Methyl Bromide Fumigation Research Articles

Sorption and residue analysis of phosphine in fruits and vegetables

ABSTRACT This study investigated the sorption and residues of phosphine in fruits and vegetables relevant for export. Sorption patterns varied among the commodities: mango exhibited a constant sorption range of 10–12%, bitter gourd displayed a distinct pattern with peak sorption of 20% at 8 hours, and chilli demonstrated a higher range of sorption percentage, peaking at 60% at 8 hours. ANOVA (F (4,8) = 0.449, p = 0.771) and regression (F (1,11) = 0.851, p = 0.376) analysis revealed a non-significant relationship between the sorption percentage and exposure period. Residue analysis using Gas Chromatography with FPD detector revealed relatively low levels of phosphine residues in mango (0.009–0.01 µL/L), negligible traces in chilli samples, residues within the maximum residue limit (MRL) range for bitter gourd after 4–6 hours of aeration. Detecting phosphine residues within acceptable limits underscores the significance of post-fumigation protocols to meet stringent food safety standards, thereby safeguarding product integrity for global trade. Therefore, phosphine fumigation could serve as a viable alternative to methyl bromide fumigation for quarantine treatment of perishables as it doesn’t leave detectable toxic residues in produce following aeration and has no role in ozone depletion thus making it a more sustainable solution for international trade in fresh produce.

Biochar combined with humic acid improves the soil environment and regulate microbial communities in apple replant soil

Apple replant disease (ARD) negatively affects plant growth and reduces yields in replanted orchards. In this study, biochar and humic acid were applied to apple replant soil. We aimed to investigate whether biochar and humic acid could promote plant growth and alleviate apple replant disease by reducing the growth of harmful soil microorganisms, changing soil microbial community structure, and improving the soil environment. This experiment included five treatments: apple replant soil (CK), apple replant soil with methyl bromide fumigation (FM), replant soil with biochar addition (2 %), replant soil with humic acid addition (1.5 ‰), and replant soil with biochar combined with humic acid. Seedling biomass, the activity of antioxidant enzymes in the leaves and roots, and soil environmental variables were measured. Microbial community composition and structure were analyzed using ITS gene sequencing. Biochar and humic acid significantly reduced the abundance of Fusarium and promoted the recovery of replant soil microbial communities. Biochar and humic acid also increased the soil enzymes activity (urease, invertase, neutral phosphatase, and catalase), the plant height, fresh weight, dry weight, the activity of antioxidant enzymes (superoxide dismutase, peroxidase, and catalase), and root indexes of apple seedlings increased in replant soil. In sum, We can use biochar combined with humic acid to alleviate apple replant disease.

Impacts of the Ban on the Soil-Applied Fumigant Methyl Bromide.

The loss of the soil fumigant methyl bromide (MeBr) and adoption of soil fumigant alternatives has been challenging for farmers, particularly for those crops in which pathogens previously controlled by MeBr have emerged as significant problems, but it has resulted in some unanticipated benefits for the scientific community and the environment. Applauded as one of the most effective environmental agreements to date, the universally accepted Montreal Protocol on Ozone Depleting Substances has had a significant impact on the environment, reducing the release of halogenated compounds from anthropogenic sources enough to mitigate global warming by an estimated 1.1°C by 2021. The funding associated with various MeBr transition programs has increased collaboration across scientific disciplines, commodity groups, industry, and regulatory agencies. Chemical alternatives and improved application strategies, including the development of gas-retentive agricultural films, coupled with sound efficacy data and grower ingenuity have resulted in the sustained production of many of the impacted crops; although there has been some loss of acreage and value, particularly for Florida fumigated crops, for some, value has continued to increase, allowing production to continue. The loss of a single, broad-spectrum tool for pest control has led to a deeper understanding of the specific pest complexes impacting these at-risk crops, as well as the development of new, biologically based management tools for their control while increasing our understanding of the role of the soil microbiome in pest control and crop production.

Ethyl Formate Fumigation against Pineapple Mealybug, Dysmicoccus brevipes, a Quarantine Insect Pest of Pineapples.

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 LCt99, 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.

