Search Results (36)

Since the use of methyl bromide has been prohibited globally because of environmental concerns, several alternative fumigants have been newly developed and applied to fresh products. However, single treatment with a methyl bromide alternative fumigant cannot completely replace methyl bromide treatment for some products because of issues associated with long treatment times and phytotoxicity. In this study, we compared the mortality of two agricultural pests, Tetranuchus urticae and Planococcus citri, after single treatment with methyl bromide and combined application of methyl bromide and cold treatment to confirm the synergistic effects of chemical and physical treatments. The combined application of methyl bromide and cold treatment was effective against the nymph and adult stages of T. urticae, but no synergism was observed at the egg stage. For P. citri, the required dosage of methyl bromide decreased when methyl bromide treatment was followed by low temperature, possibly because of the susceptibility of P. citri to cold treatment. These results indicate that the synergism of fumigants with cold treatment can differ by pest species and growth stage, and further studies on other pests are needed to reduce methyl bromide usage. Full article

Polyphenols are organic molecules extracted from various fruits, such as coffee and citrus, that possess biological activity and antioxidant properties. However, the presence of polyphenols in the environment is hazardous to water quality and living health. Among a variety of water remediation methods, adsorption remains a staple in the field. Therefore, this work aims to develop porous polycaprolactone: poly(methyl methacrylate) (PCL:PMMA) membranes as a support for hydrotalcite immobilization for the removal of chlorogenic acid polyphenol (CGA) from aqueous solutions. Due to the hydrophilic nature of hydrotalcite, the adsorbent was functionalized with hexadecyltrimethylammonium bromide (CTAB) to increase its affinity for CGA, resulting in a removal efficiency of approximately 96%. Composite fiber membranes were prepared by solution-blowing spinning with specific amounts of hydrotalcite added (i.e., 1 to 60 wt%). A 3:1 PCL:PMMA blend resulted in superior mechanical traction (0.8 MPa) and stress deformation (70%) compared to pure PCL (0.7 MPa and 37%) and PMMA (0.1 MPa and 5%) fibers. PCL:PMMA membranes with 60% LDH-CTAB exhibited CGA removal rates equal to 55% in the first cycle while maintaining the capacity to remove 30% of the polyphenol after five consecutive reuses. Removal rates up to 90% could also be achieved with an appropriate adsorbent dose (2 g L⁻¹). Adsorption was found to follow pseudo-second-order kinetics and was adequately described by the Langmuir model, saturating LDH-CTAB active sites in four hours. PCL:PMMA:LDH-CTAB composites can be considered a potential alternative to support adsorbents for water remediation. Full article

Pests in wood pellets are treated using methyl bromide (MB) fumigation, which has low efficacy against pests because of its high adsorption to wood pellets. In this study, we assessed the feasibility of combined MB and phosphine (PH₃) fumigation of adults and pupae of Tribolium castaneum and Sitophilus zeamais. The LC₉₉ of MB for T. castaneum pupae were 31.49, 39.21, and 53.48 mg/L for 24 h treatment at 20, 10, and 5 °C, respectively. For S. zeamais, the LC₉₉ were 24.32, 36.06, and 51.49 mg/L under the same conditions. The addition of PH₃ (0.04 mg/L) to MB against T. castaneum pupae significantly decreased the LC₉₉ of MB to 4.05 mg/L at 20 °C. MB was strongly adsorbed to wood pellets, which prevented complete extermination of T. castaneum at loading ratios between 20 and 60%. However, at the highest filling ratio (60%), the addition of 0.7 mg/L PH₃ with 70 mg/L MB achieved 100% mortality for T. castaneum. When pupae of S. zeamais were targeted, MB + PH₃ effectively disinfected both stages of both pests after 24 h at 5, 15, and 20 °C. Combined MB + PH₃ treatment is an alternative to the currently approved MB treatment for controlling exotic beetles in imported wood pellets in Korea. Full article

