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The molluscicidal activity of six monoterpenes and two phenylpropenes against Theba pisana adults was evaluated using fumigation and direct contact methods. In the fumigant toxicity assay, (-)-citronellal showed the highest toxicity with LC50 value of 7.79 μl · l−1 air after 24 h of treatment, followed by (-)-terpinen-4-ol (LC50 = 12.06 μl · l−1), (-)-menthone (LC50 = 12.28 μl · l−1 air) and p-cymene (LC50 = 16.07 μl · l−1 air). Eugenol and trans-cinnamaldehyde were the most potent contact toxicants against T. pisana. Their LD50 values were 0.18 and 0.29 mg · snail−1 after 24 h of treatment, respectively. These two compounds were more toxic than a reference molluscicide, methomyl. In contrast, α-terpinene and (-)-citronellal were the least toxic compounds. In another experiment, the synergistic effect of piperonyl butoxide (PBO) on tested monoterpenes and phenylpropenes by topical application was examined. The results showed that the toxicity of the tested compounds was increased when mixed with PBO at a ratio [compound/PBO (1 : 2)] except for α-pinene and (-)-terpinen-4-ol in which the toxicity of binary mixtures was less than for single compounds. The synergistic effect of PBO improved with increased exposure time. The highest synergistic effect was observed with (-)-menthone and α-terpinene with synergistic ratios of 9.25 and 4.37, respectively. Monoterpenes and phenylpropenes and their mixtures with PBO described herein merit further studies as potential T. pisana control agents.

Fresh-market tomatoes are produced on a raised-bed plasticulture system that relies heavily on soil-applied preplant fumigants for the management of soilborne pathogens, nematodes, and weeds. Since the transition from methyl bromide to alternative fumigants, growers have experienced a resurgence of several soilborne pests and pathogens, including root-knot nematode caused by Meloidogyne spp. and Fusarium wilt caused by Fusarium oxysporum f. sp. lycopersici race 3. This resurgence is attributed to the inability of the alternative fumigants to effectively disperse through the soil in the same manner as methyl bromide. Two supplemental fumigation strategies, the application of chloropicrin (PIC) below bed edges (herein “supplemental PIC”) and broadcast deep-shank applications of 1,3-dichloropropene (1,3-D), were evaluated in conjunction with standard raised-bed applications of Pic-Clor 60, Pic-Clor 80, and Pic 100 covered with a virtually impermeable film or a totally impermeable film. Large-plot replicated studies were conducted in two separate commercial tomato fields with a history of production losses caused by root-knot nematode and Fusarium wilt. Deep-shank 1,3-D applications significantly reduced the recovery of root-knot and total parasitic nematodes across field sites before the preparation of raised beds. Both supplemental PIC and deep-shank 1,3-D reduced root-knot galling and Fusarium wilt incidence, but the latter supplemental treatment statistically had the greatest impact. Fumigant applied within raised beds or plastic film had no significant effect on root-knot galling or Fusarium wilt. Although both supplemental fumigation strategies had a significant effect on pest and disease pressure, neither statistically improved tomato yields based on small subplot harvests. Controlled laboratory experiments confirmed the fungicidal activity of 1,3-D against F. oxysporum f. sp. lycopersici, with 75, 90, 95, and 99% lethal doses corresponding to estimated field application rates of 56.1, 93.5, 121.6, and 184.7 liters/ha, respectively. The results demonstrate how fumigant placement can improve pest and disease control activity with current fumigant alternatives to methyl bromide and further support the broader pesticidal activity of some chemical fumigants.

This study investigated the effects of six crop rotation combinations on the soil quality of old apple orchard and seedling growth of Malus hupehensis Rehd. (apple rootstock) under pot conditions. The inhibitory effects of crops such as Allium fistulosum, Brassica juncea, and Triticum aestivum on four species of Fusarium were observed and compared in six treatments. These were continuous cropping (CK), fumigation with the methyl bromide (FM), rotating A. fistulosum only (R1), rotating A. fistulosum and T. aestivum (R2), rotating A. fistulosum, B. juncea, and T. aestivum (R3), and fallow (FC) in a year. The results showed that the biomass of Malus hupehensis Rehd. seedlings increased significantly. The root length increased and the root architecture was optimized. The respiration rate of the root system was increased by about 1 time after rotation. The treatments of R1, R2, R3, and FC increased bacterial count by 232.17%, 96.04%, 316.21%, and 60.02%, respectively. However, the fungi were reduced in varying degrees and bacteria/fungi ratio was increased by 5–10 times. The enzyme activities, pH, and organic matter were increased, but soil bulk density was decreased. Phenolic acids such as phloridzin was decreased significantly. The copy number of four Fusarium species declined by 85.59%, 74.94%, 69.68%, and 54.41% after rotating three different crops (R3 treatment). The root volatiles of three plants inhibited mycelial growth and spore germination of four Fusarium species.

Essential oil (EO) was hydrodistilled from Achillea biebersteinii and analyzed using gas chromatography–flame ionization detection (GC–FID) and (GC–MS). Three monoterpenes, α-terpinene, p-cymene, and camphor were isolated as the main terpenes in the EO. Oil-in-water nanoemulsion (particle size 52.7 ± 4.4 nm) was prepared and characterized from EO through a hydrothermal approach. The EO products caused insecticidal effects and altered F1 progeny of the red flour beetle, Tribolium castaneum (Herbst) in a dose and exposure time-dependent manner. The nanoemulsion was superior in bioactivity, followed EO. At 12.5 µl/cm2, nanoemulsion and EO caused 100% mortality of the second larvae after 4 days of exposure with reduction of F1 progeny of 100.0 and 89.2%, respectively. At 50.0 µl/cm2, percentage mortality and reduction in progeny of EO products ranged between (61.4–100%) and (53.0–100%), respectively. Upon fumigation, nanoemulsion at 10 µl/L air caused 100% mortality of the second larvae after 4 days of exposure. At 20 µl/L air and 4 days after treatment, percentage mortality with the remainder botanicals ranging between 64.7 and 100. LC50′s of products after 48 h exposure ranging between 6.7 and 58.1 µg/cm2 in insecticidal bioassay, and between 3.6 and 26.3 µl/L upon fumigation. Botanicals caused a remarkable inhibition of acetylcholinesterase activity (AChE), where nanoemulsion (IC50 = 14.22 mM), EO (IC50 = 35.12 mM) and camphor (IC50 = 23.93 mM) were superior as AChE inhibitors. There is a potential for using of A. biebersteinii EO, its nanoemulsion and monoterpenes as natural grain protectants after the required toxicological investigations.

The interception of exotic ants and termites from stone and lumber imported into Korea is on the rise, including Solenopsis invicta. Currently, a relatively long exposure (24 h) of methyl bromide (MB) fumigation is the only practical disinfestation option for exotic ants and termites on imported stone and lumber. In this study, ethyl formate (EF) wase evaluated as a potential MB alternative to disinfest ants and termites in imported lumber, with a focus on S. invicta. As S. invicta is not established in Korea, we first determined whether Reticulitermes speratus, established in Korea, could be considered as an EF surrogate of S. invicta. From 1 h EF fumigation trials, workers of S. invicta were more sensitive to EF than those of R. speratus based on lethal concentration × time causing 99% mortality (LCt99%), supporting that R. speratus can be used as an EF surrogate of S. invicta. When R. speratus workers were further fumigated with EF for 4 h at four different temperatures, LCt99% values for R. speratus workers were 108.00, 63.31, 77.24, and 67.24 g h/m3 at 2, 5, 13, and 23 °C, respectively. From scale-up (0.65 m3) and commercial scale (76.4 m3) trials containing two infestation-prone lumber species, lauan (Shorea spp.) and acacia (Acacia spp.), 140 g/m3 EF at >5 °C for 4 h resulted in the complete control of R. speratus workers, suggesting that 140 g/m3 4 h-EF-fumigation may be applicable as a potential MB-alternative treatment for disinfestation of invasive S. invicta on imported lumber.