Uses and commercialization of food grade and effectiveness of coated ham nets to combat Tyrophagus putrescentiae: a review

Since the 1930s, the dry-cured ham industry has used methyl bromide fumigation to control Tyrophagus putrescentiae (ham mite) infestations. However, due to methyl bromide being a class I ozone depleting substance and no longer being manufactured, alternatives to methyl bromide have been studied extensively. Direct contact food-grade coatings and coated ham nets of various materials have shown efficacy in controlling ham mite growth and reproduction. These coated nets, often including propylene glycol, can be dried to ease application and reduce shipping cost, but chemical and thermal treatments on fabrics may cause the fabrics to become more brittle, which negatively impacts stretchability and bursting strength, and ultimately the effectiveness of the net. Scanning electron microscopy can provide precise visual inspection of fabric surface morphology, allowing for a detection of potential damage to the fibers. This purpose of this review is to summarize the application of food-grade coatings on nets used in the dry-cured ham industry to control mite infestations. More importantly, the review provides comprehensive information on coated nets, covering various aspects such as the selection of netting materials, evaluation of fabric properties, techniques for coating nets, net drying method, all in relation to their efficacy for mite control. This review contributes to the broad area of this applied technology by highlighting efficacious treatments to control mites, ineffective treatments, a discussion of processes to evaluate their properties, and future prospectives regarding this area of study.

Crop bromide concentrations following methyl bromide fumigation for pale cyst nematode in southeastern Idaho.

Methyl bromide (MeBr) is a sterilizing fumigant used to control quarantine pests that is restricted due to its detrimental atmospheric effects. The degradation of injected MeBr produces crop-available Br- . Up to five applications of MeBr were used in southeastern Idaho fields to combat the pale cyst nematode (Globodera pallida). Data regarding the uptake and partitioning of Br- in crops following MeBr application in the region were unavailable. Research determined background concentrations of Br- in alfalfa (Medicago sativa L.), barley (Hordeum vulgare L.), corn (Zea mays L.), potato (Solanum tuberosum L.), and wheat (Triticum aestivum L.) compared to MeBr-treated fields. Background Br- concentrations ranged from nondetectable (ND) to 33.0mg Br- kg-1 ; vegetative tissue concentrations were greater than reproductive, except corn where there was no difference. Nearly all crops grown in MeBr-treated fields had greater Br- concentrations than background. Background-baled-alfalfa tissue Br- concentration was 33.0mg kg-1 compared to 117.8mg Br- kg-1 from a MeBr-treated field. Br- concentration in green alfalfa decreased from 79.8 to 36.5mg Br- kg-1 at the final cutting in a MeBr-treated field, where time after application decreased crop Br- concentrations. Small grains had low Br- concentrations in reproductive tissue (1.7mg Br- kg-1 ) compared to vegetative tissue (106.5mg Br- kg-1 ). Corn stover concentration (12.7mg Br- kg-1 ) was low relative to small-grain straw, but corn ear (5.8mg Br- kg-1 ) was greater than small-grain reproductive tissue in the MeBr-treated field. Crop selection following MeBr applications should consider the likelihood of elevated Br- concentration for the plant fractions intended end use.

Grafting Tomato to Manage Southern Blight, Prevent Yield Loss, and Increase Crop Value.

Southern blight, caused by the soilborne fungus Athelia rolfsii, has increased in frequency and severity in the southern United States since the use of methyl bromide fumigation ceased. The objective of this study was to evaluate three cultivars of sticky nightshade (Solanum sisymbriifolium), previously used as tomato rootstocks because of resistance to root-knot nematode, for resistance to southern blight. Field experiments in infested soil were done in Georgia in 2020 and 2021 and in South Carolina in 2021. Tomato cultivar Roadster was used as the scion. Control treatments included non-grafted Roadster in all experiments and self-grafted Roadster in Georgia. In all three experiments, all rootstocks significantly reduced incidence of southern blight and increased vigor ratings compared to control treatments (P ≤ 0.007). The rootstocks Maxifort, White Star, and SisSynII, but not Diamond, significantly increased marketable weight (P ≤ 0.02) and crop value (P < 0.05) compared to control treatments. In South Carolina only, because of greater yields than in Georgia, net returns with Maxifort and White Star were significantly greater than net return with non-grafted Roadster (P = 0.004). When the wholesale price for fresh market tomato is ≥$13/box, grafting may be an effective and economical management for southern blight.