Management of stored-product pests has historically relied on fumigation when pest populations become large. However, the ban of the fumigant methyl bromide and the ineffectiveness of other pesticides stress the need for alternative fumigants. Therefore, laboratory studies were conducted to evaluate the efficacy of ethanedinitrile (EDN) against different life stages of the mite Tyrophagus putrescentiae and to determine the sorption and desorption of EDN by dry-cured ham meat. The results showed that eggs were the most tolerant life stage to EDN fumigation, with an estimated LC₅₀ of 0.6 mg/L. Tyrophagus putrescentiae mixed life-stage colonies were controlled at 1.3 mg/L, and less than 0.05% of the population survived following treatment with 0.6 mg/L within 24 h at 25 °C. The free-headspace concentrations of EDN in fumigation chambers containing ham decreased by 97% of the initial concentrations applied (2.6 and 4.8 mg/L) after the 24 h fumigation period. The EDN sorption in ham followed the first-order kinetics, with half-life values of 5.0 and 4.9 h for 2.6 and 4.8 mg/L, respectively. The percentage losses of EDN per hour were calculated to be 12.8 and 13.2% at 2.6 and 4.8 mg/L, respectively. Our study indicates that EDN controls T. putrescentiae in the laboratory. Full article

In recent years, noticeable progress has been made in the development of alternative extraction systems characterized by greater sustainability. In this context, deep eutectic solvents (DESs) have emerged as a promising alternative to the conventional solvents commonly used in metal extraction. This work focuses on investigating the extraction of lanthanum in an aqueous solution of sulfuric acid using a deep eutectic solvent, employing molecular dynamics simulations (MD). The structural characteristics of the solvent and its interactions with the components of the aqueous solution are explored. In this study, tetraethylammonium bromide (TEABr) is combined with ethylene glycol (EG) to form a DES, in which sodium cyanide (NaCN) is subsequently solubilized. According to the results obtained from the MD simulation, the primary interactions in the DESs are established through hydrogen bonds between the bromine and the hydrogens of the methyl group of tetraethylammonium at 3.5 Å, as well as between the bromine and the hydrogens of the methylene group of ethylene glycol at 3.5 Å. Similarly, the main interactions between the binary DES and sodium cyanide occur through the hydrogens of the hydroxyl group of EG and the carbon of cyanide at 1.7 Å, and between the oxygen of the hydroxyl group of EG and the sodium at 2.5 Å. In the acidic solution, the primary interaction is highlighted between the lanthanum ion and the oxygen of the bisulfate at 2.8 Å. Additionally, it is observed that the interaction between the DES and the aqueous solution occurs between the lanthanum and the oxygen of the hydroxyl group of EG, as well as between the lanthanum and the carbon of cyanide at 4.4 Å. It is important to note that, when increasing the temperature from 25 to 80 °C, the interaction distance between the lanthanum and the carbon of cyanide decreases to 2.4 Å, suggesting a possible correlation with the increase in lanthanum extraction, as experimentally observed. Overall, this study underscores the importance of considering the fundamental structural interactions of the DES with the lanthanum acid solution, providing an essential theoretical basis for future experimental investigations. Full article

High-risk termites in wood imported to the Republic of Korea are currently treated with methyl bromide (MB), which has ozone-depleting properties and is highly toxic. This study evaluated the effectiveness of sulfuryl fluoride (SF) as a quarantine treatment against Reticulitermes speratus Kolbe (Blattodea: Rhinotermitidae) in wood, along with its wood sorption and penetration capacity. The LCt₅₀ and LCt₉₉ values for SF were 30.87 and 42.53 mg h/L at 23 °C and 151.62 and 401.9 mg h/L at 5 °C, respectively. The SF Ct values did not significantly differ between dry and wet wood at loading ratios of 10%, 30%, and 50% at both 5 °C and 23 °C (p > 0.05). In a closed wooden cube, the LCt₅₀ and LCt₉₉ for SF for R. speratus were 31.59 and 53.34 mg h/L, respectively, indicating an excellent wood penetration ability. SF caused 100% termite mortality with a 90% loading ratio in the scale-up trials (500 L). The SF concentration during ventilation decreased below the threshold limit value (TLV) of 5 ppm within 30 min, confirming that the working conditions were safe. This study provides a basis for the use of SF as an alternative to MB for the treatment of termites in wood. Full article

