We have performed an experiment to evaluate the efficacy of salt and hot water treatments in soil for managing situations where high-risk plant-parasitic nematodes (PPNs) are detected in farms and flower shops that cultivate foliage plants. The density of Pratylenchus penetrans was reduced by 100% with salt treatments of 20 and 40 kg m-2, while decreases of 95% and 99.8% were observed with treatments of 5 and 10 kg m-2, respectively. In the hot water treatment, Pratylenchus penetrans decreased by 97.6% compared to the initial density. The salt treatment resulted in a decrease in pH and an increase in electrical conductivity (EC) compared to untreated soil. However, other characteristics, including organic matter content, available phosphorus, total nitrogen (T-N) rate, and exchangeable cations, did not differ from the control. In the case of hot water treatment, all properties were similar to those in the untreated group. As a result of this study, salt applications of more than 20 kg m-2 and hot water at 96°C could serve as effective control methods when high-risk PPNs are detected in flower shops and greenhouses located in urban or near-urban areas.

Current investigations provide a comprehensive understanding of the occurrence and biodiversity of plant-parasitic nematodes (PPNs) in the major citrusproducing regions of Jeju Island, South Korea. Our survey identified five genera and five species of PPNs from 82 infested Citrus unshiu field samples collected across 116 sites in the Jeju provinces. Community analysis revealed the highest prevalence of PPNs (39.02%) at Namwon-eup, significantly driven by Tylenchulus semipenetrans, followed by Paratylenchus sp., Helicotylenchus sp., Meloidogyne sp., and Pratylenchus sp. Data indicate that all 82 sites were infested with T. semipenetrans (70.68%), marking a considerable increase in prevalence compared to previous surveys and posing a significant threat to citrus cultivation. The study results also demonstrate the influence of soil type on PPNs communities, revealing correlations between soil texture and nematode diversity. Citrus orchards cultivated in black clay loam soil exhibited significant PPN infestations. Overall, the PPN survey underscores the economic importance of monitoring citrus nematode infection rates and maintaining economic threshold levels in citrus production. It also emphasizes the need for developing effective management strategies to control PPNs, which are essential for maintaining crop yield and ensuring agricultural sustainability.

Soybean (Glycine max L.) is one of the most important food crops in Korea and a crucial source of protein. However, soybean production is significantly impacted by various plant pathogens, including insect pests, plant-parasitic fungi, bacteria, and nematodes. The soybean cyst nematode (SCN), Heterodera glycines, is a major plant-parasitic nematode that causes an estimated annual loss of US$29 million in Korean soybean industry. Cultivating SCN-resistant soybean cultivars is considered the most effective method for managing this nematode. To identify such cultivars, we conducted resistance screening tests for 32 soybean cultivars. No resistant cultivar was found. Daewang cultivar exhibited moderate resistance to SCN, while the other 31 were susceptible. These findings suggest that Daewang is currently the best choice for fields infested with SCN. There is a critical need for developing SCN-resistant soybean cultivars in Korea.

Clover cyst nematode (Heterodera trifolii, CCN) is one of the important plantparasitic nematodes in the Republic of Korea, causing serious damage to Kimchi-cabbage in Gangwon province since 2017. Soil fumigants are the preferred choice for managing CCN. However, cabbage fields in Gangwon province have a slope, making it challenging to apply soil fumigants and use plastic mulch. Consequently, alternative materials should be developed for managing CCN. Nematicidal cover crops and resistant cultivars are among the alternatives. We conducted resistance screening of 82 white mustard (Sinapis alba) resources from a genebank at RDA against CCN for use as nematicidal cover crops or breeding materials. In the first assay (1st, 2nd, and 3rd pot experiments), 15 white mustard resources were selected, while others were susceptible to CCN. To confirm the reproducibility of resistance to CCN for 13 selected resources, the second assay was performed. As a result, five white mustard resource (IT297309, IT297312, IT302951, IT302953, IT302954) demonstrated resistance to CCN. These findings indicate the potential use of these five white mustard resources as nematicidal cover crops or for breeding cultivars of Kimchi-cabbage in Republic of Korea.

Southern root-knot nematode (SRKN, Meloidogyne incognita) is known to be responsible for annual economic losses of 38.2 million USD in cucumber cultivation in Korea. Nematicides are frequently used to manage SRKN in plastic greenhouses. A field experiment was conducted to assess the effect of a soil fumigant (dimethyl disulfide, DMDS) and a non-fumigant (fluopyram, FL) against SRKN during the winter fallow season in a greenhouse from October to December. Nematicidal efficacy was assessed at 43 days after treatment, and the root gall index was measured 4 months after transplanting cucumber seedlings. DMDS effectively reduced second-stage SRKN juvenile density with 91% control efficacy, while FL showed no control efficacy against SRKN. Root gall index values were significantly different (p=0.020) in DMDS treatment and controls at 1.0±0.00 and 4.3±0.58, respectively. This study showed that DMDS could be considered an effective nematicide for controlling SRKN in the fallow period in winter.

Membrane bioreactors (MBRs) employ a process of biological treatment that is based on a membrane that has the advantages of producing high-quality treated water and possessing a compact footprint. However, despite these advantages, the occurrence of “fouling” during the operation of these reactors causes the difficulty of maintenance.Hence, in this study, three physical cleaning methods, namely, backwashing, air scrubbing, and mechanical cleaning ball was performed to identify optimum operating conditions through laboratory scale experiments, and apply them in a pilot plant. Further, the existing MBR process was compared with these methods, and the field applicability of a combination of these physical cleaning methods was investigated.Consequently, MCB, direct control of cake fouling on the membrane surface was found to be the most effective. Moreover, as a result of operating with combination of the physical cleaning process in a pilot plant, the TMP increasing rate was found to be – 0.00007 MPa/day, which was 185% higher than that obtained using the existing MBR process. Therefore, assuming fouling only by cake filtration, about one year of operation without chemical cleaning is considered to be feasible through the optimization of the physical cleaning methods.