Reductive soil disinfestation(RSD)is commonly employed for soil remediation in greenhouse cultivation.However,its influence on antibiotic resistance genes(ARGs)in soil remains uncertain.This study investigated the dyn...Reductive soil disinfestation(RSD)is commonly employed for soil remediation in greenhouse cultivation.However,its influence on antibiotic resistance genes(ARGs)in soil remains uncertain.This study investigated the dynamic changes in soil communities,potential bacterial pathogens,and ARG profiles under various organicmaterial treatments during RSD,including distillers’grains,potato peel,peanut vine,and peanut vine combined with charcoal.Results revealed that applying diverse organic materials in RSD significantly altered bacterial community composition and diminished the relative abundance of potential bacterial pathogens(P<0.05).The relative abundance of high-risk ARGs decreased by 10.7%-30.6%after RSD treatments,the main decreased ARG subtypeswere AAC(3)_Via,dfrA1,ErmB,lnuB,aadA.Actinobacteria was the primary host of ARGs and was suppressed by RSD.Soil physicochemical properties,such as total nitrogen,soil pH,total carbon,were crucial factors affecting ARG profiles.Our findings demonstrated that RSD treatment inhibited pathogenic bacteria and could be an option for reducing high-risk ARG proliferation in soil.展开更多
Continuous cropping leads to high incidence of soilborne diseases such as bacterial wilt caused by Ralstonia solanacearum,which poses a risk to agricultural production.Anaerobic soil disinfestation(ASD)and plant growt...Continuous cropping leads to high incidence of soilborne diseases such as bacterial wilt caused by Ralstonia solanacearum,which poses a risk to agricultural production.Anaerobic soil disinfestation(ASD)and plant growthpromoting rhizobacteria(PGPR)are considered environmentally friendly methods to control bacterial wilt.However,the underlying mechanism of the improvement of soil health and the inhibition of bacterial wilt after ASD treatment and PGPR inoculation needs further exploration.This study evaluated the effect of ASD treatment on soil improvement at pre-planting of tomato,and the effect of ASD treatment combined with the application of Bacillus velezensis Y6(BV)on soil quality,R.solanacearum abundance,and bacterial communities at 90 days before harvesting of tomato.The results showed that ASD treatment reduced R.solanacearum abundance in soil by17.6%at pre-planting and 18.7%at 90 days before harvesting,but BV inoculation did not influence R.solanacearum abundance.ASD and ASD+BV treatments effectively reduced the occurrence of bacterial wilt,improved soil nutrient status and increased soil microbial activity at 90 days before harvesting.Principal co-ordinate analysis showed that the soil bacterial community was significantly influenced by ASD treatment both at pre-planting and at 90 days before harvesting.Further investigation found that ASD contributed to the enrichment of beneficial flora(Bacillus and Streptomyces).Moreover,pH was an important environmental factor affecting the abundance of R.solanacearum in soil.Co-occurrence network analysis showed that ASD treatment significantly increased network connection of bacterial communities and the proportion of beneficial microorganisms(Proteobacteria and Firmicutes),leading to complex soil bacterial co-occurrence networks both at pre-planting and at 90 days before harvesting.Collectively,these results indicate that ASD treatment,but not microbial inoculation can enhance tomato plant resistance to bacterial wilt by improving soil quality and modulating the soil bacterial community.展开更多
The bulk peanuts were used as the materials. After ）,-ray irradiation of different doses, the peanuts were stored up at room temperature, and the degree of pest infection and gradient of mould infection were observed...The bulk peanuts were used as the materials. After ）,-ray irradiation of different doses, the peanuts were stored up at room temperature, and the degree of pest infection and gradient of mould infection were observed regularly. The results showed that insects began to appear in the unirradiated peanuts in 2 months, while after 4 months, the pest infection rate increased with the prolonged storage time, and the pest infection rate reached up to 58%-100% after 6 months of storage. However, the irradiated peanuts did not suffer from the pest infection throughout the storage. The unirradiated peanuts were contaminated by moulds after three months of storage, while the peanuts with an irradiation dose of 0.3-0.5 kGy were mildewed after 6 months of storage, while those with an irradiation dose of 1.0, 4.0 kGy had no mould after 12 months of storage. Combined with relevant international and national standards as well as the findings of scholars at home and abroad, the minimum effective irradiation dose for insect disinfestations of peanuts was 0,3 kGy, and the minimum effective irradiation dose for mildew control was 1.0 kGy, while the maximum tolerance dose was 4.0 kGy.展开更多
Due to increasing regulations and restrictions, there is an urgent need to develop effective alternatives to chemical-dependent fumigation control of soilborne pests and pathogens. Anaerobic soil disinfestation （ASD...Due to increasing regulations and restrictions, there is an urgent need to develop effective alternatives to chemical-dependent fumigation control of soilborne pests and pathogens. Anaerobic soil disinfestation （ASD） is one such alternative showing great promise for use in the control of soilborne pathogens and pests. This method involves the application of a carbon source, irrigation to field capacity, and covering the soil with a plastic tarp. While the mechanisms of ASD are not completely understood, they appear to be a combination of changes in the soil microbial community composition, production of volatile organic compounds, and the generation of lethal anaerobic conditions. The variety of materials and options for ASD application, including carbon sources, soil temperature, and plastic tarp type, influence the efficacy of pathogen sup- pression and disease control. Currently, both dry （e.g., rice bran） and liquid （e.g., ethanol） carbon sources are commonly used, but with different results depending on environmental conditions. While solarization is not an essential component of ASD, it can enhance efficacy. Understanding the mechanisms that mediate biological changes occurring in the soil during ASD will facilitate our ability to increase ASD efficacy while enhancing its commercial viability.展开更多