Biochar alleviates apple replant disease by reducing the growth of Fusarium oxysporum and regulating microbial communities

Apple replant disease (ARD) negatively affects plant growth and reduces yields in replanted orchards. In this study, biochar was applied to apple replant soil with Fusarium oxysporum. Our aim was to investigate whether biochar could promote plant growth and alleviate apple replant disease by reducing the growth of harmful soil microorganisms, changing soil microbial community structure and improving the soil environment. This experiment included five treatments: apple replant soil (CK), methyl bromide fumigation apple replant soil (FM), replant soil with biochar addition (2%), replant soil with F. oxysporum spore solution (8 × 107 spores · mL−1), and replant soil with biochar and F. oxysporum spore solution addition. Seedling biomass, the activity of antioxidant enzymes in the leaves and roots, and soil environmental variables were measured. Microbial community composition and community structure were analyzed using 16S rDNA and ITS2 gene sequencing. Biochar significantly reduced the abundance of F. oxysporum and increased soil microbial diversity and richness. Biochar also increased the soil enzyme activities (urease, invertase, neutral phosphatase, and catalase), the biomass (plant height, fresh weight, dry weight) and the activity of antioxidant enzymes (superoxide dismutase, peroxidase, and catalase). The root indexes of apple seedlings was also increased in replant soil by biochar. In sum, biochar promoted the growth of plants, improved the replant soil environment, and alleviated apple replant disease.

Comparison of fumigation efficacy of methyl bromide alone and phosphine applied either alone or simultaneously or sequentially against Bactrocera correcta in Selenicereus undatus (red pitaya) fruit.

Bactrocera correcta (Bezzi) is a significant pest of the red pitaya fruit (Selenicereus undatus). This study investigated the insecticidal effects of methyl bromide (MB) alone, phosphine (PH3 ) alone, both applied simultaneously (PH3 + MB), and PH3 application followed sequentially by MB (PH3 → MB) against B. correcta in red pitaya fruits. The 3rd instar larvae of B. correcta were the most tolerant to MB alone and the combined treatments, whereas eggs were the most susceptible stage. Both the PH3 + MB and PH3 → MB treatments resulted in higher mortality at all stages than MB alone, demonstrating a synergistic effect between MB and PH3 . The toxicity of the combined treatments increased with increasing PH3 concentrations, with the optimal concentration recorded being 1.42 to 2.84 g m-3 . Further probit analysis revealed that compared to the MB treatment alone, the median lethal dose values of MB in PH3 + MB and PH3 → MB treatment, were reduced to 63.73% and 66.82%, respectively. Fruit quality was not adversely affected by either of the combined treatments. This work provides robust evidence that combining MB and PH3 to control B. correcta is highly effective, especially the PH3 → MB treatment. This combination decreased the amount of MB required for effective control at all life stages, while protecting fruit quality against MB phytotoxicity to a greater extent than conventional MB fumigation alone. © 2023 Society of Chemical Industry.

Phosphine estimation in fumigated food grains using gas chromatography equipped with FPD detector.

Phosphine, as per several reports, is considered to be an ideal and effective alternative to methyl bromide (MB) fumigant, phased out globally honouring 'Montreal Protocol'. The food grains fumigated with phosphine are perceived to be residue-free; however, estimation of its residues is imperative. In the present study, the phosphine residues were estimated in grains of wheat, rice, green gram, chickpea and yellow pea fumigated with different formulations of phosphine under 7 and 10days exposure periods at various locations in India. For efficacy studies, the conventional aluminium phosphide (AlP) tablet (56% @2 and 3 tablet/MT) and granular AlP (77.5% @1.0 and 1.5g phosphine/m3) formulations were applied. Each treatment including untreated control was replicated thrice. The concentration was monitored every 24h until the end of exposure periods. Food grain samples were drawn before and post fumigation following a certain waiting period for estimation of phosphine residues using gas chromatography equipped with FPD detector. Residues in fumigated food grains were observed in traces in all the experimental stacks, but below the MRL (0.1ppm), fixed by Codex Alimentarius Commission (CAC). Phosphine can be considered safe for use as an alternate fumigant in quarantine and long-term storage of food grains leaving residues below MRL.

