriculture
• /
• v.9 no.1
• /
• pp.47-52
• /
• 1990

Metaldehyde Granule (6%) was sprayed 7, 15 and 30 days before harvest at the level of 0.3kg AI/l0a to evaluate metaldehyde residues on the inner and outer part of chinese cabbage. Roots of chinese cabbage were also analyzed. Results were as follows : 1. The amount of free acetaldehyde in chinese cabbage was 0.02-0.18ppm. 2. It was shown that metaldehyde residues in the leaf and root of chinese cabbage increased as the number of treatment increased and treatment period decreased. 3. The metaldehyde residue range in the leaf was in the range of 0.11-1.4ppm 4. The difference of metaldehyde residue on the inner and outer part of chinese cabbage was in the range of 0.01-0.6ppm and the residue on inner parts was slightly higher than outer part. 5. The metaldehyde residue in the root was in the range of 0.04-0.63ppm.

• Journal of Bio-Environment Control
• /
• v.19 no.4
• /
• pp.311-316
• /
• 2010

This study was conducted to investigate the effect of anaerobic fermentation of wheat bran to prevent root-knot nematodes which are infected in plastic house due to over 10 years continuous cultivation of fruits and vegetables. Anaerobic fermentation treatment of wheat bran was done for 20 days by mixture of 2,000 kg fresh wheat bran per 10 are and soil with water in 30 cm soil depth. Chemical treatment of fosthiazate was done by mixture of 6 kg soil for 7 days. Both treatments show suppression of density of rootknot nematodes, especially in anaerobic fermentation treatment. Anaerobic fermentation treatment keeps the low level of root-knot nematode density until 90 days of cultivation and also showed good effect of melon growth. Related with death percentage of melon plant, anaerobic fermentation treatment shows only 3% and also large size of quality fruit but control 65%. Anaerobic fermentation treatment of wheat bran have proved to control the level of root-knot nematodes instead of synthetic chemicals for at least one cropping season and it showed good effect to fruit quality.

• Korean journal of applied entomology
• /
• v.22 no.4 s.57
• /
• pp.244-250
• /
• 1983

This study was carried out to analyst the damage due to the brown planthopper, Nilapalvata lugens Stal, at different stages(maximum tillering, booting, heading, and milking) of rice. The results are as follows: The population density of the migrating and the first generations of the brown planthoppers seemed not to be large enough to cause significant effects on the plant height and the number of tillers, while the second and the third generations caused significant reduction in 1000 grain weight(Yl) and the filled grain percentage$(Y_2)$. They were very closely related to the population density(X) of tile second generation of the BPH; $$Y1(g)=25.602-0.0213X(r=-0.5205^{**})$$ $$Y2(\%)=76.97-0.1370X(r=-0.4820^{**})$$ The relationship between rice yield (Yg) and the accumulated total density (X) of BPH per hill by the time of harvest; $$Y(g)=24.694-0.0576X(r=-0.6959^{**})$$ Since the source of the outbreak BPH is the first generation, it nay conclude that the detailed information on the population status of the first generation; density, age components, ratio of the brachypterous form, are very important in relation to management of the pest.

• Horticultural Science & Technology
• /
• v.28 no.5
• /
• pp.762-767
• /
• 2010

This study was conducted to investigate the influence of formulation of fungicides on epicuticular waxes in 'Campbell Early' grapes. Non-bagged and bagged berries were treated with wettable powder, suspension concentrate and emulsifiable concentrate 15 days after full bloom (DAFB) and 48 DAFB (veraison), respectively. Fruit skin was observed by naked eye and scanning electron microscope (SEM) at harvest. Remarkable white blots were observed on the berries treated 48 DAFB in the order of wettable powder, suspension concentrate, and emulsifiable concentrate. The observation by SEM showed all formulations of fungicides damaged the ultra-structure of epicuticular waxes; also, an unknown substance was observed on treatment with wettable powder and suspension concentrate. Moreover epicuticular wax appeared to be melting on the grapes treated with emulsifiable concentrate. Also, non-bagged grapes showed serious contamination of epicuticular wax by some unknown substance, but bagged grapes had only fungicides' traces.

• Korean Journal Plant Pathology
• /
• v.2 no.3
• /
• pp.193-198
• /
• 1986

Bottom rot of Chinese cabbage (Brassica pekinensis Rupr) hitherto undescribed in Korea is caused by Rhizoctonia solani Kuhn. Development of bottom rot in fall crops was observed and the efficiencies of fungiciial control in naturally infested field in Southern region were studied. Bottom rot symptom started to develop 20 days after transplanting 20 day old seedlings, which corresponded to the middle growing stage. At the reading stage, the infection rate increased substantially, which progressed upto an average of $52\%$ at harvesting time. The overall infection rate was about $30\%$ in Chinese cabbage field under plastic film house cultivation. However, disease intensity of fall crops was less severe than that of crops in plastic film house. where plants infested earlier, stunted and their growth was extremely poor. Optimum temperature for mycelial growth of bottom rot isolates of R. solani was $20\~25^{\circ}C$ on potato-sucrose agar. This fungus was highly pathogenic on seedlings of Chinese cabbage, radish, sesame and rape resulting in high percentage of damping-off. For other crops, such as lettuce, tomato the cucumber, the germination was delayed for 2-3 days and the percentage damping-off was lower. Anastomosis group of this fungus was idenlfied as AG II-I. Soil drenching of fungicide pencycr WP., three applications at 10 day interval, was effective; indicating the most promising one with control value $80\%$.

• Applied Biological Chemistry
• /
• v.50 no.1
• /
• pp.23-28
• /
• 2007

Auxin-producing antagonistic bacterium K11, which can inhibit Phytophtora capsici, was isolated from a local red-pepper field soil in Gyeong-buk. In order to check for additional PGPR(plant growth promoting rhizobacterium) functions of the strain K11, we confirmed siderophore and cellulase productions by CAS (chrome azurol S) blue agar and CMC plate with congo red, respectively. The strain K11 was identified as Bacillus licheniformis with 98% similarity on 16s rDNA comparison and Biolog analyses. B. licheniformis K11 promoted mung bean adventitious root induction and enhanced root growth of mung bean (160%), pea (150%), and Chinese cabbage (130%), Also, B. licheniformis K11 was able to effectively suppress (63%) P. capsici causing red-pepper blight in the pot in vivo test. Therefore, we could select a triple-functional PGPR which has auxin, siderophore, and cellulase producing ability for effective crops production in organic farming.

• Journal of Mushroom
• /
• v.21 no.3
• /
• pp.140-144
• /
• 2023

The objective of this study was to achieve biological control of green mold disease in Pyogo mushrooms using antagonistic microorganisms. Bacillus subtilis BSM320 cells inhibited mycelial growth by 48-60% against three Trichodermaisolates including T. hazianumisolated from the substrates of Lentinula edodes, showing their antifungal activity.The bacteria were cultured to a high density of 4.2 × 10⁹±113.7 cfu/mlin aqueous extract of composted spent mushroom substrates of L. edodes containing 1% glucose and showed a higher growth rate than that observed when using the commercial medium, Luria-Bertani broth. The bacterial culture showed a 75% protective effect without damaging the mushroom fruiting bodies. These results suggest that B. subtilis BSM320culture is suitable for biological control of green mold disease during mushroom cultivation.