Soil flame disinfestation(SFD) is a form of physical disinfestation that can be used both in greenhouses and on field crops. Its use for soil disinfestation in different crop growing conditions makes it increasingly a...Soil flame disinfestation(SFD) is a form of physical disinfestation that can be used both in greenhouses and on field crops. Its use for soil disinfestation in different crop growing conditions makes it increasingly attractive for controlling soilborne pathogens and weeds. But little is known about the effect on weeds and soilbrone diseases. This study reports on greenhouses and field crops in China that determined the efficacy of SFD to control weeds, nematodes and fungi. It also determined the impact of SFD on the soil physical and chemical properties(water content, bulk density, NO3^–-N content, NH4^+-N content, conductivity and organic matter) in three field trials. A second generation SFD machine was used in these trials. SFD treatment significantly reduced weeds(>87.8%) and root-knot nematodes(Meloidogyne incognita)(>98.1%). Plant height and crop yield was significantly increased with SFD treatment. NO3^–-N and NH4^+-N increased after the SFD treatment, and there was also an increase in soil conductivity. Water content, bulk density and organic matter decreased significantly in the soil after the SFD treatment compared to the control. Soil flame disinfestation is a potential technique for controlling weeds and diseases in greenhouses or in fields. SFD is a non-chemical, safe, environmentally-friendly soil disinfection method.展开更多
Reductive soil disinfestation（RSD）, namely amending organic materials and mulching or flooding to create strong reductive status, has been widely applied to improve degraded soils.However, there is little informatio...Reductive soil disinfestation（RSD）, namely amending organic materials and mulching or flooding to create strong reductive status, has been widely applied to improve degraded soils.However, there is little information available about sulfate（SO4^2-） transformation and sulfur（S）gas emissions during RSD treatment to degraded vegetable soils, in which S is generally accumulated. To investigate the effects of liming on SO4^2-transformation and S gas emissions,two SO4^2--accumulated vegetable soils（denoted as S1 and S2） were treated by RSD, and RSD plus lime, denoted as RSD0 and RSD1, respectively. The results showed that RSD0 treatment reduced soil SO4^2-by 51% and 61% in S1 and S2, respectively. The disappeared SO4^2-was mainly transformed into the undissolved form. During RSD treatment, hydrogen sulfide（H2S）,carbonyl sulfide（COS）, and dimethyl sulfide（DMS） were detected, but the total S gas emission accounted for 〈 0.006% of total S in both soils. Compared to RSD0, lime addition stimulated the conversion of SO42-into undissolved form, reduced soil SO4^2-by 81% in S1 and 84% in S2 and reduced total S gas emissions by 32% in S1 and 57% in S2, respectively. In addition to H2S, COS and DMS, the emissions of carbon disulfide, methyl mercaptan, and dimethyl disulfide were also detected in RSD1 treatment. The results indicated that RSD was an effective method to remove SO4^2-, liming stimulates the conversion of dissolved SO4^2-into undissolved form,probably due to the precipitation with calcium.展开更多
Almond, groundnut, pinenut and walnut, were radiated (0.25 kGy) after packing in coloured and clear polyethylene bags (0.04mm) and subsequently stored for 24 weeks at room (16-36℃) and low temperatures (10-20℃). The...Almond, groundnut, pinenut and walnut, were radiated (0.25 kGy) after packing in coloured and clear polyethylene bags (0.04mm) and subsequently stored for 24 weeks at room (16-36℃) and low temperatures (10-20℃). The effect of these treatments on insect infestation and quality was studied. It was observed that radiation (0.25 kGy) treatment in combination with low temperature (10-20℃) completely checked the insect infestation of nuts during 24 weeks of storage. Peroxidation was higher in samples stored at room than at low temperature. Storage period had a marked adverse influence on sensory quality of nuts, however, samples kept at low temperature were comparatively rated higher.展开更多
To investigate the impact of anaerobic soil disinfestation(ASD)treatment with different processing duration on tomato continuous cropping soil,a total of eight treatments were designed,which included two treatment tem...To investigate the impact of anaerobic soil disinfestation(ASD)treatment with different processing duration on tomato continuous cropping soil,a total of eight treatments were designed,which included two treatment temperatures of 10℃ and 30℃,and four treatment times of 3,4,5 and 7 weeks(w).The results showed that whether the temperature was 10℃ or 30℃,the pH values,TOC and available K contents in the soil treated by the ASD method were significantly increased(P<0.05),while the EC values and NO_(3)^(-)contents in soils treated by ASD were significantly reduced compared with the untreated group(P<0.05).The Fusarium oxysporum population in soils treated by ASD decreased with the extension of the treatment time.When the treatment temperature was 30℃,the effect on the removal of the NO_(3)^(-)that had accumulated in soils treated by ASD was significantly better than the treatment temperature of 10℃(P<0.05).When soil was treated by ASD for more than 5 w at 30℃,the NH4+content in soil was significantly increased(P<0.05)compared with the untreated soil.In conclusion,NO_(3)^(-)accumulation in soils could not be completely eliminated with treatment by ASD,even when the treatment time at 10℃ was prolonged.Whether the treatment temperature was 10℃ or 30℃,the F.oxysporum population in soils treated by ASD decreased significantly with the extension of the treatment time to more than 5 w compared with treatment only for only 3 w.展开更多
Hot air and hot water treatments are practical,environmentally-friendly and non-chemical heating methods,which are widely used for postharvest insect control and quality preservation in agricultural products.Taking ap...Hot air and hot water treatments are practical,environmentally-friendly and non-chemical heating methods,which are widely used for postharvest insect control and quality preservation in agricultural products.Taking apple and pear as representative fruits,this study mainly analyzed influences of their thermal properties,diameter,and medium speed on the heating rates of fruits through their real-time measured temperatures at surface and center.Based on the reported thermal death kinetic models of the target codling moth,the minimum heating time was estimated to achieve 100%insect mortality.The results showed that the heating rates in fruits decreased gradually with the increasing depth from the surface to the center.With increasing heating time,the heating rate became small.The apple was heated faster than the pear.Hot water was more effective than hot air in treating fruits.Increasing hot air speed increased the heating rate but increasing water circulating speed had no clear effects on the heating rate.Based on the measured temperature-time history of the fruit center,the minimum heating time could be effectively determined for codling moth control through the estimated total equivalent thermal lethal time.The results could provide reliable validation data for the computer simulation and a scientific basis to improve the hot air and hot water treatments.展开更多