Background The house mosquito, Culex pipiens L. is a harmful species, widespread in urban areas, and considered the primary enzootic vector of West Nile arbovirus. Widespread insecticide resistance in mosquito populations and the environmental risks and toxicity hazards of chemical pesticides make insecticides an inadequate mosquito control strategy. Seeking ecofriendly tools for mosquito control tools has become necessary. Results Essential oil (EO) was hydrodistilled from the fruits of Brazilian pepper, Schinus terebinthifolius Raddi and analyzed using gas chromatography-flame ionization detection and gas chromatography-mass spectrometry. An oil-in-water nanoemulsion (particle size 41.3 nm) was developed and characterized from EO using a green low-energy approach. EO, its nanoemulsion and monoterpenes showed mosquitocidal, repellent and acetylcholinesterase inhibitory activities against Cx. pipiens. A nanoemulsion concentration of 30 μl L-1 caused 100% larval mortality after 24 h of exposure, whereas EO, d-limonene and α-phellandrene at 60 μl L-1 caused 100%, 92.4% and 88.2% larval mortality, respectively. The concentration that killed 50% of organisms (LC50 ) for larvae after 24 h ranged between 6.8 and 40.6 μl L-1 . Upon fumigation, 15.0 μl L-1 of nanoemulsion killed 94.5% of adults after 24 h of exposure. LC50 values against adults ranged between 5.3 and 31.2 μl L-1 . EO products exhibited repellence activity at concentrations between 0.5 and 4.0 μl cm-2 . Test materials effectively inhibited the acetylcholinesterase activity of mosquito and were safe toward the non-target organisms Gambusia affinis and Eisenia fetida. Conclusion There is a potential for using S. terebinthifolius EO, its nanoemulsion and monoterpenes as ecofriendly natural mosquitocides.

BACKGROUND Sitophilus zeamais is one of the most economically impactful pests, attacking various grains and processed foods. Control of this insect has been achieved using synthetic insecticides, exacerbated and careless use of which has led to the development of resistant insect populations, toxicity to non-target organisms and environmental contamination. In this study, Piper corcovadensis leaf essential oil (PcLEO) and its major compound, 1-butyl-3,4-methylenedioxybenzene (BMDB), were investigated as alternative insecticidal agents against S. zeamais. RESULTS Characterization of PcLEO showed the presence of 40 compounds. The major components were the phenylpropanoid BMDB (35.77%) and the monoterpenes α-pinene (14.95%) and terpinolene (6.23%). PcLEO and BMDB were toxic by fumigation (half-maximal lethal concentration [LC50 ]: 9.46 and 0.85 μl L-1 of air, respectively), by contact (half-maximal lethal dose [LD50 ]: 9.38 and 6.16 μg g-1 of insect, respectively) and ingestion (LC50 : 16.04 and 14.30 mg g-1 , respectively). In the ingestion test, both PcLEO and BMDB promoted the loss of insect biomass and had a strong deterrent effect. In addition, both were able to inhibit trypsin and α-amylase activities. CONCLUSION PcLEO and BMDB exhibited insecticidal activity against S. zeamais, with a toxic effect by fumigation, contact and ingestion, in addition to food deterrence and inhibiting trypsin and α-amylase activities, suggesting their potential for use in the control of this pest.

Black spot disease caused by Ceratocystis fimbriata is destructive to the production, transportation, and storage of sweet potato. The antifungal effects of Bacillus tequilensis XK29 against C. fimbriata through volatile organic compounds (VOCs) were evaluated in this study. The activated carbon assay proved that XK29 could exert antibiotic effects through volatiles. By optimizing the wheat seed weight, inoculation method, concentration, volume, and time, the antifungal activity of XK29 was significantly improved. XK29 fumigation inhibited spore formation and germination and changed the cell morphology of C. fimbriata. During the storage of sweet potato tuber roots, XK29 effectively controlled black spot disease and reduced the weight loss and malondialdehyde content. Metabolomic analysis revealed that 21 volatile compounds were released from XK29. Isovaleric acid, isobutyric acid, and 2-methylbutanoic acid effectively inhibited the growth of C. fimbriata. These results indicate that B. tequilensis XK29 has a good potential to be developed as a microbial fumigation agent.

Ethyl formate (EF) was evaluated as a potential alternative to methyl bromide (MB) for phytosanitary treatment of imported citrus fruit in the Republic of Korea. Planococcus citri (Risso) (Hemiptera: Pseudococcidae), a mealybug with known tolerance against EF and MB, was used as a representative pest to test efficacy of the two fumigants against eggs. In nine commercial-scale refrigerated container (67.5 m3) trials using imported orange, lemon and grapefruit, EF applied at the currently approved dose for citrus (70 g·m-3 at 5°C for 4 h, developed for Aspidiotus excisus Green (Hemiptera: Diaspididae), a species less EF tolerant than P. citri) resulted in 76.9–98.3% mortality of P. citri eggs. The EF treatment did not affect the sugar content or the color of peel and pulp of the treated fruit. When oranges were treated according to the current MB (64 g·m-3 at >5°C for 2 h) or EF treatment guidelines, the concentration of fumigant around the fruit fluctuated between 9.4 and 185.1 ppm for EF and 9.5–203.0 ppm for MB during the 72-h post-fumigation processes (venting [0–2 h], transportation to storage [2–24 h], and storage periods [24–72 h]) with both EF and MB maintained between 10 and 100 ppm during the storage period. Considering the efficacy of EF, its apparent lack of phytotoxicity, and its more manageable threshold limit value for humans (100 ppm EF compared to 1 ppm MB for an 8-h time weighted average exposure), our results suggest that EF may be a promising alternative to MB for the phytosanitary treatment of imported citrus in Korea.

Fumigation of fruits and vegetables during quarantine and pre-shipment (QPS) treatment should be effective with a shorter fumigation time to minimize phytotoxicity. In this research study, a shorter fumigation time, 2 hours exposure which is shorter than that of the current commercial fumigation procedures using a lower dose of ethyl formate (EF) mixed with phosphine (PH3) on strawberry was investigated. The reciprocal effect between EF and PH3 against nymphs and adult Myzus persicae (Sulzer) and Tetranychus urticae (Koch) was evaluated. In addition, L(Ct)50 and L(Ct)99 of EF only and EF mixed with PH3 were analyzed at 5°C and 20°C. The synergistic ratio (SR) of L(Ct)50 and L(Ct)99 for the nymph and adult stages of M. persicae were >1.0, which indicated a synergistic effect between EF and PH3. However, the SR values of L(Ct)50 and L(Ct)99 of the nymph and adult stages of T. urticae were ≤1.0 indicating that there was no synergistic effect between the two fumigants against T. urticae. Our results showed that the reciprocal effect between EF and PH3 has different effects on M. persicae and T. urticae. This could be attributed to the biological and physical differences between the class Arachnida and Insecta. The synergistic effect between EF and PH3 against M. persicae within a shorter exposure period and without phytotoxicity on fruits and vegetables will significantly benefit the horticultural industry.

The use of wood for the timber industry increases, but wood with a high natural durability class, especially class I & II was limited. Efforts to improve the quality of wood are needed. The research purposed to increase the durability of Medang wood (Chinnamomum javanicum) with the preservation methods using fumigation and evaluated against Schizophyllum commune Fries fungi. Medang wood from gubal area was achieved from Kubu Raya Regency and made into a sample for preservation treatment measuring 5 cm x 2 cm x 2 cm. The wood preservation methods used fumigation. The fumigation process used an oven and time of fumigation consisting of 12 hours, 24 hours, and 36 hours. The temperature process was 80oC. After preservation, the wood was tested against Schizophyllum commune Fries based on SNI 7207-2014. The result of preservation showed that the fumigation process changed the color of Medang wood. The color changed from white pale into brown (12 hours fumigation), dark brown (24 hours fumigation), and very dark brown (36 hours fumigation). The weight loss of Medang wood after 12 weeks attacked by Schizophyllum commune Fries fungi was range between 2.45% - 3.44%. The weight loss of Medang wood on treatment 12 hours fumigation was 3.44%, on treatment 24 hours was 3.34% and on the treatment of 36 hours was 2.45%. After the fumigation methods, the durability of Medang wood increased into II class. The compound from smoke during the fumigation process, which functions as antifungi, was phenol. The optimum treatment to increase the durability of Medang wood was fumigation for 36 hours with a temperature of 80oC.

