• Korean Journal Plant Pathology
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• v.14 no.5
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• pp.484-490
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• 1998

Microorganisms associated with seed-rhizome rot of gingers preserved in three underground storage caves were identified with respect to rot types. Rot patterns were grouped into 4 different types : yellow soft rot, brown rot, localized ring rot, and water-soaked rot. Water-soaked rot was highest in frequency with 40% and ring rot the least with 14%. Causal pathogens differed with rot type, yellow soft rot by Erwinia carotovora and Pseudomonas aeruginosa, brown rot by Fusarium solani and Pseudomonas aeruginosa, localized ring rot by F. solani, and water-soaked rot by Pythium spinosum and P. ultimum. Pythium myriotylum, the causal pathogen of ginger rhizome rot which occurs severely in fields was rarely detected from storage seed-rhizomes suggesting its minor involvement with storage rot. Pathogenic Pythium isolates were frequently obtained from both rhizome surface and inner tissues of rotten rhizomes. Detection frequency of Pythium isolates in inner tissues decreased as increasing distance from rhizome surface. In wound-inoculation tests, above pathogens caused a varying degree of rot on healthy rhizomes at 15$^{\circ}C$, 2$0^{\circ}C$ and 3$0^{\circ}C$ with increasing severity at higher temperatures.

• Research in Plant Disease
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• v.10 no.2
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• pp.87-93
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• 2004

Rhizome rot of ginger, caused by Pythium myriotylum, a major limiting factor for its production, has occurred annually, but become severe, especially in hot and humid years with frequent rainfalls in Korea. Most studies on rhizome rot have been carried out since 1980s in the National Institute of Agricultural Sciences and Technology, Honam Crop Experimental Station and Choongnam Provincial Rural Development Administration. Many aspects of rhizome rot, such as survey of the disease incidence, taxonomy, pathogenicity and physiology of pathogen, and ecology of soilborne inocula have been studied in the researches. However, intensive studies have been concentrated on management technologies of the disease including seed-rhizome disinfection, soil sterilization, evaluation of cultivar resistance, and fungicide application, and most developed technologies have been used in commercial farmings. In future, development of resistant varieties and simple soil disinfection technologies applicable in Korean condition and economically feasible fungicide application technology have to be developed for better management.

• Korean Journal of Agricultural Science
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• v.26 no.1
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• pp.1-5
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• 1999

This experiment was carried out to define the development of control method against rhizome rot of ginger. It was difficult to control of rhizome rot of ginger completely by way of only rhizome sterlization. When soil were stenilized with dazomet, and metalacxyl granule was applied, higher than 95% of control value as well as 39% of yield increase compared to control were found. Soil drenching with metalacxyl cupper oxychloride and streptomycin controlled the rhizome rot satisfactorily, but was inferior to the above mentioned combination.

• The Plant Pathology Journal
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• v.34 no.3
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• pp.218-235
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• 2018

Plant growth promoting rhizobacteria and endophytic bacteria were isolated from different varieties of turmeric (Curcuma longa L.) from South India. Totally 50 strains representing, 30 PGPR and 20 endophytic bacteria were identified based on biochemical assays and 16S rDNA sequence analysis. The isolates were screened for antagonistic activity against Pythium aphanidermatum (Edson) Fitzp., and Rhizoctonia solani Kuhn., causing rhizome rot and leaf blight diseases in turmeric, by dual culture and liquid culture assays. Results revealed that only five isolates of PGPR and four endophytic bacteria showed more than 70% suppression of test pathogens in both assays. The SEM studies of interaction zone showed significant ultrastructural changes of the hyphae like shriveling, breakage and desication of the pathogens by PGPR B. cereus (RBacDOB-S24) and endophyte P. aeruginosa (BacDOB-E19). Selected isolates showed multiple Plant growth promoting traits. The rhizome bacterization followed by soil application of B. cereus (RBacDOB-S24) showed lowest Percent Disease Incidence (PDI) of rhizome rot and leaf blight, 16.4% and 15.5% respectively. Similarly, P. aeruginosa (BacDOB-E19) recorded PDI of rhizome rot (17.5%) and leaf blight (17.7%). The treatment of these promising isolates exhibited significant increase in plant height and fresh rhizome yield/plant in comparison with untreated control under greenhouse condition. Thereby, these isolates can be exploited as a potential biocontrol agent for suppressing rhizome rot and leaf blight diseases in turmeric.

• Korean Journal of Medicinal Crop Science
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• v.19 no.4
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• pp.246-250
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• 2011

This study was carried out to investigate the characteristics of Rhizome rot incidence of Platycodon grandiflorus by cultivation period and ridge width and furrow depth. The three types of ridge width 0.8, 1.0, and 1.2 m and several levels of furrow depth and 6 levels cultivation period. This experiment was done in farmer's farm and the treatments were also classified in the same spot. In this investigation, ridge width, soil water content, soil hardness, and cultivation period were positively related with Rhizome rot incidence, however, furrow depth was negatively related with that. So this experiment could draw a conclusion : excess water damage and soil hardness could directly or indirectly effect on the Rhizome rot incidence, so cultivation method should be developed such as making underground ditch or cultivation in well draining soil for escaping excess waster damage.