Pineapple mealybug, Dysmicoccus brevipes (Hemiptera: Pseudococcidae), is a significant pest in pineapple production and a key trade barrier. We explored the potential use of ethyl formate (EF) as a methyl bromide alternative for the postharvest fumigation of D. brevipes in imported pineapples. When treated at 8 °C for 4 h, EF fumigation was effective against D. brevipes with LCt_99, the lethal concentration × time product of EF necessary to achieve 99% mortality of D. brevipes nymphs and adults at 64.2 and 134.8 g h/m³, respectively. Sorption trials conducted with 70 g/m³ EF for 4 h at 8 °C using 7.5, 15 and 30% pineapple loading ratios (w/v) indicated that loading ratio lower than 30% is necessary to achieve the LCt₉₉ values required to control D. brevipes. In a scaled up trial using 1 m³ chamber, EF fumigation with 70 g/m³ for 4 h at 8 °C with 20% pineapple loading ratio (w/v) resulted in a complete control of D. brevipes treated. There were no significant differences in hue values, sugar contents, firmness, and weight loss between EF-treated and untreated pineapples. Our results suggest that EF is a promising alternative to methyl bromide fumigation for the postharvest phytosanitary disinfection of D. brevipes in pineapples. Full article

With an increase in the international trade of agricultural and non-agricultural products, there is an increase in the possibility of introducing hitchhiking insect pests such as Halyomorpha halys, which has been detected on imported vehicles and agricultural machinery. Although methyl bromide (MB) is provisionally used to control invasive pests, it is classified as a restricted chemical owing to its potential to deplete the ozone layer and pose health risks to humans in cases of inadequate ventilation, as well as concerns regarding consumer safety. Therefore, this study investigated ethyl formate’s (EF’s) efficacy against H. halys and its efficacy and sorption, as an alternative to MB, on main electronic components, including alternators, ignition coils, and motors. Fumigation with 35 and 70 g/m³ EF for 4 h at 15 °C had no damage on the main electronic components as evaluated using various operation tests. In a commercial trial, H. halys infestation was effectively controlled with 35 g/m³ EF fumigated for 4 h at 23 °C using a 30 m³ polyvinyl chloride tarpaulin fumigation chamber. After ventilation, the EF concentration decreased below the safety level within 10 min and reached the zero level within 40 min for worker safety. This novel sanitary treatment using EF fumigation on imported agricultural machinery could be an effective method without causing mechanical damage. Full article

The storage mite Tyrophagus putrescentiae infests a wide range of food products including pet food. Control of this mite depends on chemical methods such as fumigation and spraying with insecticides. Methyl bromide was used as a fumigant for high-value stored products, especially to control mite infestation in dry-cured hams and cheeses, but it is now banned for most uses in many countries because of its atmospheric ozone-depleting effects. Effective alternatives to methyl bromide are needed to develop integrated pest management programs for this pest. Liquid smoke is a naturally derived flavoring and preservative with known antimicrobial properties. The objective of this study was to investigate the efficacy of liquid smoke preparations, with varying phenol and carbonyl concentrations and pH, on the survivability and orientation behavior of T. putrescentiae in a model semi-moist pet food. The mite survivability assays using liquid smoke-treated and untreated semi-moist pet food samples indicated that there was no difference among treatments (p > 0.05) for mite infestation and survival. Two-choice behavioral assays using semi-moist pet food cubes dipped in varying concentrations (0%, 0.3%, 1%, 5%, 10%, 25%, 50%, or 100% v/v) of liquid smoke preparations found that some of the liquid smoke preparations containing medium to high carbonyl content repelled the mites. In conclusion, liquid smoke did not kill or inhibit the mite population growth in semi-moist pet food. However, some liquid smoke fractions containing medium to high carbonyl content were repellent to mites and may retard mite infestation in stored semi-moist foods. Full article