Vascular wilt diseases caused by Verticillium dahliae Kleb. are difficult to control and lead to increasing losses of many crops worldwide. It can cause disease on not only horticultural crops but also many economically important crops such vegetables, legumes, forest trees, woody and herbaceous plants. Reasons of this situation are various: (i) the specialization of crop production resulted in the accumulation of the pathogen in the soil, especially monoculture production; (ii) the lack of an efficient and safe soil fumigation method; (iii) the production in large amounts of survival structures—microslerotia and melanized hyphae that are resistant to chemical and biological degradation.Due to the lack of effective synthetic agents for eradication of V. dahliae from soil, considerable interest in this paper has been focused on biological control, especially the selection of microorganisms with mycoparasitic activity towards V. dahliae microsclerotia, that can decrease their number in soil. The main attention is paid on the Trichoderma fungi, non pathogenic Fusarium spp., Talaromyces flavus and bacteria Bacillus spp., Pseudomonas spp. and Streptomyces spp. that are discussed in this review. In this work the suppressive effect of organic amendments against this soil-borne pathogen is also mentioned. In addition biofumigation using toxic plant materials, which is an approach to the soil-borne pathogen management could be an effective method to control diseases caused by V. dahliae.

Aspergillus flavus is a frequent contaminant of maize grain. We isolated this fungus, determined the colony morphology and species (by internal transcribed spacer sequencing) and measured the aflatoxin content. The selected A. flavus fungi were placed into two groups, toxigenic and atoxigenic; both appeared similar morphologically, except that the atoxigenic group lacked sclerotia. An essential oil fumigation test with clove and cinnamon oils as antifungal products was performed on fungal conidial discs and fungal colonies in Petri plates. Cinnamon oil at 2.5 to 5.0 μL/plate markedly inhibited the mycelial growth from conidial discs of both strains, whereas clove oil showed less activity. The oils had different effects on fungal mycelia. The higher clove fumigation doses of 10.0 to 20.0 μL/plate controlled fungal growth, while cinnamon oil caused less inhibition. Compared with atoxigenic groups, toxigenic A. flavus responded stably. Within abnormal A. flavus hyphae, the essential oils degenerated the hyphal morphology, resulting in exfoliated flakes and shrinkage, which were related to fungal membrane injury and collapse of vacuoles and phialide. The treatments, especially those with cinnamon oil, increased the electroconductivity, which suggested a weak mycelium membrane structure. Moreover, the treatments with essential oils reduced the ergosterol content in mycelia and the aflatoxin accumulation in the culture broth. The fumigations with clove and cinnamon oils inhibited the development of both conidia and colonies of A. flavus in dose-dependent manners.

Background To improve the utilization rate of cinnamon essential oil and compensate for the shortcomings of its easy decomposition and oxidation, the microemulsion of cinnamon essential oil was prepared using Tween 80 and anhydrous ethanol as surfactant and cosurfactant, respectively. The effects of the surfactant type, Km value, preparation temperature and aqueous pH on the quality of the microemulsion were studied via a pseudo-ternary phase diagram. The slow-release performance of cinnamon essential oil microemulsion and the control performance of the insect repellent package on the rice weevil were characterized. Results The results showed that, when Tween 80 was used as a surfactant and anhydrous ethanol was used as a cosurfactant, the Km value was 3:1, preparation temperature was 40 °C, aqueous pH was 5 and prepared cinnamon essential oil microemulsion was of the O/W type. The microemulsion had strong stability and a 81.5-nm concentrated particle size distribution, and possessed excellent embedding and sustained-release effects. The prepared insect repellent active package prolongs the use time and the effect of cinnamon essential oil. The repellent rate of the rice weevil was as high as 100% after 48 h, and the contact mortality and fumigation mortality rates of the rice weevil also reached 96.67% and 86.67%, respectively, after 96 h. Conclusion The prepared cinnamon essential oil microemulsion and active packaging had a good sustained-release effect. © 2021 Society of Chemical Industry.

Increased plant phosphorus uptake and growth as a result of inoculation with arbuscular mycorrhizal (AM) fungi is observed less often under field conditions than in pot experiments. Interaction between introduced and indigenous AM fungi is one of the reasons for ineffectiveness of inoculation in the field. We aimed to distinguish the effect of introduced and indigenous AM fungi on phosphorus uptake and growth of Allium fistulosum in a field experiment. Superphosphate was applied in the ratio of 0 or 317 P kg ha−1 to the plots fumigated with or without dazomet that is a common soil fumigant. Seedlings of A. fistulosum that had been inoculated with or without Rhizophagus spp. strain R-10 were transplanted into the plots. AM fungal colonization, OTU read abundance of indigenous and introduced AM fungi, shoot P concentration, and shoot growth were measured at 31, 60, 90, and 131 days after transplanting (DAT). We could partially separate the effects of introduced AM fungi from indigenous AM fungi by fumigation with dazomet. Though neither inoculation nor P level affected shoot fresh weight and shoot P content in the non-fumigated main plot at 131 DAT, significantly higher shoot fresh weight was obtained by the inoculation with no P fertilizer in the fumigated main plot at this final sampling stage. These results indicate that the colonization of roots by introduced AM fungi is affected by the abundance of indigenous AM fungi and this interaction determines growth response of host plants under field conditions.

BACKGROUND Methyl bromide is an ozone depleting substance and is still being used for quarantine treatment of wood products and logs. Ethanedinitrile (C2 N2 ) is a new potential alternative fumigant and has been investigated as a timber fumigant because it has shown better penetration through timber and responds fast to insects and nematodes. This article reports on laboratory and commercial-scale trials with C2 N2 for important wood destroying pests namely Tomicus piniperda (Pine bark beetle) adults, Hyphantria cunea (Fall webworm) lavae, Reticulitermes speratus (Japanese Termite) adults and Cryphalus fulvus (Scolytidae) (Yellow minute bark beetle) which naturally infests pine logs. RESULTS Tomicus pi:niperda adults were more tolerance than H. cunea lavae and R. speratus adults with lethal concentration × time affecting 99% mortality (LCt99 ) values of 27.84, 7.49 and 3.30 g h m-3 , respectively. Ethanedinitrile shows exceptionally high toxicity to adult R. speratus which was almost 26 times more toxic than methyl bromide. The complete control of larvae and adults stages of C. fulvus was achieved at concentration × time (Ct) products from 89.6 g h m-3 in a 6-8 L fumigation chamber. Temperature-depending trials on C. fulvus were conducted with C2 N2 doses of 30 at 21 ± 6 and 40 g m-3 at 9 ± 3 and 2 ± 2 °C for 24 h. The Ct products of 182.2, 227.8 and 268.6 g h m-3 were obtained and C. fulvus was completely controlled at all tested temperatures. CONCLUSION Ethanedinitrile could offer quarantine treatment for wood products and logs for the control of wood destroying insect pests and termites.

This study aimed to investigate the effects of the essential oils of Cymbopogon flexuosus and Alpinia zerumbet in the treatment of cowpea [Vigna unguiculata (L.) Walp.] grains under storage conditions for the management of Callosobruchus maculatus. Measurements of the effects of these essential oils were based on contact, fumigation, and repellency tests. The lethal concentrations (LC50) obtained from the contact tests were 0.65 and 11.23 µL/20 g for the essential oils of C. flexuosus and A. zerumbet, respectively. The impact on F1 offspring increased with increasing concentrations of essential oils. The LC50 values obtained from the fumigation tests were 2.34 and 8.69 µL/L of air for the C. flexuosus and A. zerumbet, respectively. Regarding repellency, both essential oils were classified as neutral. C. flexuosus was more toxic than A. zerumbet in the contact test; however, there was no difference in their toxicities found in the fumigation test. The essential oils of C. flexuosus and A. zerumbet presented a great insecticidal potential against C. maculatus, therefore, can be an environmentally sustainable alternative to synthetic chemical fumigants.