Baled timothy hay underwent testing at a hay processing plant in Canada to determine if mechanical compression(rebaling)could be used as a disinfestation protocol for Hessian fly(Mayetiola destructor(Say))puparia.Pres...Baled timothy hay underwent testing at a hay processing plant in Canada to determine if mechanical compression(rebaling)could be used as a disinfestation protocol for Hessian fly(Mayetiola destructor(Say))puparia.Pressure sensitive films were randomly placed throughout the hay material,on the chamber walls,and in different orientations,to assess the hay compaction unit’s ability to induce the required pressure to crash a Hessian fly puparium in the hay.Attached to the pressure films were organdy cages containing wheat seedlings infested with Hessian fly puparia.The variables which were tested included the hold time(0.5 and 2.0 s),applied pressure(10.34 and 12.41 MPa),and timothy hay quality(low-moisture first cut,high-moisture first cut and high-moisture second cut hay).A total of 36 tests were conducted.For each test,10 Hessian fly cages and 10 pressure sensitive films were used.Each test cage contained approximately 168.56 Hessian fly puparia,translating into a total Hessian fly count of 60681 for the entire field test.Analysis of the pressure sensitive films showed that 100%of the hay experienced at least 200 kPa(29 psi)of pressure.Following the 75-day post experiment emergence period,0.0066%of the puparia survived,which may be due to the fact that the emerged puparia might have not been crushed and not subjected to a pressure of at least 20.6 kPa.The applied pressures affected Hessian fly emergence by considerably reducing the number of puparia that emerged.However,Hessian fly emerged from one of the cages in two tests.Most of the Hessian fly puparia were destroyed irrespective of the applied pressure,hold time or hay quality.展开更多
The multi-billion dollar US tree nut industries rely heavily on methyl bromide fumigation for postharvest insect control and are facing a major challenge with the mandated cessation by 2005 of its use for most applica...The multi-billion dollar US tree nut industries rely heavily on methyl bromide fumigation for postharvest insect control and are facing a major challenge with the mandated cessation by 2005 of its use for most applications. There is an urgent need to develop effective and economically viable alternative treatments to replace current phytosanitary and quarantine practices in order to maintain the competitiveness of US agriculture in domestic and international markets. With the reliable heating block system, the thermal death kinetics for fifth-instar codling moth, Indianmeal moth, and navel orangeworm were determined at a heating rate of 18℃/min. A practical process protocol was developed to control the most heat resistant insect pest, fifth-instar navel orangeworm, in in-shell walnuts using a 27 MHz pilot scale radio frequency (RF) system. RF heating to 55℃ and holding in hot air for at least 5 min resulted in 100% mortality of the fifth-instar navel orangeworm. Rancidity, sensory qualities and shell characteristics were not affected by the treatments. If this method can be economically integrated into the handling process, it should have excellent potential as a disinfestation method for in-shell walnuts.展开更多
Biological soil disinfestation is an effective method to control soil-borne disease by flooding and incorporating with organic amendments, but field conditions and resources sometimes limited its practical application...Biological soil disinfestation is an effective method to control soil-borne disease by flooding and incorporating with organic amendments, but field conditions and resources sometimes limited its practical application. A laboratory experiment was conducted to develop practice guidelines on controlling Fusarium wilt, a widespread banana disease caused by Fusarium oxysporum f. sp. cubense（FOC）. FOC infested soil incorporated with rice or maize straw at rates of 1.5 tons/ha and 3.0 tons/ha was incubated under flooded or water-saturated（100% water holding capacity） conditions at 30℃ for 30 days. Results showed that FOC populations in the soils incorporated with either rice or maize straw rapidly reduced more than 90% in the first 15 days and then fluctuated till the end of incubation, while flooding alone without organic amendment reduced FOC populations slightly. The rapid and dramatic decrease of redox potential（down to- 350 m V） in straw-amended treatments implied that both anaerobic condition and strongly reductive soil condition would contribute to pathogen inactivation. Water-saturation combined with straw amendments had the comparable effects on reduction of FOC, indicating that flooding was not indispensable for inactivating FOC. There was no significant difference in the reduction of FOC observed in the straw amendments at between 1.5 and 3 tons/ha. Therefore,incorporating soil with straw（rice or maize straw） at a rate of 3.0 tons/ha under 100%water holding capacity or 1.5 tons/ha under flooding, would effectively alleviate banana Fusarium wilt caused by FOC after 15-day treating under 30℃.展开更多