Paracoccus marginatus is a highly polyphagous invasive pest that poses a significant quarantine threat to tropical and subtropical countries. Infested commodities in international trade should undergo phytosanitary treatment, and irradiation is recommended as a viable alternative to replace methyl bromide fumigation. Dose-response tests were conducted on the 2-, 4-, and 6-day-old eggs and gravid females of P. marginatus using the X-ray radiation doses of 15–105 Gy with an interval of 15 Gy. Radiotolerance was compared using ANOVA, fiducial overlapping and lethal dose ratio (LDR) test, resulting in no significant difference among treatments, except for the overall mortality and LDR at LD₉₀ (a dose causing 90% mortality at 95% confidence level). The estimated dose for LD_99.9968 was 176.5–185.2 Gy, which was validated in the confirmatory tests. No nymphs emerged from a total of 60,386 gravid females exposed to a gamma radiation dose range of 146.8–185.0 Gy in the confirmatory tests. The largest dose in confirmatory tests should be the minimum threshold for phytosanitary treatment, consequently, a minimum dose of 185 Gy is recommended for the phytosanitary irradiation treatment of papaya mealybug-infested commodities, ensuring a treatment efficacy of ≥99.9950% at 95% confidence level. Full article

The ham mite Tyrophagus putrescentiae and the red-legged ham beetle Necrobia rufipes are harmful pests to several high-valued stored products. The regulatory phase-out of the fumigant methyl bromide necessitates the search for alternative fumigants. Propylene oxide (PPO) and ethyl formate (EF) were therefore evaluated in the laboratory for controlling these pests of dry-cured hams. Concentration–mortality studies at 25 °C of PPO and EF found that the mobile stages of the mites were very susceptible to low concentrations of 10 mg/L and less of each gas, while mite eggs were very tolerant and required 20 mg/L for PPO and 80 mg/L of EF for 100% mortality. Mixed life stage cultures of mites and beetles were treated for 24 h with either PPO or EF at 1× and 2× the estimated 99% lethal doses and confirmed effectiveness for controlling simulated pest populations. The sorptive properties of each gas in chambers with ham pieces, dog food kibbles, or fish meal were minimal for a reduction in mite toxicity when compared to treatments in empty chambers. There was no evidence that any desorbed gas occurred at a level toxic to mite eggs in any of the fumigated commodities. These fumigation studies with ham pests support further work with PPO and EF on any changes in the sensory quality of dry-cured hams for human taste and for commercial-scale fumigations toward regulatory approval. Full article

Trialeurodes vaporariorum (Hemiptera: Aleyrodidae), commonly known as greenhouse whitefly, is one of the main insect pests of Oriental melon (Cucumis melo var L.) in South Korea. T. vaporariorum is of concern as a quarantine pest for the exportation of C. melo in Southeast Asian countries. Due to future restrictions on the use of methyl bromide (MB) during quarantine, ethyl formate (EF) represents a potential alternative. In this study, we evaluated EF for its efficacy (probit-9 values) in enabling the export of Oriental melons. The probit-9 value of EF for controlling T. vaporariorum was 3.02 g·h/m³ after 2 h of fumigation. We also assessed the phytotoxicity of EF on melons when using modified atmosphere packaging (MAP) under low-temperature conditions, which is required for export and trade, to extend shelf-life. In scaled-up trials, we found 8 g/m³ EF for 2 h at 5 °C to be suitable as a new phytosanitary treatment against greenhouse whitefly for exported Oriental melons when using MAP. No phytotoxic damage was found 28 d after fumigation at 5 °C in terms of five quality parameters (firmness, sugar content, mass loss, color change, and external damage). Full article

