-
Scientific Reports Feb 2021Root lesion nematode (RLN; Pratylenchus thornei) causes extensive yield losses in wheat worldwide and thus pose serious threat to global food security. Reliance on...
Root lesion nematode (RLN; Pratylenchus thornei) causes extensive yield losses in wheat worldwide and thus pose serious threat to global food security. Reliance on fumigants (such as methyl bromide) and nematicides for crop protection has been discouraged due to environmental concerns. Hence, alternative environment friendly control measures like finding and deployment of resistance genes against Pratylenchus thornei are of significant importance. In the present study, genome-wide association study (GWAS) was performed using single-locus and multi-locus methods. In total, 143 wheat genotypes collected from pan-Indian wheat cultivation states were used for nematode screening. Genotypic data consisted of > 7K SNPs with known genetic positions on the high-density consensus map was used for association analysis. Principal component analysis indicated the existence of sub-populations with no major structuring of populations due to the origin. Altogether, 25 significant marker trait associations were detected with - log10 (p value) > 4.0. Three large linkage disequilibrium blocks and the corresponding haplotypes were found to be associated with significant SNPs. In total, 37 candidate genes with nine genes having a putative role in disease resistance (F-box-like domain superfamily, Leucine-rich repeat, cysteine-containing subtype, Cytochrome P450 superfamily, Zinc finger C2H2-type, RING/FYVE/PHD-type, etc.) were identified. Genomic selection was conducted to investigate how well one could predict the phenotype of the nematode count without performing the screening experiments. Prediction value of r = 0.40 to 0.44 was observed when 56 to 70% of the population was used as a training set. This is the first report where GWAS has been conducted to find resistance against root lesion nematode (P. thornei) in Indian wheat germplasm.
Topics: Animals; Genome, Plant; Genome-Wide Association Study; Nematoda; Plant Diseases; Plant Roots; Triticum
PubMed: 33574377
DOI: 10.1038/s41598-021-80996-0 -
BioMed Research International 2022Forced air heat treatment could induce defenses to protect fruit from pathogen attacks and has been applied as an alternative to methyl bromide for phytosanitary...
Forced air heat treatment could induce defenses to protect fruit from pathogen attacks and has been applied as an alternative to methyl bromide for phytosanitary treatment before exportation. However, few studies were reported on the regulation mechanism of antifungal effect and delayed physiological disorders of papaya by heat treatment. Therefore, we aim to explore the fruit's resistance to pathogens and the inhibition of physiological disorders by metabolomic profiling. In our study, papaya fruits were treated with 47.2°C for 30, 60, and 90 min by forced hot air treatment. The disease resistance against , quality parameters, and metabolites of papaya fruits were measured during 10 days of storage after heat treatment by metabolomic profiling. Papaya fruits after 30 and 60 min heat treatment had higher firmness, a delayed degreening and yellowing (lower a value) process, and a higher lightness (L) and hue angle (h) during storage. Heat treatment also delayed ripening, inhibiting the growth of and softening of papaya. Metabolites and enzymes inhibited ROS scavenging, depressed ABA-regulated respiratory, and activated phenylpropanoid metabolism. Our study provides a broad picture of fruit resistance to pathogens and the inhibition of physiological disorders by metabolomic profiling, which is induced by heat treatment.
Topics: Carica; Colletotrichum; Disease Resistance; Vegetables
PubMed: 35968234
DOI: 10.1155/2022/5162845 -
Journal of Nematology Sep 2016Steam and soil solarization were investigated for control of the root-knot nematode in 2 yr of field trials on a commercial flower farm in Florida. The objective was to...
Steam and soil solarization were investigated for control of the root-knot nematode in 2 yr of field trials on a commercial flower farm in Florida. The objective was to determine if preplant steam treatments in combination with solarization, or solarization alone effectively controlled nematodes compared to methyl bromide (MeBr). Trials were conducted in a field with naturally occurring populations of . Treatments were solarization alone, steam treatment after solarization using standard 7.6-cm-diameter perforated plastic drain tile (steam 1), steam treatment following solarization using custom-drilled plastic drain tile with 1.6-mm holes spaced every 3.8 cm (steam 2), and MeBr applied at 392 kg/ha 80:20 MeBr:chloropicrin. Drain tiles were buried approximately 35 cm deep with four tiles per 1.8 by 30 m plot. Steam application followed a 4-wk solarization period concluding in mid-October. All steam was generated using a Sioux propane boiler system. Plots were steamed for sufficient time to reach the target temperature of 70°C for 20 min. Solarization plastic was retained on the plots during steaming and plots were covered with a single layer of carpet padding to provide additional insulation. The floriculture crops larkspur ( and × ), snapdragon (), and sunflower () were produced according to standard commercial practices. One month after treatment in both years of the study, soil populations of were lower in both steam treatments and in MeBr compared to solarization alone. At the end of the season in both years, galling on larkspur, snapdragon, and sunflowers was lower in both steam treatments than in solarization. Both steam treatments also provided control of in soil at the end of the season comparable to, or exceeding that provided by MeBr. Both steam treatments also reduced in snapdragon roots comparable to, or exceeding control with MeBr. in soil increased in solarization alone. Solarization alone also had higher gall ratings on larkspur, snapdragon, and sunflower than all other treatments. Steam provided excellent control of in this study.