Zingiber cassumunar is an important plant used in traditional medicine and as a natural mosquito repellent. However, the compounds responsible for the repellent activity of the plant are still unknown. The aim of the study is to identify the components of Z. cassumunar essential oil that show repellent activity against Aedes albopictus. We also evaluated the larvicidal and adulticidal activities of Z. cassumunar essential oil against Ae. albopictus. In-cage mosquito repellent experiments showed that Z. cassumunar essential oil possessed moderate repellent activity with a minimum effective dose (MED) of 0.16 ± 0.01 mg/cm2, compared to reference standard N,N-diethyl-3-methylbenzamide (DEET, 0.03 ± 0.01 mg/cm2). Bioassay-guided fractionation identified the major active compound of Z. cassumunar essential oil as (−)-terpinen-4-ol (1) (MED: 0.19 ± 0 mg/cm2). We also found that Z. cassumunar essential oil showed moderate larvicidal activity against first instar larvae of Ae. albopictus with a LC50 (50% lethal concentration) of 44.9 μg/L after 24 h. Fumigation bioassays showed that Z. cassumunar essential oil exhibits moderate adulticidal activity against Ae. albopictus with a LC50 of 5.44%, while (−)-terpinen-4-ol showed significant adulticidal activity with a LC50 of 2.10% after 24 h. This study verifies that the Z. cassumunar essential oil has mosquito repellent activity, and that (−)-terpinen-4-ol is mainly responsible for this activity. Furthermore, this study provides scientific support for the folk usage of Z. cassumunar essential oil as mosquito repellent and indicates that Z. cassumunar essential oil and (−)-terpinen-4-ol can be used as plant-derived repellents and insecticides for mosquito control.

In North America, potato early dying is often controlled using soil fumigants. Fumigants confer benefits on plant health but also impact soil microbial activity, including nitrogen (N) cycling. The purpose of this study was to evaluate the effects of two soil fumigants, chloropicrin and metam sodium, on potato crop yield, N uptake, and N use efficiency (NUE), as well as soilborne pathogens, soil microbial respiration rates and soil concentrations of NH4+-N and NO3−-N. We established a field study with a split-plot randomized complete block design in 2016 and 2017, with whole plots divided among three fumigation treatments (no fumigant, chloropicrin, or metam sodium) and split into five subplots, each receiving a different total application rate of N (45, 135, 202, 269, or 336 kg·ha−1 N). Both fumigants suppressed Verticillium dahliae propagule concentrations and foliar symptoms of potato early dying while increasing yield, final tuber set, N uptake, and NUE. Fumigation did not affect the agronomic optimum N rate, nor the response of marketable yield to N rate, but it did increase yield per unit N applied (partial factor productivity) by 16% and 35% over the non-fumigated controls in 2016 and 2017, respectively. Chloropicrin, but not metam sodium, reduced the prevalence of common scab symptoms in tubers. Both fumigants decreased microbial respiration rates before planting and at midseason. Fumigants reduced nitrification rates before planting and at midseason, with chloropicrin having a particularly strong effect before planting. While fumigation conferred benefits to yield and NUE, its effects on microbial community structure and function merit further study.

The objectives of this study were to evaluate the toxicity of ozone on Zabrotes subfasciatus (Boheman, 1833) in lima bean seeds, determine the instantaneous population growth rate (ri) of these ins...

The antifungal activity of volatile organic compounds (VOCs) from 10 Streptomyces isolates was tested using the double-dish chamber method. The VOCs-producing strain S97 exhibited the highest inhib...

The use of shipping containers for cargo transportation has the potential to transport insect pests from infested to non-infested areas. Fumigation is required as an appropriate biosecurity measure to exterminate insect pests. Fumigation trials were conducted in a 20 ft general purpose (GP) shipping container. Four species of mixed-age cultures, Lasioderma serricorne (F.), Sitophilus oryzae (L.), Trogoderma variabile (Ballion), and Rhyzopertha dominica (F.) were used for bioassays. Ninety g m-3 of ethyl formate + nitrogen formed non-flammable ethyl formate fumigant formulation was released into the container. The fumigation yielded sufficient concentration × time (Ct) products at a range of 437.54-449.19 g h m-3 in the container for exterminating all life stages. Ethyl formate left no residue in treated drinks. This study demonstrated that on site generation of a non-flammable ethyl formate and nitrogen fumigant can be achieved and this new application technology ensures that ethyl formate distributes evenly in the container within 30 min after application and with a variation of

Preventive measures based in the control of insect vectors are considered as the best choice to decrease the incidence of insect-borne diseases. Herein we report on the volatile content of the leaf essential oils from Marina neglecta, a medicinal plant distributed in the tropical regions of southern Mexico. In order to investigate the chemical variation of the essential oils, a volatile screening was performed during the four seasons of the years 2016–2019. Simultaneously, their biological activity was tested on distinct life stages of Meccus pallidipennis, M. bassolsae, Aedes aegypti and A. albopictus. Essential oils were mainly constituted of β-pinene (>30%) β-caryophyllene (>25%) and germacrene D (>13%). Dorsal-abdomen application of essential oils on triatomines, revealed an efficient LC50 for nymphs of the stages I to III (4 µg/insect), nymphs of the stages IV to V (5–6 µg/insect), and adults (7–8 µg/insect). The LT50 for the stages I to III was between 6 and 8 h, whereas that for the stages IV to V and adults oscillated between 12 and 16 h and 22 to 26 h, respectively. Fumigation experiments performed on nymph V, demonstrated that 300 µg L−1 air produced 100% mortality after 72 h post-treatment. Among tested volatiles, β-pinene and β-caryophyllene produced a comparable mortality rate (p

Fusarium wilt is a devastating disease which impacts watermelon production. Soil fumigation using dazomet followed by biological organic fertilizer was applied to suppress the Fusarium wilt disease. We propose that fumigation suppresses the soil indigenous community, especially the soil-borne pathogens, while the utilization of bio-organic fertilizer facilitates the recovery of the soil microbiome to a beneficial, suppressive state through the introduction of plant growth-promoting microorganisms. Greenhouse experiment showed that applied biological organic fertilizer after dazomet fumigation effective restrain the disease incidence with a 93.6% disease control. Fumigation strongly decreased soil microbial diversity and altered relative taxa abundances, suggesting the possibility of niche release by the resident soil microbial community. Fumigation followed by bio-fertilizer transformed the soil microbial community composition and resulted in higher relative abundances of beneficial microbial groups such as Bacillus (8.5%) and Trichoderma (13.5%), coupled with lower Fusarium abundance compared to other treatments. Network analysis illustrated that soil fumigation decreased interactions within the soil microbial community with less nodes and links while bio-fertilizer addition promoted node interactions. In addition, bio-fertilizer addition after fumigation resulted in the beneficial species becoming the key network connectors. Collectively, fumigation appears to release the resident soil niche resulting in lower diversity while the beneficial microbes introduced by bio-fertilizer addition colonize these niches, leading to a more complex community with fewer pathogens that suppresses Fusarium wilt disease incidence.

BACKGROUND Managing resistance to phosphine (PH3) in rusty grain beetle, Cryptolestes ferrugineus, is challenging, as strongly resistant insects of this species require very high concentrations over lengthy exposure periods (>10 days). Recently, approaches that enhance the efficacy of PH3 have gained momentum to control this pest, especially co-fumigations. In this study, efficacy of co-fumigating PH3 with another commercially available fumigant, sulfuryl fluoride (SF), has been evaluated against adults and eggs of two PH3-resistant strains of C. ferrugineus. Concentrations of the mixture, representing lower than current application rates of both fumigants, were tested towards its field use. RESULTS Co-fumigation of PH3 with SF was achieved in two patterns: over a continuous exposure period of 168 h simultaneously and sequentially over two periods of 78 h, in which insects were exposed to SF first followed by PH3 with 12 h aeration in-between. Results of simultaneous fumigations identified two effective co-fumigation rates, SF 185 + PH3 168 g hm−3 and SF 370 + PH3 84 g hm−3 that yielded complete control of adults and eggs. These two rates also were equally effective when they were applied sequentially and produced consistent results. Irrespective of application methods, concentrations of both PH3 and SF failed individually in achieving complete mortality of either adults or eggs or both. CONCLUSION Our results confirmed that a co-fumigation strategy involving half the current standard rate of PH3 (84 g hm−3) with one-fourth of the current maximal registered rate of SF (370 g hm−3) can provide effective control of strongly PH3-resistant C. ferrugineus.