Sweet persimmons are a valuable export commodity. However, the presence of live insects such as Asiacornococcus kaki limits their access to many export markets. Methyl bromide, traditionally used for pest control, is damaging to human health and the environment. Ethyl formate (EF) is a viable alternative; however, its effectiveness against A. kaki on sweet persimmon fruit is unknown. We evaluated the effectiveness of EF fumigation in controlling A. kaki present under the calyx of persimmon fruit. The hatching rate of eggs and the survival rates of nymphs and adults of A. kaki at low temperatures, its LCt₅₀ and LCt₉₉ after EF exposure, and phytotoxic damage caused by EF were evaluated in laboratory-scale and commercial-scale tests. The dose–response tests showed that the EF LCt₉₉ at 5 °C was 9.69, 42.13, and 126.13 g h m⁻³ for adults, nymphs, and eggs, respectively. Commercial-scale tests demonstrated EF efficacy against all A. kaki stages without causing phytotoxic effects on persimmons, though the eggs of A. kaki were not completely controlled in linear low-density polyethylene (LLDPE)-packaged fruit. This study demonstrated that EF is a potential fumigant for quarantine pretreatment, especially before persimmon fruit is packed with LLDPE film, to control A. kaki infesting sweet persimmon fruit. Full article

Invasive snails and flies are major pests of imported orchids, controlled by methyl bromide (MB) fumigation in Korea. We compared the efficacy and phytotoxicity of ethyl formate (EF) and MB on four species of imported orchids using juvenile stages of Achatina fulica and third and fourth instars of Lycoriella mali. EF was as effective as MB. The LCt₉₉ values of EF were 68.1 and 73.1 g h/m³ at 15 °C; and those of MB were 95.9 and 78.4 g h/m³ at 15 °C for A. fulica and L. mali, respectively. In the scale-up trials, EF treatment at 35 g/m³ for 4 h at 15 °C resulted in complete control of both pests. MB treatment based on the current treatment guidelines for imported orchids (48 g/m³, 2 h, at >15 °C) resulted in complete control of L. mali but not of A. fulica. Chlorophyll content and hue values of treated orchids were not affected by EF treatment but significantly changed by MB (p-value < 0.05). All four treated species of orchids died within 30 d of MB treatment, while only one species died from EF treatment. Our results suggest that EF is a potential alternative to MB in phytosanitary treatment of imported orchids. Full article

The destructive effects of Fusarium wilts are known to affect the production of many crops. The control of Fusarium oxysporum and other soilborne pathogens was mainly based on soil fumigation (methyl bromide), which has long been prohibited and, nowadays, is based on a limited number of available fungicides due to legislation restrictions on residue tolerances and environmental impacts. Alternatively, natural and environmentally safe compounds, such as essential oils, are being investigated for their efficacy in the control of soilborne diseases. The great fungicidal ability of the oregano essential oil components (carvacrol and thymol) has been reported to inhibit the germination and the mycelial development of several fungal species, including F. oxysporum. The aim of our study was to demonstrate how the metabarcoding approach can provide valuable information about the positive or negative impacts of two different doses of oregano essential oil on Fusarium oxysporum and other fungal species which were present in the studied soil samples through the amplification of the ITS1 and ITS2 regions, which were analyzed on a MiSeq platform. A higher dose of oregano essential oil decreased the abundance of F. oxysporum, along with other fungal species, but also had negative effects on Trichoderma evansii and Mortierella chlamydospora, species with possible fungicidal properties. Soil properties, essential oil properties, the fungal composition, and interactions between fungal species should be considered as factors influencing the effectiveness of essential oils as biological control agents for soilborne pathogens. Full article