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Insects Jan 2023Invasive 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...
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.
PubMed: 36661994
DOI: 10.3390/insects14010066 -
Plants (Basel, Switzerland) Dec 2022The destructive effects of wilts are known to affect the production of many crops. The control of and other soilborne pathogens was mainly based on soil fumigation...
The destructive effects of wilts are known to affect the production of many crops. The control of 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 . 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 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 , along with other fungal species, but also had negative effects on and , 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.
PubMed: 36616191
DOI: 10.3390/plants12010062 -
Pest Management Science Apr 2023Ethanedinitrile (EDN) is a fumigant being commercialized worldwide as an alternative phytosanitary treatment to methyl bromide (MB) for forest products. The penetration...
BACKGROUND
Ethanedinitrile (EDN) is a fumigant being commercialized worldwide as an alternative phytosanitary treatment to methyl bromide (MB) for forest products. The penetration characteristics of MB and EDN were measured through the bark of wooden blocks (100 × 100 × 50 mm) cut from the upper (average bark thickness 5 ± 2 mm) and lower (average bark thickness 25 ± 5 mm) trunk of recently felled pine (Pinus radiata D.Don) trees. Doses of 48 g m MB and 50 g m EDN were applied to chambers at 10 and 20°C for 10 h.
RESULTS
Penetration of MB was influenced by the interaction between fumigation time and temperature, with concentrations increasing at a higher rate at 20°C compared with at 10°C. After 10 h, an average concentration of 8.05 ± 0.89 g m had penetrated the bark of log sections at 20°C, whereas 5.20 ± 0.89 g m was measured at 10°C. By contrast, the factors examined in this study did not significantly impact the penetration of EDN. Concentration × time (CT) values for MB under the bark were 35.20 ± 2.30 g h m at 10°C and 55.85 ± 9.58 g h m at 20°C; whereas for EDN, CT values were 19.50 ± 6.80 g h m at 10°C and 19.08 ± 4.10 g h m at 20°C.
CONCLUSION
MB can achieve a higher concentration under the bark of log sections during simulated fumigations, but all of the factors examined affected the ability of MB to penetrate the bark of wooden blocks. By comparison, the penetration of EDN through the bark is more consistent than MB under laboratory conditions. © 2022 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.
Topics: Pinus; Plant Bark; Pesticides
PubMed: 36495484
DOI: 10.1002/ps.7316 -
Plant Disease Jun 2023, 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...
, 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 U.S. markets have led to investigations of alternative strategies to control this pest. The efficacy of 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 under greenhouse and field conditions. The impact of the application of SME pre- or postplanting of was also determined. only induced hatch of and significantly fewer (up to 57 and 55% in pre- and postplant experiments, respectively) encysted eggs remained at termination of the experiment compared with the untreated control. However, when SME was applied preplant, the encysted eggs remained unchanged, which may indicate that SME inhibited egg hatch in the presence of . When applied individually, in all experiments, or SME at all rates tested in the greenhouse or 0.56 t/ha or higher rates of SME in the field, significantly reduced the viability, hatch, and reproduction of . Combined treatment with and SME at lower rates (0.14 t/ha for preplant or 0.56 t/ha or less for the greenhouse postplant experiment) reduced egg hatch further than each strategy alone. In the field, a combination of and SME at 1.12 t/ha or less reduced more effectively than SME alone. SME alone applied at higher rates (0.56 and 1.12 t/ha) in preplant greenhouse trials, whether or not combined with , eliminated reproduction. Under field conditions, SME applied at a rate of 1.12 t/ha highly reduced reproduction compared with the untreated control by 97 and 61% in 2019 and 2020, respectively. Furthermore, reproduction of was eliminated when SME was combined with . Our results indicated that a combination of SME and reduces the amount of SME needed to control and further decreases the potential reserve of the viable population remaining after individual treatment with each strategy.