In the frame of the Sino-ltalian Cooperation Program for Environmental Protection, jointly launched in the year 2000 by the Italian Ministry for Environment and Territory and Sea （IMETS） and the China State Environm...In the frame of the Sino-ltalian Cooperation Program for Environmental Protection, jointly launched in the year 2000 by the Italian Ministry for Environment and Territory and Sea （IMETS） and the China State Environmental Protection Administration （SEPA）, experimental trials were carried out in Qingzhou city （Shandong Province, China） during 2001-2003 to test several methyl bromide alternative methods to control soilborne diseases in greenhouse tomatoes. Grafting tomatoes on resistant rootstock （Lyeopersicon lycopersicum × L. hirsutum）, metham sodium applied under traditional polyethylene plastic films; metham sodium applied at low rate under virtually impermeable films and soil sotarization combined with biocontrol agents were the alternatives tested and compared to methyl bromide applied under virtually impermeable plastic films too. Collected data show that resistant rootstock （Lycopersicon tycopersicum × L. hirsutum） introduced from Italy is a promising alternative to methyl bromide for local tomato cultivars. Metham sodium applied under traditional polyethylene plastic films is an effective alternative. Moreovez virtually impermeable films demonstrate the help to reduce methyl bromide and metham sodium rates. Finally soil solarization combined with biocontrol agents does not provide satisfactory results in terms of disease control.展开更多
Reductive soil disinfestation(RSD)is an important tool for sustainable agricultural productivity.However,the differences in soil bacterial communities and their community assembly processes among RSD and other treatme...Reductive soil disinfestation(RSD)is an important tool for sustainable agricultural productivity.However,the differences in soil bacterial communities and their community assembly processes among RSD and other treatment strategies(e.g.,biochar and chemical fumigation)are still subject to open questions.In this study,soils subjected to various treatments–un-treated control(CK),chemical soil fumigation with CaCN_(2)(CF),1% biochar(1%B),3% biochar(3%B),and reductive soil disinfestation(RSD)are investigated.Soil samples were collected,incubated,and then used for growth of tomato plants.The Sloan neutral community model indicates that stochastic processes dominate in bacterial community assembly for both biochar and CF amendments.In contrast,this work shows that RSD treatment can have a strong impact on soil bacterial community composition.The relative abundance of Firmicutes increased during unplanted soil incubation,whereas Proteobacteria and Bacteroidetes dominated in the rhizosphere after planting of tomatoes.Normalized stochasticity ratio reveals that deterministic selection played an important role in the bacterial assembly under RSD amendment.We found that RSD amendment yielded lower biomass than that for other treatments after 28 days of tomato growth.Our results suggest that although RSD treatment has great potential to rebuild soil bacterial ecology by shaping bacterial communities and their assembly processes,it is important to monitor and manage soil conditions(e.g.,soil nutrients or physical properties)before planting to ensure plant productivity.展开更多
The compression and relaxation characteristics of timothy hay were investigated with respect to hay moisture content,applied load,and hay quality.Experimental trials were performed by using a Baldwin hydraulic univers...The compression and relaxation characteristics of timothy hay were investigated with respect to hay moisture content,applied load,and hay quality.Experimental trials were performed by using a Baldwin hydraulic universal testing machine model 60 HVL-1254.The applied loads ranged from 90 kN to 240 kN,in 30 kN increments.Two qualities of timothy hay were used,high quality with moisture contents of 7.44%,10.17%,12.97%,and 16.42%wet basis(w.b.),and low quality with moisture contents of 6.38%,8.67%,16.24%,and 18.94%w.b.The results indicated that the compact density of hay samples increased with increasing moisture content and applied pressure.Less maximum applied pressure was required to achieve the same compact density with increasing moisture content.Models were fitted to the applied pressure-compact density data.Relationships were developed between the model constants and the experimental variables.The use of Faborode-O’Callaghan model for bale densities less than 500 kg/m^(3) and the simple power law model for bale densities greater than 500 kg/m^(3) are the most appropriate models expressing the relationship between density and pressure during the compression of timothy hay.The relaxation of the hay samples were affected by the initial maximum applied load or pressure and the moisture content.Samples with higher moisture contents had higher percentage relaxation than low moisture content samples.The percent relaxation values ranged from 27.40%to 53.35%for the high quality hay,and for the low quality hay the values ranged from 28.80%to 53.70%.The asymptotic modulus values(EA)were influenced by the maximum applied pressure or load and moisture content.A linear relationship was developed between the asymptotic modulus,maximum applied pressure,and moisture content.展开更多
This study reports on the low temperature tolerance and cold hardiness of larvae of false codling moth, Thaumatotibia leucotreta. We found that larvae have mean critical thermal minima （lower limits of activity） of ...This study reports on the low temperature tolerance and cold hardiness of larvae of false codling moth, Thaumatotibia leucotreta. We found that larvae have mean critical thermal minima （lower limits of activity） of 6.7℃ which was influenced by feeding status. The effects of low temperature exposure and duration of exposure on larval survival were assessed and showed that the temperature at which 50% of the population survives is -11.5 ± 0.3℃ after 2 h exposure. The supercooling point （SCP, i.e., freezing temperature） was investigated using a range of cooling rates and under different conditions （feeding and hydration status） and using inoculative freezing treatments （in contact with water or orange juice）. The SCP decreased significantly from -15.6℃ to -17.4℃ after larvae were fasted for 24 h. Twenty-four hour treatments at either high or low relative humidity （95.9% or 2.4%） also significantly decreased SCP to -17.2℃ and -18.2℃ respectively. Inoculative freezing （by water contact） raised SCP from -15.6℃ to -6.8℃ which could have important implications for post-harvest sterilization. Cooling rates did not affect SCP which suggests that there is limited phenotypic plasticity of SCP during the larval life-stage, at least over the short time-scales investigated here. In conclusion, larvae of T. leucotreta are chill-susceptible and die upon freezing. These results are important in understanding this pest＇s response to temperature variation, understanding pest risk status and improving post-harvest sterilization efficacy展开更多
基金supported by the Key Research and Development Program of Shandong Province,China(No 2021CXGC010803)Pan’an County Chinese Medicine Industry Project(No.PZYF202103).
