-
Insects Aug 2021The fumigant pesticide methyl bromide (MB) was used for stored products, but it is now banned for most uses in many countries as an ozone-depleting substance. MB was the...
The fumigant pesticide methyl bromide (MB) was used for stored products, but it is now banned for most uses in many countries as an ozone-depleting substance. MB was the only pesticide used to manage the ham mite, , which is the most significant pest of dry cured hams. Effective alternatives to MB are needed to develop integrated pest management (IPM) programs for this pest. This study evaluated plant essential oils and food-safe compounds as repellents to directly protect hams from infestation. Experiments to assess the repellency to orientation, oviposition, and population growth of mites on pieces of aged country hams were conducted. Test compounds at different concentrations were dissolved in respective solvents and compared to the solvent control. Results showed that C8910, a mixture of three short-chain fatty acids, and the sesquiterpene ketone nootkatone had repellency indices of (RI) of 85.6% and 82.3%, respectively, at a concentration of 0.1 mg/cm, when applied to a Petri dish arena. DEET and icaridin were also tested but performed poorly with RIs below 70% even at 0.1 mg/cm.The monoterpene alcohol geraniol had the highest RI of 96.3% at 0.04 mg/cm. Ham pieces dipped in C8910 and nootkatone at 150 ppm each had RIs of 89.3% and 82.8%, respectively. In general, as the concentrations of test compounds increased, the numbers of eggs that were laid on these treated ham cubes decreased after the 48 h exposure time. Ham pieces dipped in different concentrations of test compounds and then inoculated with 20 adult mites showed a significant decrease in mite population growth compared to control pieces after 14 days. The results of these experiments suggest that some plant secondary metabolites and synthetic food-safe compounds could serve as potential alternatives for managing mites on hams.
PubMed: 34442277
DOI: 10.3390/insects12080711 -
Environmental Monitoring and Assessment Aug 2021
PubMed: 34387752
DOI: 10.1007/s10661-021-09246-0 -
Agricultural Pesticides and Shingles Risk in a Prospective Cohort of Licensed Pesticide Applicators.Environmental Health Perspectives Jul 2021Some pesticides are immunotoxic and have been associated with an increased risk of immune-mediated diseases. The risk of shingles, the clinical reactivation of...
BACKGROUND
Some pesticides are immunotoxic and have been associated with an increased risk of immune-mediated diseases. The risk of shingles, the clinical reactivation of varicella-zoster virus, increases with aging and immunosuppression; little is known about its associations with pesticides.
OBJECTIVE
We examined the use of agricultural pesticides in relation to incident shingles in a prospective cohort of licensed pesticide applicators.
METHODS
The study sample included 12,820 (97% male) farmers (enrolled in 1993-1997 in North Carolina and Iowa), who were followed for a median of 12 y (interquartile range: 11-13). Shingles was self-reported at enrollment and at follow-up. We evaluated ever-use of 48 agricultural pesticides reported at study enrollment in relation to shingles risk and considered exposure-response for intensity-weighted lifetime days (IWLDs) of use. Hazard ratios (HRs) and 95% confidence intervals (CIs) were calculated using Cox proportional hazard models, adjusting for state, and allowing estimates to vary by median attained age (60 y).
RESULTS
Incident shingles was reported by 590 participants. Associations were positive () for ever- vs. never-use of eight insecticides, three fumigants, two fungicides, and five herbicides, and exposure-response trends were seen across increasing quartiles (Q3 and ) or tertiles (T3 and ) of IWLDs for four insecticides [permethrin (crops), coumaphos, malathion, and lindane], two fumigants (carbon tetrachloride/carbon disulfide and methyl bromide), and three herbicides [alachlor, trifluralin () and 2,4-dichlorophenoxyacetic acid]. Shingles was not associated with total years or days per year mixed or applied any pesticides, but in older participants, shingles was associated with a history of a high pesticide exposure event [ (95% CI: 1.45, 2.45)].
CONCLUSIONS
Several specific pesticides were associated with increased risk of shingles in farmers, especially at higher levels of cumulative use. These novel findings, if replicated in other populations, could have broader implications for the potential effects of pesticides on vaccine efficacy and susceptibility to other infections. https://doi.org/10.1289/EHP7797.
Topics: Aged; Agriculture; Female; Herpes Zoster; Humans; Iowa; Male; North Carolina; Occupational Exposure; Pesticides; Prospective Studies
PubMed: 34319145
DOI: 10.1289/EHP7797 -
Pathogens (Basel, Switzerland) Jun 2021Zinc (Zn) accumulation and deficiency affect plant response to pests and diseases differently in varying pathosystems. The concentrations of Zn in plants aid in priming...