Sulfur fumigation is adopted in the post-harvest processing of herbal drugs. In addition to the sulfur dioxide residual, sulfur fumigation could also lead to chemical transformations of native compounds in the herbs to generate sulfur-containing derivatives. In this study, influence of sulfur fumigation on the chemical composition of Farfarae Flos (FF) was investigated by the ultra-high-performance liquid chromatography-Q exactive hybrid quadrupole-orbitrap high-resolution accurate mass spectrometry (UHPLC-Q-orbitrap HRMS). In addition to 103 native compounds in FF, 12 sulfur-containing caffeoylquinic acids were also detected after sulfur fumigation. The further screening results showed that the diagnostic sulfate/sulfite derivatives were effective for rapid discrimination of sulfur-fumigated FF samples. In brief, sulfur fumigation can induce chemical transformations of phenylpropanoids, and the corresponding sulfur-containing derivatives could be regarded as the characteristic chemical markers of sulfur-fumigated FF.

Balmumu güvesi, Tunus'taki arıcılar için çok fazla zarara ve kayba neden olan bal arısı zararlılarından biridir. Balmumu ve balı kirlettikleri bilinmesine rağmen böcek öldürücülerin kullanımı giderek daha fazla kullanılmaktadır. Bu çalışmada, iki Kuzey Afrika ortak bitkisi Thymbra capitata L. ve Mentha pulegium L.'nin büyük mum güvesi (GWM) G. mellonella üzerine etkisinin araştırılması amaçlanmıştır. Ayrıca büyük balmumu güvesinin gelişme aşamalarının sürelerini de belirlenmiştir. Sonuçlar, 30 ila 33°C arasında değişen bir sıcaklık altında, yumurtalardan GWM'li yetişkinlere kadar olan toplam sürenin 51 gün sürdüğünü göstermiştir. Fumigant testi, test edilen larva dönemlerinde her iki yağın da toksisitesini göstermiştir. İkinci larva dönemi, 4. evreye göre daha hassastır. Dahası, M. pulegium, 2. larva dönemine karşı, sırasıyla, 48. saatte 41.829 ve 456.276 µl / Lair'de bir LC50 ile T. capitata'dan daha toksik olduğu belirlenmiştir. Bu bulgulara göre uçucu yağlar, mum güvelerini kontrol altına almak için böcek ilaçlarına iyi bir alternatif sunmaktadır., The wax moth is one of the honeybee pests that cause a lot of damage and loss for the beekeepers in Tunisia. The use of insecticides is more and more used although they are known to contaminate wax and honey. This study aims to test the essential oils of two North African common plants Thymbra capitata L. and Mentha pulegium L. efficacy as alternative method by fumigation on instars of Galleria mellonela L. We also determined the duration of the development stages of the great wax moth (GWM) presented in Tunisia. Results showed that under a temperature ranged between 30 and 33°C, the total duration from eggs to adults of GWM lasted 51 days. The fumigant test showed the toxicity of both oils on larvae instars tested. The second larvae instar was more susceptible than the 4th instar. Moreover, M. pulegium was more toxic against the 2nd larvae instar than T. capitata with an LC50 at 48h of 41.82 and 456.27 µl/L air, respectively. The essential oils present a good alternative to the insecticides to control wax moths.

Trogoderma granarium Everts (Coleoptera: Dermestidae) is one of the most important quarantine pests of stored grains. Control of this insect species can be achieved through a gaseous insecticide, phosphine. Many studies focus on the effect of phosphine on different developmental stages of insects, with most of them highlighting eggs as the most tolerant stage. Our data showed that 2-d-old eggs of T. granarium are more susceptible than 1-d-old eggs. Faster hatching was observed in eggs exposed to phosphine for 2 d compared to controls and the result was more pronounced for 1-d-old than 2-d-old eggs. In contrast to the 2-d exposure, hatching rates of eggs exposed to 4 and 6 d were notably reduced, while there was a delay in egg hatching compared to controls. Moreover, larval development from untreated eggs was faster than the larvae from treated eggs, regardless of the exposure time. These dissimilar patters in larval growth may suggest certain delayed effects of phosphine fumigation. The results of the present work can be further utilized for the development of phosphine-based quarantine and pre-shipment treatments for the control of T. granarium.

Cowpea (Vigna unguiculata) is an important crop as a source of basic protein for populations in tropical countries, generating profit after the processing and storage of grains. However, the attack of pests such as cowpea weevil Callosobruchus maculatus (Coleoptera: Chrysomelidae: Bruchinae) can limit the production of cowpea, with the insect causing qualitative and quantitative losses to the grains. Its control is commonly performed with fumigant phosphine, which due to its almost exclusive use, has selected resistant populations of insects, causing control failure. This way, the present research aimed to investigate the effects of essential oils of Betula lenta, Cinnamomum cassia, Citrus aurantium var. Amara and Acorus calamus in the treatment of cowpea grains [Vigna unguiculata (L.) Walp.] under storage conditions, for the management of Callosobruchus maculatus. The effects of essential oils were investigated through contact, fumigation, and repellency tests. The LC50 found in the test of contact was 0.61; 0.63; 0.64 and 22.98 μL/20 g of beans for the oils of A. calamus, B. lenta, C. cassia, and C. auratium var. Amara, respectively. Based on the data, the number of eggs and insects that emerged decreased as the concentration of essential oils increased. The LC50 values in the fumigation test were estimated at 5.16; 8.24; 25.84 and 35.31 μL/L of air for A oils. calamus, B. lenta, C. auratium var. Amara and C. cassia, respectively. In the repellency test, all oils acted like antagonists to C. maculatus biology, but the latter presented deterrence against the oviposition and the emergence of adults in most concentrations. These findings indicate that essential oils can be used to manage C. maculatus.

Plant parasitic nematodes cause significant yield reductions worldwide. Before development of soil fumigation, sustainable practices were developed for nematode management; but were utilized with limited success. The restricted availability of fumigants and other nematicides, has stimulated a return to research into more sustainable management scenarios. In recent years, new tools have been developed that improve the successful utilization of sustainable methods including: nematode resistant crop varieties, trap cropping, biofumigation, molecular identification techniques, databases that can be accessed online to search for crops resistant to nematodes, relatively inexpensive soil temperature dataloggers, nematode degree-day models, research on nematode biology and population cycling, development of less toxic chemicals, and development of new soil amendments and natural products. Combining these with a strong nematode control and certification program for nursery crops, have made it possible to develop promising scenarios to reduce damaging nematode populations and increase yields.

BACKGROUND The rice weevil, Sitophilus oryzae (L., 1763) (Coleoptera: Curculionidae), is a stored grain/seed pest of several crops. Botanicals represent an option to manage this pest, especially those with high toxicity determined by its structure and physicochemical properties and low residue left behind on treated grains/seeds. Enantiomers are bioactive molecules in organic processes. The aim of this study was to evaluate the insecticidal activity of two enantiomeric forms of the monoterpenes citronellal, limonene, linalool, menthone and α-pinene against S. oryzae adults through contact, fumigant and repellent assays. RESULTS All results were compared with absolute acetone as the negative control and those from contact assays also with malathion as the positive control. (S)-(-)-linalool was the most toxic by contact to S. oryzae and (S)-(-)-menthone through fumigation, while the two enantiomeric forms of menthone and α-pinene were the best repellents. CONCLUSIONS The high toxicity of only one of the two monoterpene enantiomers showed the importance of form and percentage of enantiomer in the commercial product, which affect the success of the product to controlling S. oryzae. © 2021 Society of Chemical Industry.