Quarantine Disinfestation of Papaya Mealybug, Paracoccus marginatus (Hemiptera: Pseudococcidae) Using Gamma and X-rays Irradiation.

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 LD99.9968 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.

Efficacy of a carboxymethylcellulose (CMC)-based edible film with propylene glycol to control ham mite populations that infest dry cured ham

Dry-cured hams are susceptible to ham mite, Tyrophagus putrescentiae (Schrank) (Sarcoptiformes: Acaridae), infestations during the aging process. Methyl bromide (MB) fumigation has been used to control mites from infesting hams. However, MB is an ozone depleting substance that is both expensive and scarce, so alternative control methods must be discovered. The objective of this research was to determine the efficacy of using an edible film to control or reduce mite growth and reproduction on dry-cured hams. The edible films consist of water, 1% of carboxymethylcellulose (CMC), and propylene glycol (PG), which was included at five concentrations: 0%, 5%, 10%, 15%, and 20%. The resulting films’ ability to reduce mite infestation was tested against two control groups: exposed ham cubes (negative control) and ham cubes wrapped in polyester nets (positive control) containing 40% PG, 1% carrageenan, and 1% propylene glycol alginate. Two weeks after inoculation with 20 mites, all film treatments had fewer (P < 0.05) mites than the negative control (262-mites). Film treatments with 0% (24-mites), 5% (26-mites), and 10% PG (17 mites) were effective at slowing mite reproduction, but not to the extent of the positive control (0-mites), 15% (6-mites), and 20% (1-mite) PG films as evidenced by a linear decrease in mite counts (F1 = 19.22, P < 0.0001) as PG concentration increased. Water Vapor Transmission (WVT) and Oxygen Permeability (OP) results indicated that all films exhibited substantial breathability with values ranging from 805 g m−2 day−1 to 899 g m−2 day−1 for WVT and 355 cc m−2 day−1 to 3413 cc m−2 day−1 for OP. Sensory analysis results indicated that the film treatments did not alter the sensory properties of the treated hams when compared to the untreated control. Further studies will include application of films to whole hams during aging and improved manufacturing techniques for films.

Control of Globodera pallida Using Brassica juncea Seed Meal Extract and the Trap Crop Solanum sisymbriifolium.

Globodera pallida, the pale cyst nematode, is a regulated potato pest which is economically detrimental. Restrictions on use of the soil fumigant methyl bromide, and lack of resistant russet type varieties for US markets have led to investigations of alternative strategies to control this pest. The efficacy of Brassica juncea seed meal extract (SME) (0, 0.14, 0.28, 0.56, 1.12, and 2.24 t/ha) was studied, either alone or in combination with the trap crop Solanum sisymbriifolium under greenhouse and field conditions. The impact of the application of SME pre- or post-planting of S. sisymbriifolium was also determined. Solanum sisymbriifolium only induced hatch of G. pallida and significantly fewer (up to 57 and 55% in pre- and post-plant experiments, respectively) encysted eggs remained at termination of the experiment compared to the untreated control. However, when SME was applied pre-plant, the encysted eggs remained unchanged which may indicate that SME inhibited egg hatch in the presence of S. sisymbriifolium. When applied individually, S. sisymbriifolium in all experiments, or SME at all rates tested in greenhouse and 0.56 t/ha or higher rates of SME in the field significantly reduced the viability, hatch, and reproduction of G. pallida. Combined treatment with S. sisymbriifolium and SME at lower rates, 0.14 t/ha for pre-plant or 0.56 t/ha or less for the greenhouse post-plant experiment further reduced G. pallida egg hatch than each strategy alone. In the field, a combination of S. sisymbriifolium and SME at 1.12 t/ha or less reduced G. pallida more effectively than SME alone. SME alone applied at higher rates of 0.56 and 1.12 t/ha in pre-plant greenhouse trials, whether combined with S. sisymbriifolium, eliminated G. pallida reproduction. Under field conditions, SME applied at a rate of 1.12 t/ha highly reduced G. pallida reproduction compared to the untreated control by 97% and 61% in 2019 and 2020, respectively. Furthermore, reproduction of G. pallida was eliminated when SME was combined with S. sisymbriifolium. Our results indicated that a combination of SME and S. sisymbriifolium reduces the amount of SME needed to control G. pallida and further decreases the potential reserve of the viable population remaining after individual treatment with each strategy.