文摘Reductive soil disinfestation(RSD)is commonly employed for soil remediation in greenhouse cultivation.However,its influence on antibiotic resistance genes(ARGs)in soil remains uncertain.This study investigated the dynamic changes in soil communities,potential bacterial pathogens,and ARG profiles under various organicmaterial treatments during RSD,including distillers’grains,potato peel,peanut vine,and peanut vine combined with charcoal.Results revealed that applying diverse organic materials in RSD significantly altered bacterial community composition and diminished the relative abundance of potential bacterial pathogens(P<0.05).The relative abundance of high-risk ARGs decreased by 10.7%-30.6%after RSD treatments,the main decreased ARG subtypeswere AAC(3)_Via,dfrA1,ErmB,lnuB,aadA.Actinobacteria was the primary host of ARGs and was suppressed by RSD.Soil physicochemical properties,such as total nitrogen,soil pH,total carbon,were crucial factors affecting ARG profiles.Our findings demonstrated that RSD treatment inhibited pathogenic bacteria and could be an option for reducing high-risk ARG proliferation in soil.
基金the National Natural Science Foundation of China(31870420)the Science and Technology Program of Guangdong Province,China(2121A0505030057)。
文摘Continuous cropping leads to high incidence of soilborne diseases such as bacterial wilt caused by Ralstonia solanacearum,which poses a risk to agricultural production.Anaerobic soil disinfestation(ASD)and plant growthpromoting rhizobacteria(PGPR)are considered environmentally friendly methods to control bacterial wilt.However,the underlying mechanism of the improvement of soil health and the inhibition of bacterial wilt after ASD treatment and PGPR inoculation needs further exploration.This study evaluated the effect of ASD treatment on soil improvement at pre-planting of tomato,and the effect of ASD treatment combined with the application of Bacillus velezensis Y6(BV)on soil quality,R.solanacearum abundance,and bacterial communities at 90 days before harvesting of tomato.The results showed that ASD treatment reduced R.solanacearum abundance in soil by17.6%at pre-planting and 18.7%at 90 days before harvesting,but BV inoculation did not influence R.solanacearum abundance.ASD and ASD+BV treatments effectively reduced the occurrence of bacterial wilt,improved soil nutrient status and increased soil microbial activity at 90 days before harvesting.Principal co-ordinate analysis showed that the soil bacterial community was significantly influenced by ASD treatment both at pre-planting and at 90 days before harvesting.Further investigation found that ASD contributed to the enrichment of beneficial flora(Bacillus and Streptomyces).Moreover,pH was an important environmental factor affecting the abundance of R.solanacearum in soil.Co-occurrence network analysis showed that ASD treatment significantly increased network connection of bacterial communities and the proportion of beneficial microorganisms(Proteobacteria and Firmicutes),leading to complex soil bacterial co-occurrence networks both at pre-planting and at 90 days before harvesting.Collectively,these results indicate that ASD treatment,but not microbial inoculation can enhance tomato plant resistance to bacterial wilt by improving soil quality and modulating the soil bacterial community.
基金Supported by the Special Fund for Agro-scientific Research in the Public Interest(201103007)~~
文摘The bulk peanuts were used as the materials. After ）,-ray irradiation of different doses, the peanuts were stored up at room temperature, and the degree of pest infection and gradient of mould infection were observed regularly. The results showed that insects began to appear in the unirradiated peanuts in 2 months, while after 4 months, the pest infection rate increased with the prolonged storage time, and the pest infection rate reached up to 58%-100% after 6 months of storage. However, the irradiated peanuts did not suffer from the pest infection throughout the storage. The unirradiated peanuts were contaminated by moulds after three months of storage, while the peanuts with an irradiation dose of 0.3-0.5 kGy were mildewed after 6 months of storage, while those with an irradiation dose of 1.0, 4.0 kGy had no mould after 12 months of storage. Combined with relevant international and national standards as well as the findings of scholars at home and abroad, the minimum effective irradiation dose for insect disinfestations of peanuts was 0,3 kGy, and the minimum effective irradiation dose for mildew control was 1.0 kGy, while the maximum tolerance dose was 4.0 kGy.
基金the California Department of Food and Agriculture Fruit Tree, Nut Tree, and Grapevine Improvement Advisory Board, USA
文摘Due to increasing regulations and restrictions, there is an urgent need to develop effective alternatives to chemical-dependent fumigation control of soilborne pests and pathogens. Anaerobic soil disinfestation （ASD） is one such alternative showing great promise for use in the control of soilborne pathogens and pests. This method involves the application of a carbon source, irrigation to field capacity, and covering the soil with a plastic tarp. While the mechanisms of ASD are not completely understood, they appear to be a combination of changes in the soil microbial community composition, production of volatile organic compounds, and the generation of lethal anaerobic conditions. The variety of materials and options for ASD application, including carbon sources, soil temperature, and plastic tarp type, influence the efficacy of pathogen sup- pression and disease control. Currently, both dry （e.g., rice bran） and liquid （e.g., ethanol） carbon sources are commonly used, but with different results depending on environmental conditions. While solarization is not an essential component of ASD, it can enhance efficacy. Understanding the mechanisms that mediate biological changes occurring in the soil during ASD will facilitate our ability to increase ASD efficacy while enhancing its commercial viability.