Zinc (Zn) accumulation and deficiency affect plant response to pests and diseases differently in varying pathosystems. The concentrations of Zn in plants aid in priming defense signaling pathways and help in enhanced structural defenses against plant pathogens. Studies are lacking on how concentrations of Zn in watermelon plants influence defense against two important soil-borne pathogens: f. sp. (FON) and southern root-knot nematode (RKN, ). In this study a comparative transcriptomics evaluation of watermelon plants in response to high (1.2 ppm) and low (0.2 ppm) levels of Zn were determined. Differential transcript-level responses differed in watermelon plants when infected with FON or RKN or both under high- and low-Zn treatment regimes in a controlled hydroponics system. Higher numbers of differentially expressed genes (DEGs) were observed in high-Zn-treated than in low-Zn-treated non-inoculated plants, in plants inoculated with FON alone and in plants inoculated with RKN alone. However, in the co-inoculated system, low-Zn treatment had higher DEGs as compared to high-Zn treatment. In addition, most DEGs were significantly enriched in hormone signal transduction and MAPK signaling pathway, suggesting an induction of systemic resistance with high-Zn concentrations. Taken together, this study substantially expands transcriptome data resources and suggests a molecular potential framework for watermelon-Zn interaction in FON and RKN.
PubMed: 34201638
DOI: 10.3390/pathogens10070796 -
ACS Omega Jun 2021Halogen-halogen nonbonded interactions were studied for methyl halides and phenyl halides using both B3LYP and MP2 along with 6-311+G* and aug-cc-pVTZ. With the methyl...
Halogen-halogen nonbonded interactions were studied for methyl halides and phenyl halides using both B3LYP and MP2 along with 6-311+G* and aug-cc-pVTZ. With the methyl halides, the linear approach was found to lead to little stabilization, whereas the "90°" approach gave 1-2 kcal/mol. This modest stabilization was due to long-range electron correlation effects. The lowest-energy arrangement had the molecules side-by-side, with the major stabilization being derived from halogen-hydrogen interactions. The results for methyl bromide were quite similar. Chlorobenzene dimer with the 90° orientation gave a small stabilization energy, but the best arrangement had the two benzene rings oriented over each other. The meta orientation of the chlorines had a lower energy than ortho or para. The dimerization energy was larger than that for two benzene rings sitting directly above each other, suggesting that whereas Cl···Cl interaction is not very important, the effect of the halogen on the electron distribution does have an effect. This suggests that much of the crystallographic results for these compounds may not be due to halogen-halogen interactions but rather the interaction between the substituted benzene rings along with crystal forces.
PubMed: 34151099
DOI: 10.1021/acsomega.1c01356 -
Environmental Monitoring and Assessment Jun 2021Methyl bromide (MB) is a highly toxic and ozone-depleting substance and should be replaced. Worker exposure to high MB concentrations during fumigation has been...
Methyl bromide (MB) is a highly toxic and ozone-depleting substance and should be replaced. Worker exposure to high MB concentrations during fumigation has been previously reported. However, variations in MB concentration as a function of distance from fumigated objects or of time after degassing have not been reported so far. In this study, air samples were collected at various distances from fumigated objects (oranges, wood in containers, and wood in tarpaulin) during injection and degassing and analyzed via gas chromatography according to the Occupational Safety and Health Agency method. In addition, MB concentrations were directly measured over time using a gas detector during degassing. Non-linear regression analysis of the logarithmically transformed data indicated a clear decrease in MB concentration with distance as well as time. Non-linear regression models were constructed to describe the decrease in MB concentration with distance from the objects and with time during degassing (P < 0.05 for all models). The results of this study could aid in establishing appropriate safety guidelines, and hence, in preventing risks related to MB exposure.
Topics: Environmental Monitoring; Fumigation; Hydrocarbons, Brominated; Quarantine
PubMed: 34105044
DOI: 10.1007/s10661-021-09154-3 -
Insects May 2021The khapra beetle, Everts, is defined as one of the most important quarantine pests globally, and fumigation with methyl bromide, an ozone-depleting substance, is a...
The khapra beetle, Everts, is defined as one of the most important quarantine pests globally, and fumigation with methyl bromide, an ozone-depleting substance, is a common phytosanitary measure currently used. The modified atmosphere (MA), irradiation, and their combination treatments of . larvae and adults were performed at room temperature (24-26 ℃) to develop an ecofriendly phytosanitary disinfestation measure and to shorten the exposure time and overcome treatment disadvantages of irradiation. Late-stage larvae are determined as the most tolerant stage resulted in large LT values of 32.6 (29.2-37.5) and 38.0 (35.1-41.7) days treated under 1% and 2% O (with N balance) atmosphere, respectively. Ionizing radiation was used to enhance the effect of MA and the mortality was highly significantly affected by all the interaction effects, indicating that the synergistic effects present in all the combined treatments. The synergistic ratios, which is defined as the estimated lethal time for MA treatment (LD, LD, and LD), divided by that of combined treatment, were between 1.47 and 2.47. In the confirmatory tests, no individuals recovered from a sum of 111,366 late-stage larvae treated under 1% O atmosphere for 14- or 15-d after 200 Gy irradiation, which resulted in validating the probit estimations and achieving an efficacy of 99.9973% mortality at 95% confidence level. Therefore, these treatment schedules are recommended to disinfest . infecting commodities for phytosanitary purposes under the warehouse, MA packaging, or in combination with international transportation by train or sea container.