Topics: Animals; Solanum; Mustard Plant; Solanum tuberosum; Soil; Tylenchoidea; Plant Extracts
PubMed: 36428258
DOI: 10.1094/PDIS-04-22-0758-RE -
Heliyon Nov 2022The gas-phase decomposition kinetics of isopropyl acetate (IPA) and its methyl, bromide and hydroxyl derivatives into the corresponding acid and propene were...
The gas-phase decomposition kinetics of isopropyl acetate (IPA) and its methyl, bromide and hydroxyl derivatives into the corresponding acid and propene were investigated using density functional theory (DFT) with the B97XD and M06-2x functionals, as well as the benchmark CBS-QB3 composite method. Transition state theory (TST) and RRKM theory calculations of rate constants under atmospheric pressure and in the fall-off regime were used to supplement the measured energy profiles. The results show that the formation of propene and bromoacetic acid is the most dominant pathway at the CBS-QB3 composite method, both kinetically and thermodynamically. There was a good agreement with experimental results. Pressures greater than 0.01 bar, corresponding to larger barrier heights are insufficient to ensure saturation of the measured rate coefficient when compared to the RRKM kinetic rates. Natural bond orbitals (NBO) charges, bond orders, bond indices, and synchronicity parameters all point to the considered pathways taking place via a homogenous, first-order concerted, as well as an asynchronous mechanism involving a non-planar cyclic six-membered transition state. The calculated data exhibit that the elongation of the C-O bond length and subsequent polarization of the C …O bond is the rate-determining step of the considered reactions in the cyclic transition state, which appears to be involved in this type of reaction.
PubMed: 36339763
DOI: 10.1016/j.heliyon.2022.e11274 -
Control of Using or 4-Hydroxybenzyl Alcohol with the Trap Crop or the Biofumigant Seed Meal Extract.Plant Disease May 2023The pale cyst nematode is a highly specialized, economically important pest for potato production. The specialized hatching requirements, ability to adapt, and the loss...
The pale cyst nematode 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 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 seed meal extract (SME) or 4-hydroxybenzyl alcohol (HBA), under laboratory and greenhouse conditions, enhances 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) following prior treatment with SME (0 and 4.48 t/ha) or HBA (0 and 0.12 t/ha) and (ii) 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 encysted eggs. alone reduced the number of encysted eggs compared to the nontreated control by up to 67%, indicating that this trap crop triggered eggs to hatch. When combined with SME or HBA, significantly reduced egg count, hatch rate, and viability more than alone. The combination of with HBA or SME eliminated reproduction on the susceptible potato. All the tested rates of SME alone or with HBA reduced egg hatch rate, viability, and reproduction compared to the nontreated control. Combining HBA and SME further significantly reduced egg hatch rate, viability, and reproduction than those rates of SME alone.
Topics: Mustard Plant; Sinapis; Solanum; Solanum tuberosum; Plant Extracts; Seeds
PubMed: 36320132
DOI: 10.1094/PDIS-06-22-1280-RE -
Journal of Occupational Medicine and... Oct 2022Fumigants are gaseous pesticides or biocides which eradicate pests by suffocation or poisoning. Worker exposure to fumigants is mainly via inhalation, followed by dermal... (Review)
Review
Fumigants are gaseous pesticides or biocides which eradicate pests by suffocation or poisoning. Worker exposure to fumigants is mainly via inhalation, followed by dermal contact and ingestion, leading to various acute and chronic health effects. Implementation of appropriate workplace controls such as adequate ventilation, training and personal protective equipment ensure that exposure to fumigants are kept to the lowest level as practically possible. In addition, routine medical examinations also allow for doctors to identify and manage possible exposure to fumigants and ascertain workers' fitness to work.While management guidelines after an acute exposure to such fumigants is clear and consistent, the guidelines on routine medical examination for fumigators is sparse. Components of the medical examinations vary according to the fumigant, workers are exposed to and its chronic health effects. Hence, this paper highlights the health hazards of commonly utilised fumigants; Methyl Bromide, Hydrogen Cyanide, Hydrogen Phosphide and Sulfuryl Fluoride; and outlines the guidance for routine medical examinations for exposed fumigators.