BACKGROUND Two Fusarium fungi, F. oxysporum and F. proliferatum, have been recognized as major pathogenic fungi that cause postharvest decay of chili fruits. Ozone and some toxic chemicals are used to control pathogenic infections, leading to longer storage lives of agricultural commodities. However, these chemicals may pose some risks to the applicators and the environment. Therefore, alternative, easy-to-use fumigants for effective control of Fusarium infections in harvested fresh chilies are needed. RESULTS Two endophytic fungi, Trichoderma afroharzianum strain MFLUCC19-0090 and T. afroharzianum strain MFLUCC19-0091, were isolated from Schefflera leucantha leaves. Their volatile compounds were investigated for antifungal activities against F. oxysporum and F. proliferatum. In vitro results showed that the volatile compounds produced by each strain inhibited pathogen growth. Additionally, the Trichoderma-derived volatile compounds significantly reduced Fusarium-related disease severity and incidence percentages in the inoculated fresh chilies. Antifungal properties of the volatile compounds were found to be specific to the species of the tested pathogens (MFLUCC19-0090 greatly suppressed F. oxysporum and MFLUCC19-0091 greatly suppressed F. proliferatum). Seventy-three volatile compounds were detected from both strains. Among the major volatile compounds detected, phenyl ethyl alcohol was found to possess the strongest antifungal activity against both pathogens. CONCLUSION These Trichoderma-derived volatile compounds may be used as alternative fumigants for controlling Fusarium rot in harvested fresh chilies. The successful use of volatile compounds as biofumigants can prevent significant market losses and, more importantly, may reduce the health hazards caused by Fusarium-associated mycotoxin exposures among consumers. © 2021 Society of Chemical Industry.

Bacillus cereus strain Bc-cm103 shows nematicidal activity and, therefore, has been used as a biological control agent to control the root-knot nematode Meloidogyne incognita. However, it remains unknown whether volatile organic compounds (VOCs) produced by B. cereus strain Bc-cm103 are effective in biocontrol against M. incognita. Therefore, in this study, we investigated the activity of Bc-cm103 VOCs against M. incognita. The B. cereus strain Bc-cm103 significantly repelled the second-stage juveniles (J2s) of M. incognita. In vitro evaluation of VOCs produced by the fermentation of Bc-cm103 in a three-compartment Petri dish revealed the mortality rates of M. incognita J2s as 90.8% at 24 h and 97.2% at 48 h. Additionally, evaluation of the ability of Bc-cm103 VOCs to suppress M. incognita infection in a double-layered pot test showed that root galls on cucumber roots decreased by 46.1%. Furthermore, 21 VOCs were identified from strain Bc-cm103 by solid-phase microextraction gas chromatography–mass spectrometry, including alkanes, alkenes, esters, and sulfides. Among them, dimethyl disulfide (30.63%) and S-methyl ester butanethioic acid (30.29%) were reported to have strong nematicidal activity. Together, these results suggest that B. cereus strain Bc-cm103 exhibits fumigation activity against M. incognita.

Spotted wing drosophila, Drosophila suzukii (Diptera: Drosophilidae), is a serious invasive pest of berries and cherries in the U.S. and Europe and has become a major phytosanitary trade barrier. In this pilot study, we explored the potential of using stand-alone ethyl formate (EF) treatment and a combinatory treatment of EF and cold temperature as postharvest control options for D. suzukii in imported blueberries. Stand-alone EF fumigations were effective against D. suzukii with LCt99% of 207.7 and 168.5 g·h·m−3 for eggs, the most tolerant life stage, at 5 and 21 °C, respectively. In a scale-up (10 m3) trial conducted at 5 °C, complete control of D. suzukii eggs placed inside and outside of blueberry boxes was achieved using 70 g·m−3 EF for 4 h with 5% blueberry loading ratio without deleterious impact on blueberry appearance such as soft spot or berry shrivel. In small scale pilot studies, 9-d stand-alone cold treatment at 5 °C was sufficient for complete control of D. suzukii eggs and larvae tested, but not pupae. The efficacy of this cold treatment appeared to be improved when D. suzukii eggs were first treated with low-dose EF (LCt50% level) prior to the cold treatment. The combination treatment resulted in complete mortality of D. suzukii eggs, larvae, and pupae tested after 7, 5, and 9 d of cold treatment, respectively. Together, these results suggest that stand-alone EF treatment, or the combination treatment of low-dose EF and cold as a systems approach may have a potential as postharvest treatments for D. suzukii in blueberries.

Soil microbiome manipulation can potentially reduce the use of pesticides by improving the ability of soils to resist or recover from pathogen infestation, thus generating natural suppressiveness. We simulated disturbance through soil fumigation and investigated how the subsequent application of bio-organic and organic amendments reshapes the taxonomic and functional potential of the soil microbiome to suppress the pathogens Ralstonia solanacearum and Fusarium oxysporum in tomato monocultures. The use of organic amendment alone generated smaller shifts in bacterial and fungal community composition and no suppressiveness. Fumigation directly decreased F. oxysporum and induced drastic changes in the soil microbiome. This was further converted from a disease conducive to a suppressive soil microbiome due to the application of organic amendment, which affected the way the bacterial and fungal communities were reassembled. These direct and possibly indirect effects resulted in a highly efficient disease control rate, providing a promising strategy for the control of the diseases caused by multiple pathogens.

In order to develop a strategy for the safe management of insect pests in stored agricultural commodities, Anserine (Chenopodium ambrosioides (L.)) essential oil was tested against Cowpea weevil (C...

Shiitake mushrooms are one of the most popular and highly consumed mushrooms worldwide both in fresh and dry forms. However, it rapidly starts losing its quality immediately after harvest which necessitates processing and/or proper storage before being distributed. However, the processes used for preserving other mushrooms (e.g., Agaricus) become unviable for shiitake due to its uniqueness (higher respiration rate, varied biochemicals, growth, etc.) which demands individual studies on shiitake. This review starts by listing the factors and their interdependence leading to a quality decline in shiitake after harvest. Understanding well about these factors, numerous post-harvest operations preserve shiitake as fresh form for a shorter period and as dried forms for a longer shelf-life. These processes also affect the intrinsic quality and nutrients of shiitake. This review comprehensively summarizes and discusses the effects of chemical processing (washing, fumigation, coating, and ozone), modified atmosphere packaging (including irradiation) on the quality of fresh shiitake while discussing their efficiency in extending their shelf-life by inhibiting microbial spoilage and deterioration in quality including texture, appearance, nutrients, and favor. It also reviews the impact of thermal dehydration on the quality of dried shiitake mushrooms, especially the acquired unique textural, nutritional, and aromatic properties along with their merits and limitations. Since shiitake are preferred to be low-cost consumer products, the applicability of freeze-drying and sophisticated novel methodologies, which prove to be expensive and/or complex, are discussed. The review also outlines the challenges and proposes the subsequent future directives, which either retains/enhances the desirable quality in shiitake mushrooms.

This study aimed to determine the chemical composition and insecticidal activity of essential oils from Thymus vulgaris (thyme) and Cymbopogon citratus (lemongrass) against the devastating pest, Tuta absoluta. Essential oils were extracted by hydrodistillation and chemically analyzed by Gas chromatography coupled to mass spectrometry. Their knockdown (KD50) and larvicidal (LD50) activities were assessed through direct contact and fumigation toxicity assays. The major components of thyme oil were Thymol (21.53%), α-Pinene (Dextro) (17.43%) and o-Cymene (15.37%), while, Neral (34.48%), Geranial (34.37%) and β-Myrcene (12.84%) were prominent in lemongrass oil. Statistical analysis indicated that both oils exhibited similar knockdown and insecticidal efficiencies through direct contact and fumigation routes. The resultant biological parameters for lemongrass and thyme oils were KD50 values of 0.193 µL/mL and 0.592 µL/mL and LD50 values of 0.328 µL/mL and 0.608 µL/mL respectively for contact toxicity and KD50 of 1.290 µL/mL and 2.565 µL/mL and LD50 of 1.479 µL/mL and 3.046 µL/mL for lemongrass and thyme oils respectively for fumigant toxicity. The reference insecticide, Lynx (λ-cyhalothrin 15 g/L + acetamiprid 20 g/L) elicited no mortality through both routes after 4 hours of exposure. Both essential oils prolonged life cycle of insect pest through both routes as compared to the reference insecticide. However, greenhouse and open field trials are required to validate this approach prior to its implementation for T. absoluta control in tomato farms. To our knowledge, this study reports for the first time the insecticidal potential of lemongrass essential oil against T. absoluta.