PubMed: 27765992
DOI: 10.21307/jofnem-2017-026 -
Insects Jun 2023The ham mite and the red-legged ham beetle are harmful pests to several high-valued stored products. The regulatory phase-out of the fumigant methyl bromide...
The ham mite and the red-legged ham beetle are harmful pests to several high-valued stored products. The regulatory phase-out of the fumigant methyl bromide necessitates the search for alternative fumigants. Propylene oxide (PPO) and ethyl formate (EF) were therefore evaluated in the laboratory for controlling these pests of dry-cured hams. Concentration-mortality studies at 25 °C of PPO and EF found that the mobile stages of the mites were very susceptible to low concentrations of 10 mg/L and less of each gas, while mite eggs were very tolerant and required 20 mg/L for PPO and 80 mg/L of EF for 100% mortality. Mixed life stage cultures of mites and beetles were treated for 24 h with either PPO or EF at 1× and 2× the estimated 99% lethal doses and confirmed effectiveness for controlling simulated pest populations. The sorptive properties of each gas in chambers with ham pieces, dog food kibbles, or fish meal were minimal for a reduction in mite toxicity when compared to treatments in empty chambers. There was no evidence that any desorbed gas occurred at a level toxic to mite eggs in any of the fumigated commodities. These fumigation studies with ham pests support further work with PPO and EF on any changes in the sensory quality of dry-cured hams for human taste and for commercial-scale fumigations toward regulatory approval.
PubMed: 37367327
DOI: 10.3390/insects14060511 -
Nature Communications Jan 2022Methyl bromide (CHBr) and methyl chloride (CHCl) are major carriers of atmospheric bromine and chlorine, respectively, which can catalyze stratospheric ozone depletion....
Methyl bromide (CHBr) and methyl chloride (CHCl) are major carriers of atmospheric bromine and chlorine, respectively, which can catalyze stratospheric ozone depletion. However, in our current understanding, there are missing sources associated with these two species. Here we investigate the effect of copper(II) on CHBr and CHCl production from soil, seawater and model organic compounds: catechol (benzene-1,2-diol) and guaiacol (2-methoxyphenol). We show that copper sulfate (CuSO) enhances CHBr and CHCl production from soil and seawater, and it may be further amplified in conjunction with hydrogen peroxide (HO) or solar radiation. This represents an abiotic production pathway of CHBr and CHCl perturbed by anthropogenic application of copper(II)-based chemicals. Hence, we suggest that the widespread application of copper(II) pesticides in agriculture and the discharge of anthropogenic copper(II) to the oceans may account for part of the missing sources of CHBr and CHCl, and thereby contribute to stratospheric halogen load.
PubMed: 35013262
DOI: 10.1038/s41467-021-27779-3 -
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 -
Insects Aug 2023is a highly polyphagous invasive pest that poses a significant quarantine threat to tropical and subtropical countries. Infested commodities in international trade...
is a highly polyphagous invasive pest that poses a significant quarantine threat to tropical and subtropical countries. Infested commodities in international trade should undergo phytosanitary treatment, and irradiation is recommended as a viable alternative to replace methyl bromide fumigation. Dose-response tests were conducted on the 2-, 4-, and 6-day-old eggs and gravid females of . using the X-ray radiation doses of 15-105 Gy with an interval of 15 Gy. Radiotolerance was compared using ANOVA, fiducial overlapping and lethal dose ratio (LDR) test, resulting in no significant difference among treatments, except for the overall mortality and LDR at LD (a dose causing 90% mortality at 95% confidence level). The estimated dose for LD was 176.5-185.2 Gy, which was validated in the confirmatory tests. No nymphs emerged from a total of 60,386 gravid females exposed to a gamma radiation dose range of 146.8-185.0 Gy in the confirmatory tests. The largest dose in confirmatory tests should be the minimum threshold for phytosanitary treatment, consequently, a minimum dose of 185 Gy is recommended for the phytosanitary irradiation treatment of papaya mealybug-infested commodities, ensuring a treatment efficacy of ≥99.9950% at 95% confidence level.