• The Plant Pathology Journal
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• v.26 no.2
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• pp.198-202
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• 2010

A study was conducted to find out the relationship of physico-chemical properties (viz. organic carbon(OC), pH, electrical conductivity, nitrogen, phosphorus and potassium content) of ginger growing soil with incidence percentage of rhizome rot and wilt disease complex of ginger. Organic carbon content and pH of the ginger soil contributed significantly (93%) in the prediction of ginger rhizome rot and wilt disease complex incidence with negative correlation. Soil having weak acidic reaction with OC percent greater than 2.25 was observed to have the lower average incidence of the disease.

• Plant Resources
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• v.2 no.2
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• pp.81-87
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• 1999

Sixteen isolates showing relatively strong antagonicity against the ginger rhizome rot pathogen, Pythium zingiberum, were selected among the 155 isolates from ginger rhizome surfaces and rhizospheres of ginger cultivation fields in Wanju, Chonbuk. The isolate, 'HB 26-5'showing the strongest antagonicity was finally selected by testing duration of inhibition effect and pathogenicity to ginger. The isolated antagonistic microorganism, 'HB 26-5' was rod shape, gram positive and formed endospore. The isolate produced acids utilizing glucose, arabinose, xylose and mannitol, and acetoin at VP test, and grew anaerobically. Temperature range for growth was from 10 to 4$0^{\circ}C$ . Reaction to catalase and gelatin, hydrolysis were positive, and casein hydrolysis and indol production were negative. Based on the mycological characters and the fatty acid composition, it was identified as Bacillus polymyxa. The pathogenicity test of isolated Bacillus polymyxa 'HB 26-5'on 22 crop cultivars resulted that only the lettuce was influenced in germination, and the others were not affected.

• Korean Journal of Microbiology
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• v.18 no.4
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• pp.172-179
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• 1980

The rhizome rot of ginger, caused by fusarium oxysporum f.zingiberi, gives a great deal of damages to the ginger farming in Korea. Main symptoms to the disease include the yellowing and blighting of the stems as the rotting of rhizomes. The infection rate was 20 percent in Bongdong, Jeonbug, whereas 10 percent in Susan, Chungnam. The rate was higher at the farm where gingers had been cultivated for many years. To control the disease, soil fungicides Dowfum MC-2 and Tolene C-17 were turned out to be more effective than Di-Trapex nad Daconil. Treatment of Benlate to the rhizome pieces, which were cut for propagation, also showed a better result as compared with that of Othocide. Dual treatment of both Dowfum MC-2 or Tolene C-17 to the farm soil and Benlate to the rhizome pieces was recommended for the best chemical control.

• Korean Journal Plant Pathology
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• v.14 no.3
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• pp.253-259
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• 1998

Effects of soil disinfection, fungicide application, and narrow ridge cultivation on ginger rhizome rot development were examined in two naturally-infested fields at Seosan, Choongnam province. Soil disinfection treatments were assigned to main plots, and fungicide and ridge treatments to sub-plots in a split plot design with three replications. The rhizome rot started in late July, and progressed rapidly until late September with the peak incidence in mid-august to early September. Soil disinfection by dazomet application showed the most prominent inhibition effects in both fields, where the disease was reduced by the treatment from 17.5% to 4.8% in one field, and from 51.0% to 2.2% in the other field. Three to five applications of fungicide metalaxyl-copper during the growing season inhibited the disease by 89.7% in one field, but less effectively in the other field. Narrow ridge cultivation reduced the disease effectively by 78.1% and 63.9%, compared to the unridged control plots in each field, respectively. Germination rate of seed-rhizomes and growth of ginger plants were similar between treatments, except when the plots received improper aeration after applying dazomet, and then the germination rate was significantly reduced. The greatest yields were obtained in the disinfected plots, regardless of rhizome rot incidence, except one control plot with very little disease. Ginger yield was negatively correlated with disease severity. However, the yield of ridge plots averaged 58∼59% compared to those of the unridged plots, due mainly to the half planting rate of the ridge plots. In spatial progress, the disease in the disinfected plots started from a single focus of the inoculum, and spread into the adjacent areas only, whereas in the untreated plots, the disease started from many foci that were distributed over the plot, and rapidly progressed to make an epidemic during the season. The soil density of P. myriotylum in the disinfected plots was not changed or, if not, increased slightly during the season. However, in the untreated plots it increased rapidly to reach the density 3 to 5 times greater by the end of the season.

• Korean Journal of Environmental Agriculture
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• v.17 no.1
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• pp.1-4
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• 1998

The ecology of rhizome rot incidence rates between Seosan, Chungnam and Bongdong, Chonbuk province were surveyed in this experiment. The rhizome rot incidence rate of Seosan was lower than that of Bongdong. The average ginger product of former province was 1,140kg, whereas it's 818kg per 10a. in latter province. Treatment after disease incidence frequently used fungicide at Seosan. There were different soil physiological property between fields. Although Eunhari and Yulsori were belong to Bongdong province, incidence rate was low at Eunhari, contained 23% clay and high incidence rate at Yulsori, approximately contained 60% silt. Many soil chemical properties of cultivated area were belong to optimum concentration range, but phosphate(P) was higher than optimum concentration, 450-550ppm. The number of soil fungi in the middle of cultivated season tended to show the highest. Both bacteria and actinomyces` number was similar to the result of fungi. The bacteria/fungi ratio was greatly different between surveyed fields.