This paper studied the chemical profile, cytotoxicity, and insecticidal activity of the volatile oil, as well as provided a detailed anatomy of the leaves and stems from Eugenia involucrata DC., Myrtaceae. Its volatile oil was identified by gas chromatography coupled with mass spectrometry. The insecticidal activity was performed using the volatile oil against two strains of Cimex lectularius L., using topical, residual, and fumigant methods. Cytotoxicity was verified against B16F10, MCF7, and McCoy cell lines. The cytotoxic mechanism was studied by the morphology feature changes. The microscopic analysis was performed by usual microscopy techniques. The main volatile compounds of E. involucrata were germacrene B (22.17%), bicyclogermacrene (19.76%), and β-elemene (10.86%). Volatile oil demonstrated low toxicity against two strains of the bed bug in the topical test and did not present toxicity in fumigation and residual methods. Cytotoxicity for the B16F10 murine melanoma cells was demonstrated. Moreover, the volatile oil induces morphological characteristic changes of the cell death process of apoptosis. The microscopic data of the leaf and stem provided information to support the identification of E. involucrata.

This study investigated the efficacy of using Vikane gas fumigant (sulfuryl fluoride) at the 1.9× dosage rate for eliminating bed bugs (Cimex lectularius L.) in two challenging infestation situations: personal vehicles, and confined spaces densely packed with personal belongings. The vehicles used in this study were large minivans with seating that folded into the floor. The confined spaces were cargo trailers filled to 85% capacity with books, furniture, and other household items. Each van and trailer was equipped with ~90 sentinel bed bugs consisting of three groups of 9–11 bed bug eggs, 10 nymphs, and 10 adults. The Vikane Fumiguide calculator was used to determine the target dosage (g-h/m3) to apply in each replicate (e.g., one van or trailer). Sulfuryl fluoride concentrations were measured throughout the fumigation process using a Spectros SF-ReportIR. Concentration readings were input into the Fumiguide to determine when the accumulated dosage (g-h/m3) was achieved, and when aeration should be initiated. After aeration was complete, the sentinel bed bugs were removed from the replicates and bed bug nymph and adult mortality was recorded. Bed bug eggs were monitored for 23 d to determine latent mortality. Fumigated bed bug mortality for each replication was 100% regardless of life stage. Latent mortality was observed in a single bed bug egg, but the first instar never fully eclosed. This study determined that fumigation with sulfuryl fluoride at the 1.9× dosage factor is an effective method for eliminating resistant bed bugs from vehicles and personal belongings in densely packed situations.

Fusarium graminearum is the primary cause of Fusarium head blight (FHB), one of the most economically important diseases of wheat worldwide. FHB reduces yield and contaminates grain with the trichothecene mycotoxin deoxynivalenol (DON), which poses a risk to plant, human and animal health. The first committed step in trichothecene biosynthesis is formation of trichodiene (TD). The volatile nature of TD suggests that it could be a useful intra or interspecies signalling molecule, but little is known about the potential signalling role of TD during F. graminearum-wheat interactions. Previous work using a transgenic Trichoderma harzianum strain engineered to emit TD (Th + TRI5) indicated that TD can function as a signal that can modulate pathogen virulence and host plant resistance. Herein, we demonstrate that Th + TRI5 has enhanced biocontrol activity against F. graminearum and reduced DON contamination by 66% and 70% in a moderately resistant and a susceptible cultivar, respectively. While Th + TRI5 volatiles significantly influenced the expression of the pathogenesis-related 1 (PR1) gene, the effect was dependent on cultivar. Th + TRI5 volatiles strongly reduced DON production in F. graminearum plate cultures and downregulated the expression of TRI genes. Finally, we confirm that TD fumigation reduced DON accumulation in a detached wheat head assay.

Made available in DSpace on 2022-04-28T19:30:03Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-02-01 Florida Education Fund Macrophomina phaseolina, the causal agent of charcoal rot in strawberry, induces plant wilting and collapse. The pathogen survives through the production of microsclerotia in the soil and in strawberry debris. However, its management is difficult, and the disease has become an increasing problem for the strawberry industry. Physical, cultural, and chemical alternatives for integrated management of charcoal rot were evaluated in laboratory and field trials during the 2017-18 and 2018-19 strawberry seasons. In a laboratory trial, M. phaseolina microsclerotia were subjected to heat treatment and germination was inhibited at 52, 56, 80, and 95°C after 30, 10, 1, and 0.5 min of exposure, respectively. In infected strawberry crowns, microsclerotial viability was reduced after 5 min, regardless of temperature, whereas in the field, reduction was observed after 1 min. In field trials, charcoal rot incidence of inoculated strawberry plants transplanted into white-striped plastic-mulched beds was reduced to 20.8%, compared with 60.8% for plants grown in the black plastic mulch. On commercial farms, crop residue removal from infested areas reduced the M. phaseolina population in the soil but did not decrease charcoal rot incidence. Moreover, M. phaseolina propagule densities in the soil and in strawberry debris was reduced by fumigant application at crop termination but surviving propagules allowed the population to increase over the summer. Furthermore, preplant fumigation with metam potassium reduced soil population and charcoal rot incidence. Overall, the adoption of integrated approaches such as physical, chemical, and/or cultural methods played a significant role in reducing M. phaseolina inoculum and contributed to control of the disease in areas with high disease pressure. University of Florida Gulf Coast Research and Education Center São Paulo State University College of Agricultural Sciences University of Florida Citrus Research and Education Center São Paulo State University College of Agricultural Sciences

Phosphine is the most commonly used gas for fumigation for durable commodities globally, but there is still inadequate information regarding its efficacy in conjunction with proper concentration monitoring. In a series of bioassays, insect mortality after specific exposure intervals to phosphine in selected species was examined, as well as the appearance of the so called "sweet spot". The species that were tested were: Oryzaephilus surinamensis (L.), Tribolium castaneum (Herbst), Sitophilus oryzae (L.) and Rhyzopertha dominica (F.) with populations that had different levels of phosphine resistance. Evaluation was conducted by using the Phosphine Tolerance Test (PTT), with exposure of the adult stage for 15, 30, 60, 90, 150 and 300 min at 3000 ppm. At the end of these intervals (separate bioassays for each time interval), the insects were transferred to Petri dishes, in which recovery was recorded at different time intervals (2 h, 1, 2 and 7 days). The majority of susceptible populations of all species were instantly immobilized even in the shortest exposure period (15 min), in contrast with resistant populations that were active even after 300 min. After exposure to phosphine, populations and exposure time affected mortality of susceptible populations, whereas resistant populations recovered regardless of species and exposure time. Additional bioassays at the concentrations of 500, 1000, 2000 and 3000 ppm for 1, 3, 5, 20, 30 and 40 h showed the presence of the "sweet spot", i.e., decrease of mortality with the increase of concentration. In fact, for most of the tested species, the "sweet spot" appeared in 1000 and 2000 ppm at a 5-h exposure time, regardless of the level of resistance to phosphine. This observation is particularly important both in terms of the assessment of resistance and in the context of non-linear recovery at elevated concentrations, indicating the occurrence of strong hormetic reversals in phosphine efficacy.