Efficacy of the Fumigants Propylene Oxide and Ethyl Formate to Control Two Pest Species of Dry-Cured Hams

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.

Oak Wilt Fungus (Bretziella fagacearum) Survival in Logs Following Fumigation with Ethanedinitrile

Abstract The phaseout of methyl bromide (MB) fumigation creates an urgent need for an alternative phytosanitary treatment to limit the risk of international spread of the oak wilt fungus, Bretziella fagacearum. Fumigation with ethanedinitrile (EDN) is considered a potential alternative to MB fumigation to eradicate wood-inhabiting pests and pathogens. We evaluated the efficacy of EDN fumigation by comparing the rate of B. fagacearum isolation before and after fumigation of red oak (Quercus rubra or Quercus ellipsoidalis) log sections from oak wilt–affected trees. Logs (range 15.2 to 98.0 cm long; diameter 9.1 to 46.1 cm) were obtained from red oak trees that were naturally infected (NI) or artificially inoculated (AI) with B. fagacearum. The logs were fumigated for 24, 48, and/or 72 hours with 120 g/m3 EDN. Frequencies of pathogen isolation from the sapwood before treatment were higher for AI logs than for NI logs. EDN treatments greatly reduced the frequency of viable pathogen recovery, but eradication occurred only in experiments using the smallest log diameters (9 to 14 cm). Our results suggest that EDN may have limited penetration in oak logs with intact bark, similar to fumigants currently used on wood products, such as MB and sulfuryl fluoride. Results of future work may help in the understanding of the limitations for consistent and full efficacy of EDN against B. fagacearum in logs harvested from diseased trees.

Control of Globodera pallida Using Sinapis alba or 4-Hydroxybenzyl Alcohol with the Trap Crop Solanum sisymbriifolium or the Biofumigant Brassica juncea Seed Meal Extract.

The pale cyst nematode Globodera pallida is a highly specialized, economically important pest for potato production. The specialized hatching requirements, ability to adapt, and the loss of effective control strategies such as methyl bromide fumigation increase the challenge to eradicate G. pallida in Idaho. Without a suitable host, this nematode can remain dormant as encysted eggs in soil for up to 20 years. In this study, we first demonstrated that Sinapis alba seed meal extract (SME) or 4-hydroxybenzyl alcohol (HBA), under laboratory and greenhouse conditions, enhances G. pallida egg hatch rate when exposed to potato root diffusate (PRD). This hatch rate enhancement in the presence of PRD is speculated to be due to an increase in egg-shell permeability. We then tested the efficacy of (i) Solanum sisymbriifolium following prior treatment with S. alba SME (0 and 4.48 t/ha) or HBA (0 and 0.12 t/ha) and (ii) Brassica juncea SME (0, 0.14, 0.56, and 1.12 t/ha) following HBA treatment (0 and 4.48 t/ha) on egg viability, hatch rate, and reproduction of G. pallida encysted eggs. S. sisymbriifolium alone reduced the number of encysted eggs compared to the nontreated control by up to 67%, indicating that this trap crop triggered G. pallida eggs to hatch. When combined with S. alba SME or HBA, S. sisymbriifolium significantly reduced egg count, hatch rate, and viability more than S. sisymbriifolium alone. The combination of S. sisymbriifolium with HBA or S. alba SME eliminated G. pallida reproduction on the susceptible potato. All the tested rates of B. juncea SME alone or with HBA reduced egg hatch rate, viability, and reproduction compared to the nontreated control. Combining HBA and B. juncea SME further significantly reduced egg hatch rate, viability, and reproduction than those rates of B. juncea SME alone.