PubMed: 34066268
DOI: 10.3390/insects12050442 -
Journal of Nematology 2021Fumigant use in perennial crops can be reduced through prolonging the life of existing orchards. The longer an orchard remains healthy and productive, the less often it...
Fumigant use in perennial crops can be reduced through prolonging the life of existing orchards. The longer an orchard remains healthy and productive, the less often it will be terminated, fumigated, and replanted. Two trials were conducted to determine the effectiveness of DiTera, a toxin produced by the fungus ( and Nema-Q, an extract of the soap bark tree () for management of root-lesion () and ring ( nematodes on walnuts. In the first trial, spring and fall treatments of DiTera were applied each year for four years to variety 'Chandler' scion on seedling 'Paradox' rootstock, and to own-rooted 'Chandler' trees. On 'Paradox' rootstock, both DiTera and Nema-Q increased walnut yields ( ≤ 0.05) and produced more vigorous trees ( ≤ 0.05) without significant reductions in nematode populations ( ≤ 0.05). A second trial was conducted with three rates of DiTera and four rates of Nema-Q, combinations of the two products, and an untreated control on 'Chandler' scion on 'Paradox' rootstock. The highest rate of Nema-Q ( ≤ 0.05), and a combination treatment of DiTera plus Nema-Q ( ≤ 0.05) increased trunk circumference. Several treatments showed reductions in root-lesion and ring nematodes ( ≤ 0.05). Bionematicides can improve yield, growth, and vigor in walnut orchards infested with plant-parasitic nematodes.
PubMed: 33903856
DOI: 10.21307/jofnem-2021-044 -
American Journal of Physiology.... Jun 2021Donepezil is a centrally acting acetylcholinesterase (AChE) inhibitor with therapeutic potential in inflammatory diseases; however, the underlying autonomic and...
Donepezil is a centrally acting acetylcholinesterase (AChE) inhibitor with therapeutic potential in inflammatory diseases; however, the underlying autonomic and cholinergic mechanisms remain unclear. Here, we assessed effects of donepezil on mean arterial pressure (MAP), heart rate (HR), HR variability, and body temperature in conscious adult male C57BL/6 mice to investigate the autonomic pathways involved. Central versus peripheral cholinergic effects of donepezil were assessed using pharmacological approaches including comparison with the peripherally acting AChE inhibitor, neostigmine. Drug treatments included donepezil (2.5 or 5 mg/kg sc), neostigmine methyl sulfate (80 or 240 μg/kg ip), atropine sulfate (5 mg/kg ip), atropine methyl bromide (5 mg/kg ip), or saline. Donepezil, at 2.5 and 5 mg/kg, decreased HR by 36 ± 4% and 44 ± 3% compared with saline ( = 10, < 0.001). Donepezil, at 2.5 and 5 mg/kg, decreased temperature by 13 ± 2% and 22 ± 2% compared with saline ( = 6, < 0.001). Modest ( < 0.001) increases in MAP were observed with donepezil after peak bradycardia occurred. Atropine sulfate and atropine methyl bromide blocked bradycardic responses to donepezil, but only atropine sulfate attenuated hypothermia. The pressor response to donepezil was similar in mice coadministered atropine sulfate; however, coadministration of atropine methyl bromide potentiated the increase in MAP. Neostigmine did not alter HR or temperature, but did result in early increases in MAP. Despite the marked bradycardia, donepezil did not increase normalized high-frequency HR variability. We conclude that donepezil causes marked bradycardia and hypothermia in conscious mice via the activation of muscarinic receptors while concurrently increasing MAP via autonomic and cholinergic pathways that remain to be elucidated.
Topics: Animals; Atropine; Autonomic Nervous System; Blood Pressure; Cardiovascular System; Cholinergic Agents; Cholinesterase Inhibitors; Donepezil; Heart Rate; Mice; Mice, Inbred C57BL; Receptors, Muscarinic; Temperature
PubMed: 33851543
DOI: 10.1152/ajpregu.00360.2019 -
Journal of Nematology 2020The last decade has seen a sharp increase in nematicide research in the agricultural industry. As a result, several new synthetic nematicides have become available to...
The last decade has seen a sharp increase in nematicide research in the agricultural industry. As a result, several new synthetic nematicides have become available to growers, and several more are expected in the near future. This new interest in nematicides is directly related to the growing demand for safer and more selective products, and the increasing regulatory pressure on many of the traditional nematicides. This has led to a ban of several widely used fumigant (e.g. methyl bromide) and non-fumigant (e.g. aldicarb) nematicides. The loss of traditional nematicides, combined with a lack of replacement products and awareness of the damage that nematodes can cause, has not only raised concern among growers, but has also created new opportunities for the crop protection industry. Nematicides have become a priority, and many companies are now allocating significant research dollars to discover new nematicides. The new nematicides are very different from previous products: (i) they are more selective, often only targeting nematodes, and (ii) they are less toxic, and safer to use. This review article describes these new developments by discussing the challenges that are associated with finding new nematicides, reviewing the nature, characteristics, and efficacy of new nematicides, and discussing the impact they could have on future nematode management.
PubMed: 33829179
DOI: 10.21307/jofnem-2020-091