基金supported by the National Key Research and Development Program of China (2017YFD0201600)the Beijing Innovation Consortium of Agriculture Research System, China (BAIC01-2017)
文摘Soil flame disinfestation(SFD) is a form of physical disinfestation that can be used both in greenhouses and on field crops. Its use for soil disinfestation in different crop growing conditions makes it increasingly attractive for controlling soilborne pathogens and weeds. But little is known about the effect on weeds and soilbrone diseases. This study reports on greenhouses and field crops in China that determined the efficacy of SFD to control weeds, nematodes and fungi. It also determined the impact of SFD on the soil physical and chemical properties(water content, bulk density, NO3^–-N content, NH4^+-N content, conductivity and organic matter) in three field trials. A second generation SFD machine was used in these trials. SFD treatment significantly reduced weeds(>87.8%) and root-knot nematodes(Meloidogyne incognita)(>98.1%). Plant height and crop yield was significantly increased with SFD treatment. NO3^–-N and NH4^+-N increased after the SFD treatment, and there was also an increase in soil conductivity. Water content, bulk density and organic matter decreased significantly in the soil after the SFD treatment compared to the control. Soil flame disinfestation is a potential technique for controlling weeds and diseases in greenhouses or in fields. SFD is a non-chemical, safe, environmentally-friendly soil disinfection method.
基金supported by grants from the National Natural Science Foundation of China(Nos:41301313,41330744)the Natural Science Foundation of Jiangsu Province(No.BK20140062)+1 种基金the Natural Science Foundation of the Jiangsu Higher Education Institutions of China(No.13KJA210002)the Outstanding Innovation Team in Colleges and Universities in Jiangsu Province and the Priority Academic Program Development of Jiangsu Higher Education Institutions(164320H116)
文摘Reductive soil disinfestation（RSD）, namely amending organic materials and mulching or flooding to create strong reductive status, has been widely applied to improve degraded soils.However, there is little information available about sulfate（SO4^2-） transformation and sulfur（S）gas emissions during RSD treatment to degraded vegetable soils, in which S is generally accumulated. To investigate the effects of liming on SO4^2-transformation and S gas emissions,two SO4^2--accumulated vegetable soils（denoted as S1 and S2） were treated by RSD, and RSD plus lime, denoted as RSD0 and RSD1, respectively. The results showed that RSD0 treatment reduced soil SO4^2-by 51% and 61% in S1 and S2, respectively. The disappeared SO4^2-was mainly transformed into the undissolved form. During RSD treatment, hydrogen sulfide（H2S）,carbonyl sulfide（COS）, and dimethyl sulfide（DMS） were detected, but the total S gas emission accounted for 〈 0.006% of total S in both soils. Compared to RSD0, lime addition stimulated the conversion of SO42-into undissolved form, reduced soil SO4^2-by 81% in S1 and 84% in S2 and reduced total S gas emissions by 32% in S1 and 57% in S2, respectively. In addition to H2S, COS and DMS, the emissions of carbon disulfide, methyl mercaptan, and dimethyl disulfide were also detected in RSD1 treatment. The results indicated that RSD was an effective method to remove SO4^2-, liming stimulates the conversion of dissolved SO4^2-into undissolved form,probably due to the precipitation with calcium.
文摘Almond, groundnut, pinenut and walnut, were radiated (0.25 kGy) after packing in coloured and clear polyethylene bags (0.04mm) and subsequently stored for 24 weeks at room (16-36℃) and low temperatures (10-20℃). The effect of these treatments on insect infestation and quality was studied. It was observed that radiation (0.25 kGy) treatment in combination with low temperature (10-20℃) completely checked the insect infestation of nuts during 24 weeks of storage. Peroxidation was higher in samples stored at room than at low temperature. Storage period had a marked adverse influence on sensory quality of nuts, however, samples kept at low temperature were comparatively rated higher.
基金The Academic Support Project for Top Talents of Higher Education Subject(Major)in Anhui Province(gxbjZD2022077)The AgriculturalEcological Conservation and Pollution Control Key Laboratory of Anhui Province(FECPP201901)The High-level Talent Launch Foundationof the Applied Science Research Project of Bengbu University in 2024(2024YYX54QD).
文摘To investigate the impact of anaerobic soil disinfestation(ASD)treatment with different processing duration on tomato continuous cropping soil,a total of eight treatments were designed,which included two treatment temperatures of 10℃ and 30℃,and four treatment times of 3,4,5 and 7 weeks(w).The results showed that whether the temperature was 10℃ or 30℃,the pH values,TOC and available K contents in the soil treated by the ASD method were significantly increased(P<0.05),while the EC values and NO_(3)^(-)contents in soils treated by ASD were significantly reduced compared with the untreated group(P<0.05).The Fusarium oxysporum population in soils treated by ASD decreased with the extension of the treatment time.When the treatment temperature was 30℃,the effect on the removal of the NO_(3)^(-)that had accumulated in soils treated by ASD was significantly better than the treatment temperature of 10℃(P<0.05).When soil was treated by ASD for more than 5 w at 30℃,the NH4+content in soil was significantly increased(P<0.05)compared with the untreated soil.In conclusion,NO_(3)^(-)accumulation in soils could not be completely eliminated with treatment by ASD,even when the treatment time at 10℃ was prolonged.Whether the treatment temperature was 10℃ or 30℃,the F.oxysporum population in soils treated by ASD decreased significantly with the extension of the treatment time to more than 5 w compared with treatment only for only 3 w.