Application of Integrated Postharvest Technology for Maintaining the Quality of Methyl Bromide Fumigated Mangosteen Fruit

Methyl bromide fumigation aims to control insect infestation in mangosteen fruit before export which leads to reduce the fruit quality. Thus, the objective of this study was to control the quality of methyl bromide fumigated mangosteen using integrated postharvest technology. Fruit were prepared by fumigating with 32 g m-3 for 2 hours, washed with tap water, surfaced disinfestation with sodium hypochlorite. The prepared fruit samples were divided to treat with different methods as follows; 1) fruit were coated with ethanolic shellac-modified coconut oil (ES-MCO) and then packed in low density polyethylene (LDPE) bag containing ethylene inhibitor (1-MCP sachet), 2) fruit were coated with ES-MCO and packed in LDPE bag, 3) fruit were treated with ES-MCO and packed in nylon net bag, and 4) fruit were non-coated and packed in nylon net bag (control). All fruit samples were kept at 13ºC for 20 days (as the shipment stimulation) and then transferred to 25ºC for 2 days (as the shelf-life stimulation). The results revealed that after 15 days of storage fruit were treated with ES-MCO + LDPE bag + 1-MCP sachet showed the highest reduction of fruit rot disease and this treatment helped to delay the drying and browning of mangosteen calyx, chlorophyll degradation of the calyx, and reduce weight loss, the respiration rate and ethylene production. However after storage for 20 days, the pericarp of mangosteen in fruit treated with ES-MCO + LDPE bag + 1-MCP sachet became hard, and its shelf-life was 15 days.

International supply chain handling practices and the quality of heat-treated, white oak veneer logs

The most promising alternative to the methyl bromide fumigation of exported logs is steam-heating the log in a vacuum. Research has confirmed that steam heating to 56 °C for 30 minutes kills all viable propagules of oak wilt pathogen (Bretziella fagacearum) in the sapwood of oak logs. The purpose of this study was to determine whether this heat-treatment method has any effect on the quality or value of white oak veneer logs shipped between the US and EU. Seventeen steam- and vacuum-treated and seventeen untreated control logs were shipped from Baltimore, Maryland to the Czech Republic, for processing into veneer, between December 2021 and February 2022. The treated and untreated logs were sawn into flitches, soaked in hot water vats, sliced, dried, and the veneer from each log was graded for quality. Each log was assigned a value based on the veneer quality and yield. The average value of treated log was 1,547 €/m³, and the average value of the untreated logs was 1,539 €/m³. The null hypothesis was statistically confirmed. Therefore, it is concluded that the 56 °C/30 min, sapwood heat treatment using vacuum and saturated steam had no adverse impact on the value of the white oak veneer logs.

Effect of Hydrogen Peroxide on the Soil Microbial Community Structure and Growth of Malus hupehensis Rehd. Seedlings under Replant Conditions.

Apple replant disease (ARD) is common in apple production, which seriously affects the growth and development of apples. In this study, hydrogen peroxide with a bactericidal effect was used to treat the replanted soil, and the effects of different concentrations of hydrogen peroxide on replanted seedlings and soil microbiology were investigated in order to seek a green, clean way to control ARD. Five treatments were set up in this study: replanted soil (CK1), replanted soil with methyl bromide fumigation (CK2), replanted soil + 1.5% hydrogen peroxide (H1), replanted soil + 3.0% hydrogen peroxide (H2), and replanted soil + 4.5% hydrogen peroxide (H3). The results showed that hydrogen peroxide treatment improved replanted seedling growth and also inactivated a certain number of Fusarium, while the Bacillus, Mortierella, and Guehomyces also became more abundant in relative terms. The best results were obtained with replanted soil + 4.5% hydrogen peroxide (H3). Consequently, hydrogen peroxide applied to the soil can effectively prevent and control ARD.

Comparison of Methyl Bromide and Ethyl Formate for Fumigation of Snail and Fly Pests of Imported Orchids.

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 &gt;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 &lt; 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.