PubMed: 37623392
DOI: 10.3390/insects14080682 -
Scientific Reports Feb 2023Fusarium wilt, the most serious soil-borne pathogen, is a serious problem for tomato production worldwide. The presented study evaluated the antifungal activity against...
Fusarium wilt, the most serious soil-borne pathogen, is a serious problem for tomato production worldwide. The presented study evaluated the antifungal activity against Fusarium oxysporum f. sp. lycopersici in vitro and in vivo for nine fumigants. In addition, the research examined the possibility of enhancing the growth of tomato plants in order to increase resistance against this disease by using four chemical inducers. The results indicated that at 20 mg/L, the radial growth of the pathogen was inhibited 100% by formaldehyde and > 80% by phosphine. Among the essential oils investigated, neem oil was the most effective, however, it only achieved 40.54% at 500 mg/L. The values of EC for all fumigants, except dimethyl disulfide (DMDS) and carbon disulfide (CS2), were lower than those for thiophanate-methyl. Phosphine was the highest efficient. The elicitors can be arranged based on their effectiveness, gibberellic acid (GA3) > sorbic acid > cytokinin (6-benzylaminopurine) > indole-3-butyric acid. The change in root length, fresh weight, and dry weight was greater with soil drench than with foliar application. The fumigant generators formaldehyde, phosphine and 1,4-dichlorobenzene and bio-fumigants citrus and neem oils as well as elicitors gibberellic and sorbic acid could be one of the promising alternatives to methyl bromide against Fusarium oxysporum as an important component of integrated management of Fusarium wilt.
Topics: Fusarium; Solanum lycopersicum; Sorbic Acid; Pesticides; Soil; Plant Diseases
PubMed: 36774421
DOI: 10.1038/s41598-023-29033-w -
Methods and Protocols Dec 2018Compared to previously tested fumigants such as methyl bromide, sulfuryl fluoride and phosphine; ethanedinitrile (EDN) is a new fumigant which is being trialled around...
Compared to previously tested fumigants such as methyl bromide, sulfuryl fluoride and phosphine; ethanedinitrile (EDN) is a new fumigant which is being trialled around the world as a pre-plant soil treatment and as a quarantine and pre-shipment (QPS) treatment of commodities. To collect the data necessary to assess the effectiveness of this fumigant, an accurate analytical method is needed across a wide concentration range. We reviewed the methods of detection for EDN described in recently published fumigation studies and have developed and validated a method to quantify EDN in air using a gas chromatograph equipped with a flame ionization detector (GC-FID). Our tested method has a linearity, precision, accuracy, limit of detection (LOD) and limit of quantification (LOQ) of R 0.9988, 1.36%, 98.8%, 0.750 ppm and 1.073 ppm, respectively. These values were determined using internationally recognised guidelines for the validation of non-standard analytical methods, which means that our method can be applied to the different validation requirements of regulatory agencies and countries. Our method can be used for experimental conditions that require detection at low and high concentrations simultaneously because it is accurate, fast (0.6 min) and repeatable across a concentration range of 1 to 40,000 ppm. This method will help to standardise the quantification of EDN by research groups and facilitate acceptance of data by regulatory organisations around the world.
PubMed: 31164586
DOI: 10.3390/mps2010001 -
Insects Mar 2023Sweet persimmons are a valuable export commodity. However, the presence of live insects such as limits their access to many export markets. Methyl bromide,...
Sweet persimmons are a valuable export commodity. However, the presence of live insects such as limits their access to many export markets. Methyl bromide, traditionally used for pest control, is damaging to human health and the environment. Ethyl formate (EF) is a viable alternative; however, its effectiveness against on sweet persimmon fruit is unknown. We evaluated the effectiveness of EF fumigation in controlling present under the calyx of persimmon fruit. The hatching rate of eggs and the survival rates of nymphs and adults of at low temperatures, its LCt and LCt after EF exposure, and phytotoxic damage caused by EF were evaluated in laboratory-scale and commercial-scale tests. The dose-response tests showed that the EF LCt at 5 °C was 9.69, 42.13, and 126.13 g h m for adults, nymphs, and eggs, respectively. Commercial-scale tests demonstrated EF efficacy against all stages without causing phytotoxic effects on persimmons, though the eggs of were not completely controlled in linear low-density polyethylene (LLDPE)-packaged fruit. This study demonstrated that EF is a potential fumigant for quarantine pretreatment, especially before persimmon fruit is packed with LLDPE film, to control infesting sweet persimmon fruit.
PubMed: 37103156
DOI: 10.3390/insects14040341