基金grants from PhD Programs Foundation of Ministry of Education of China(20120204110022)Special Talent Fund of Northwest A&F University(No.Z111021101).
文摘Hot air and hot water treatments are practical,environmentally-friendly and non-chemical heating methods,which are widely used for postharvest insect control and quality preservation in agricultural products.Taking apple and pear as representative fruits,this study mainly analyzed influences of their thermal properties,diameter,and medium speed on the heating rates of fruits through their real-time measured temperatures at surface and center.Based on the reported thermal death kinetic models of the target codling moth,the minimum heating time was estimated to achieve 100%insect mortality.The results showed that the heating rates in fruits decreased gradually with the increasing depth from the surface to the center.With increasing heating time,the heating rate became small.The apple was heated faster than the pear.Hot water was more effective than hot air in treating fruits.Increasing hot air speed increased the heating rate but increasing water circulating speed had no clear effects on the heating rate.Based on the measured temperature-time history of the fruit center,the minimum heating time could be effectively determined for codling moth control through the estimated total equivalent thermal lethal time.The results could provide reliable validation data for the computer simulation and a scientific basis to improve the hot air and hot water treatments.
基金Acknowledged for their financial support are the Natural Science and Engineering Research Council(NSERC)and Saskatchewan Agriculture,Food and Rural Revitalization through Agriculture Development Fund.
文摘Baled timothy hay underwent testing at a hay processing plant in Canada to determine if mechanical compression(rebaling)could be used as a disinfestation protocol for Hessian fly(Mayetiola destructor(Say))puparia.Pressure sensitive films were randomly placed throughout the hay material,on the chamber walls,and in different orientations,to assess the hay compaction unit’s ability to induce the required pressure to crash a Hessian fly puparium in the hay.Attached to the pressure films were organdy cages containing wheat seedlings infested with Hessian fly puparia.The variables which were tested included the hold time(0.5 and 2.0 s),applied pressure(10.34 and 12.41 MPa),and timothy hay quality(low-moisture first cut,high-moisture first cut and high-moisture second cut hay).A total of 36 tests were conducted.For each test,10 Hessian fly cages and 10 pressure sensitive films were used.Each test cage contained approximately 168.56 Hessian fly puparia,translating into a total Hessian fly count of 60681 for the entire field test.Analysis of the pressure sensitive films showed that 100%of the hay experienced at least 200 kPa(29 psi)of pressure.Following the 75-day post experiment emergence period,0.0066%of the puparia survived,which may be due to the fact that the emerged puparia might have not been crushed and not subjected to a pressure of at least 20.6 kPa.The applied pressures affected Hessian fly emergence by considerably reducing the number of puparia that emerged.However,Hessian fly emerged from one of the cages in two tests.Most of the Hessian fly puparia were destroyed irrespective of the applied pressure,hold time or hay quality.
文摘The multi-billion dollar US tree nut industries rely heavily on methyl bromide fumigation for postharvest insect control and are facing a major challenge with the mandated cessation by 2005 of its use for most applications. There is an urgent need to develop effective and economically viable alternative treatments to replace current phytosanitary and quarantine practices in order to maintain the competitiveness of US agriculture in domestic and international markets. With the reliable heating block system, the thermal death kinetics for fifth-instar codling moth, Indianmeal moth, and navel orangeworm were determined at a heating rate of 18℃/min. A practical process protocol was developed to control the most heat resistant insect pest, fifth-instar navel orangeworm, in in-shell walnuts using a 27 MHz pilot scale radio frequency (RF) system. RF heating to 55℃ and holding in hot air for at least 5 min resulted in 100% mortality of the fifth-instar navel orangeworm. Rancidity, sensory qualities and shell characteristics were not affected by the treatments. If this method can be economically integrated into the handling process, it should have excellent potential as a disinfestation method for in-shell walnuts.
基金supported by the National Natural Science Foundation of China (Nos. 41222005, 41330744, 413301335)the Natural Science Foundation of Jiangsu Province (Nos. BK2010611, SBK201220477)+1 种基金Research Fund of State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences (Y412201404)the Priority Academic Program Development of Jiangsu Higher Education Institutions
文摘Biological soil disinfestation is an effective method to control soil-borne disease by flooding and incorporating with organic amendments, but field conditions and resources sometimes limited its practical application. A laboratory experiment was conducted to develop practice guidelines on controlling Fusarium wilt, a widespread banana disease caused by Fusarium oxysporum f. sp. cubense（FOC）. FOC infested soil incorporated with rice or maize straw at rates of 1.5 tons/ha and 3.0 tons/ha was incubated under flooded or water-saturated（100% water holding capacity） conditions at 30℃ for 30 days. Results showed that FOC populations in the soils incorporated with either rice or maize straw rapidly reduced more than 90% in the first 15 days and then fluctuated till the end of incubation, while flooding alone without organic amendment reduced FOC populations slightly. The rapid and dramatic decrease of redox potential（down to- 350 m V） in straw-amended treatments implied that both anaerobic condition and strongly reductive soil condition would contribute to pathogen inactivation. Water-saturation combined with straw amendments had the comparable effects on reduction of FOC, indicating that flooding was not indispensable for inactivating FOC. There was no significant difference in the reduction of FOC observed in the straw amendments at between 1.5 and 3 tons/ha. Therefore,incorporating soil with straw（rice or maize straw） at a rate of 3.0 tons/ha under 100%water holding capacity or 1.5 tons/ha under flooding, would effectively alleviate banana Fusarium wilt caused by FOC after 15-day treating under 30℃.