PubMed: 36307823
DOI: 10.1186/s12995-022-00361-3 -
Pathogens (Basel, Switzerland) Sep 2022The soil-borne pathogens, particularly f. sp. (FON) and southern root-knot nematode (RKN, ) are the major threats to watermelon production in the southeastern United...
The soil-borne pathogens, particularly f. sp. (FON) and southern root-knot nematode (RKN, ) are the major threats to watermelon production in the southeastern United States. The role of soil micronutrients on induced resistance (IR) to plant diseases is well-documented in soil-based media. However, soil-based media do not allow us to determine the contribution of individual micronutrients in the induction of IR. In this manuscript, we utilized hydroponics-medium to assess the effect of controlled application of micronutrients, including iron (Fe), manganese (Mn), and zinc (Zn) on the expression of important IR genes (, , and from salicylic acid (SA) pathway, and , , and genes from jasmonic acid (JA) pathway) in watermelon seedlings upon inoculation with either FON or RKN or both. A subset of micronutrient-treated plants was inoculated (on the eighth day of micronutrient application) with FON and RKN (single or mixed inoculation). The expression of the IR genes in treated and control samples was evaluated using qRT-PCR. Although, significant phenotypic differences were not observed with respect to the severity of wilt symptoms or RKN galling with any of the micronutrient treatments within the 30-day experimental period, differences in the induction of IR genes were considerably noticeable. However, the level of gene expression varied with sampling period, type and concentration of micronutrients applied, and pathogen inoculation. In the absence of pathogens, micronutrient applications on the seventh day, in general, downregulated the expression of the majority of the IR genes. However, pathogen inoculation preferentially either up- or down-regulated the expression levels of the IR genes at three days post-inoculation depending on the type and concentration of micronutrients. The results demonstrated here indicate that micronutrients in watermelon may potentially make watermelon plants susceptible to infection by FON and RKN. However, upon infection the IR genes are significantly up-regulated that they may potentially aid the prevention of further infection via SA- and JA-pathways. This is the first demonstration of the impact of micronutrients affecting IR in watermelon against FON and RKN infection.
PubMed: 36297194
DOI: 10.3390/pathogens11101136 -
The Journal of International Medical... Oct 2022Methyl bromide is a pre-plant soil fumigant that is widely used to control nematodes, insects, and fungi in farmlands. Methyl bromide enters the human body through...
Methyl bromide is a pre-plant soil fumigant that is widely used to control nematodes, insects, and fungi in farmlands. Methyl bromide enters the human body through dermal absorption or inhalation and can damage the respiratory, nervous, circulatory, urinary, and other systems. A 62-year-old man who had inhaled a large amount of methyl bromide was admitted to our department. He presented with respiratory failure and pink foamy sputum. He was started on dexamethasone, alanyl glutamine, sulbactam, furosemide, vitamin B, mouse nerve growth factor, and other treatments, and mechanical ventilation and continuous venovenous hemodiafiltration (CVVHF) were performed daily. He subsequently developed coagulopathy because of the CVVHF, for which protamine, recombinant human brain natriuretic peptide, and albumin were administered intravenously. Notably, the patient developed sustained anuria and eventually died owing to multiple organ failure; specifically, failure of the brain, heart, lungs, and kidneys. This report presents the diagnosis, clinical course, management, and prognosis of a patient who was treated at our hospital for severe methyl bromide poisoning.
Topics: Acute Kidney Injury; Albumins; Animals; Anuria; Dexamethasone; Furosemide; Glutamine; Humans; Hydrocarbons, Brominated; Male; Mice; Middle Aged; Natriuretic Peptide, Brain; Nerve Growth Factors; Protamines; Soil; Sulbactam; Vitamins
PubMed: 36250482
DOI: 10.1177/03000605221122619