A coronavirus (SARS-CoV-2) has caused a global pandemic and associated morbidity and mortality resultant from COVID-19. As a result of efforts to control direct (person to person) and indirect (contaminated objects, surfaces, indoor air) transmission of the virus, various interventions have been evaluated. Studies were conducted to evaluate the efficacy of commercially available chlorine dioxide (CD) products to reduce viral loads on PPE (face masks) and surfaces using a novel dry gas release intervention. The efficacy of CD slow release 30-day sachets was tested on N95 face masks inoculated with human coronavirus OC43 in suspension. One sachet was placed with an inoculated mask in plastic resealable bags. Three trials were completed using the original sachet where a mask and sachet were placed into a plastic bag for 13 hours per sachet age of 1 day, 14 days, and 30 days. The amount of CD generated during a 13-hour treatment period was 0.30 mg. The nominal concentration of CD was estimated to be 317 mg/m3. All three tests demonstrated at least a 99.91% reduction of viral loading in the mask versus a non-treated control. Efficacy of CD dry gas fast releasing pods (Ultrashok) for fumigation was also tested in a 1344 ft3 closed room. Two pods were placed in the space and CD surface virucidal efficacy was tested in three locations of the room after 1 hour and 2 hours of dwell time. The estimated nominal peak concentration was 15 ppmv in the room. The one-hour exposure saw a >99.91% OC43 reduction on surfaces and the two-hour exposure resulted in a >99.997% OC43 reduction on surfaces versus a non-treated control. These results indicate dry CD is highly effective against human coronavirus. CD was 99.91% effective for eliminating human coronavirus OC43 in both sachet and capsule fumigant form using both fast and slow release mechanisms. Rapid fumigant application is suitable for contaminated rooms, ambulances, emergency vehicles, and many types of PPE, most particularly porous PPE materials. The gaseous state of CD allows for rapid diffusion and transfer of the virucidal stable free radical to all surfaces of PPE and indoor areas that would favor virus survival. Additionally, this work suggests CD can be effective at levels with significant margins of safety (little to no exposure and rapid degradation of residuals) providing minimal public health risks associated with the use of CD.

Context The traditional drying method, sun drying, for Chrysanthemum morifolium Ramat. cv. Hang-ju (Compositae) (HJ) is widely replaced by sulphur fumigation (SF), which has an unknown effect on its efficacy. Objective To investigate protective effects of nonfumigated HJ (NHJ) and sulphur-fumigated HJ (SHJ) water extracts against oxidative stress and lipid peroxidation. Materials and methods Sprague-Dawley rats were administered high-fat diet to induce hyperlipidaemia and randomly divided into eight groups (n = 6): control, fenofibrate, NHJ and SHJ extracts (1, 2 or 4 g crude drugs/kg/d; intragastric administration for 8 weeks). Serum total cholesterol (TC), triglyceride (TG), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), superoxide dismutase (SOD) and malondialdehyde (MDA) levels were detected. Human umbilical vein endothelial cells (HUVECs) were treated with NHJ and SHJ extracts (50, 100 or 200 μg/mL) for 24 h, followed by oxidized low-density lipoprotein (ox-LDL, 20 μg/mL) for 2 h in vitro. Cellular reactive oxygen species (ROS), SOD and MDA levels and apoptosis were evaluated. Results NHJ was more effective than SHJ in decreasing serum TG, TC, LDL-C, LDL/HDL and MDA while increasing serum HDL-C and SOD levels at high doses. SHJ (IC50=19.9 mg/mL) suppressed HUVEC growth stronger than NHJ (IC50=186.7 mg/mL). At 200 μg/mL, NHJ was more effective than SHJ in downregulating ROS and MDA levels, reducing HUVECs apoptosis rate and elevating SOD activity in ox-LDL-treated HUVECs. Conclusions SF causes oxidative damage and attenuates antioxidative activity in ox-LDL-treated HUVECs, which promotes lipid peroxidation. SF is not recommended for processing HJ.

The investigation on the management of cigarette beetle with plant leaves as fumigants was carried out with neem (Azadirachta indica), notchi (Vitex negundo), pungam (Pongamia pinnata) and eucalyptus (Eucalyptus globulus). An untreated control was maintained simultaneously. Among the treatments evaluated, in the single dose application of phyto-fumigants, the treatment, neem fumigation achieved faster cent - percent mortality compared to other treatments during fifth day. Similarly, the eucalyptus fumigation took seven days after treatment to achieve 100% mortality of released adults. Whereas, notchi and pungam fumigation took nine days for the complete mortality of released insects. In the application of double dose of phyto-fumigants, the neem and eucalyptus fumigation has achieved 85.00 per cent mortality after three days of treatment and they were statistically on par with each other followed by pungam fumigation (30.00%) which was statistically on par with notchi fumigation (25.00%). No mortality was observed in control. All the treatments have achieved 100 per cent mortality at five days after treatment. It is concluded that the application of both neem and eucalyptus fumes are effective in the control of cigarette beetle and could be used as an alternative to synthetic fumigants in stored pest management strategies by small scale farmers.

Light brown apple moth, Epiphyas postvittana, is a quarantine pest in most countries and has established in California and, therefore, has potential to affect export of fresh products from infested areas. There is currently lack of effective treatment especially against eggs. Nitric oxide is a recently discovered fumigant for postharvest pest control and is evaluated in laboratory fumigations to determine its efficacy against different life stages of this pest. Small scale fumigations with nitric oxide at 1.0%, 2.0%, 3.0%, and 5.0% concentrations were conducted under ultralow oxygen conditions at 2?C against larvae, pupae, and eggs of light brown apple moth. Treatment times ranged from 4 to 24 h depending on nitric oxide concentration and life stage. Complete control of larvae and pupae was achieved in 8 h fumigation with 2.0% NO. Eggs were successfully controlled in 6, 12, and 24 h fumigations with 5.0%, 3.0%, and 2.0% NO respectively. The study demonstrated that nitric oxide fumigation was effective against all life stages of light brown apple moth and, therefore, has potential to be an alternative treatment to methyl bromide fumigation for postharvest control of light brown apple moth.

A trial was conducted under green house condition to study the efficacy of some chemicals as soil fumigation and soil application on plant growth characters and reproduction of M. incognita infecting bell pepper. In this study, chemicals viz. metham sodium at 20 ml/m2, 30 ml/m2, 40 ml/m2, fluensulfone at 5 g/m2, 10 g/m2, 15 g/m2 and carbofuran at 20 g/m2 were applied and suitable control was also maintained for comparison. Observations on plant growth characters (shoot and root length, shoot and root weight) and nematode reproduction factors (number of galls per 5g root, number of egg masses per 5g root, nematode population/200 cc soil) and yield kg/plant were recorded. Results showed that metham sodium @ 40ml/m2 was best treatment to improve the plant growth characters, yield and reducing nematode reproduction on bell pepper.

In Washington, most winegrapes are own-rooted Vitis vinifera, which is susceptible to the plant-parasitic nematodes Meloidogyne hapla and Xiphinema americanum. Using resistant rootstocks to manage nematodes has not been evaluated in Washington vineyards. A long-term vineyard trial was established to evaluate the effects of soil fumigation and rootstock genotype on M. hapla and X. americanum population dynamics and vine growth during vineyard establishment (first three years) in a replant scenario. Vines in an existing V. vinifera ‘Chardonnay’ vineyard were first treated with foliar glyphosate in fall 2014. Randomized areas within the vineyard were then either fumigated or not with drip-applied metam sodium. Following fumigation, vines were removed. In spring 2015, the vineyard was replanted to Chardonnay on the following rootstocks: 1103 Paulsen, 101-14 Millardet et de Grasset, Teleki 5C, and Harmony. Self-grafted and own-rooted Chardonnay were included. Fumigation reduced M. hapla soil second-stage juvenile (J2) population densities on own-rooted and self-grafted vines for only the first year after fumigation. One year after fumigation, the self-grafted and own-rooted vines had higher population densities of M. hapla J2 than rootstocks. All rootstocks supported measurable densities of M. hapla J2 but were poor hosts relative to V. vinifera. Fumigation effectively reduced population densities of X. americanum for up to 3.5 years. Fumigation also reduced early establishment pruning weights. Vines grown in fumigated areas had lower pruning weights through year 2; but rootstock was the bigger influence on pruning weights by year 3. This trial demonstrates that rootstocks have a more sustained impact on nematode re-establishment and subsequent vine health in a vineyard replant scenario than that of pre-plant fumigation.