基金supported by the Italian Ministry for the Environment,Territory and Sea and State Environmental Protection Administration of China under the project of "Transfer of alternative technologies to the use of methyl bromide and capacity-building in the soil fumigation sector in China"
文摘In the frame of the Sino-ltalian Cooperation Program for Environmental Protection, jointly launched in the year 2000 by the Italian Ministry for Environment and Territory and Sea （IMETS） and the China State Environmental Protection Administration （SEPA）, experimental trials were carried out in Qingzhou city （Shandong Province, China） during 2001-2003 to test several methyl bromide alternative methods to control soilborne diseases in greenhouse tomatoes. Grafting tomatoes on resistant rootstock （Lyeopersicon lycopersicum × L. hirsutum）, metham sodium applied under traditional polyethylene plastic films; metham sodium applied at low rate under virtually impermeable films and soil sotarization combined with biocontrol agents were the alternatives tested and compared to methyl bromide applied under virtually impermeable plastic films too. Collected data show that resistant rootstock （Lycopersicon tycopersicum × L. hirsutum） introduced from Italy is a promising alternative to methyl bromide for local tomato cultivars. Metham sodium applied under traditional polyethylene plastic films is an effective alternative. Moreovez virtually impermeable films demonstrate the help to reduce methyl bromide and metham sodium rates. Finally soil solarization combined with biocontrol agents does not provide satisfactory results in terms of disease control.
基金funded by the National Natural Science Foundation of China(42167017)Talents of Guizhou Science and Technology Cooperation Platform([2017]5726-52)+2 种基金Guizhou Province 100-level Talent Project([2020]6010)the Key Program of Science and Technology of Guizhou Province([2020]1Z036)Ningbo Municipal Science and Technology Bureau([2021]Z047).
文摘Reductive soil disinfestation(RSD)is an important tool for sustainable agricultural productivity.However,the differences in soil bacterial communities and their community assembly processes among RSD and other treatment strategies(e.g.,biochar and chemical fumigation)are still subject to open questions.In this study,soils subjected to various treatments–un-treated control(CK),chemical soil fumigation with CaCN_(2)(CF),1% biochar(1%B),3% biochar(3%B),and reductive soil disinfestation(RSD)are investigated.Soil samples were collected,incubated,and then used for growth of tomato plants.The Sloan neutral community model indicates that stochastic processes dominate in bacterial community assembly for both biochar and CF amendments.In contrast,this work shows that RSD treatment can have a strong impact on soil bacterial community composition.The relative abundance of Firmicutes increased during unplanted soil incubation,whereas Proteobacteria and Bacteroidetes dominated in the rhizosphere after planting of tomatoes.Normalized stochasticity ratio reveals that deterministic selection played an important role in the bacterial assembly under RSD amendment.We found that RSD amendment yielded lower biomass than that for other treatments after 28 days of tomato growth.Our results suggest that although RSD treatment has great potential to rebuild soil bacterial ecology by shaping bacterial communities and their assembly processes,it is important to monitor and manage soil conditions(e.g.,soil nutrients or physical properties)before planting to ensure plant productivity.
基金support are the Natural Science and Engineering Research Council(NSERC)Saskatchewan Agriculture and Food through Agriculture Development Fund.
文摘The compression and relaxation characteristics of timothy hay were investigated with respect to hay moisture content,applied load,and hay quality.Experimental trials were performed by using a Baldwin hydraulic universal testing machine model 60 HVL-1254.The applied loads ranged from 90 kN to 240 kN,in 30 kN increments.Two qualities of timothy hay were used,high quality with moisture contents of 7.44%,10.17%,12.97%,and 16.42%wet basis(w.b.),and low quality with moisture contents of 6.38%,8.67%,16.24%,and 18.94%w.b.The results indicated that the compact density of hay samples increased with increasing moisture content and applied pressure.Less maximum applied pressure was required to achieve the same compact density with increasing moisture content.Models were fitted to the applied pressure-compact density data.Relationships were developed between the model constants and the experimental variables.The use of Faborode-O’Callaghan model for bale densities less than 500 kg/m^(3) and the simple power law model for bale densities greater than 500 kg/m^(3) are the most appropriate models expressing the relationship between density and pressure during the compression of timothy hay.The relaxation of the hay samples were affected by the initial maximum applied load or pressure and the moisture content.Samples with higher moisture contents had higher percentage relaxation than low moisture content samples.The percent relaxation values ranged from 27.40%to 53.35%for the high quality hay,and for the low quality hay the values ranged from 28.80%to 53.70%.The asymptotic modulus values(EA)were influenced by the maximum applied pressure or load and moisture content.A linear relationship was developed between the asymptotic modulus,maximum applied pressure,and moisture content.
文摘This study reports on the low temperature tolerance and cold hardiness of larvae of false codling moth, Thaumatotibia leucotreta. We found that larvae have mean critical thermal minima （lower limits of activity） of 6.7℃ which was influenced by feeding status. The effects of low temperature exposure and duration of exposure on larval survival were assessed and showed that the temperature at which 50% of the population survives is -11.5 ± 0.3℃ after 2 h exposure. The supercooling point （SCP, i.e., freezing temperature） was investigated using a range of cooling rates and under different conditions （feeding and hydration status） and using inoculative freezing treatments （in contact with water or orange juice）. The SCP decreased significantly from -15.6℃ to -17.4℃ after larvae were fasted for 24 h. Twenty-four hour treatments at either high or low relative humidity （95.9% or 2.4%） also significantly decreased SCP to -17.2℃ and -18.2℃ respectively. Inoculative freezing （by water contact） raised SCP from -15.6℃ to -6.8℃ which could have important implications for post-harvest sterilization. Cooling rates did not affect SCP which suggests that there is limited phenotypic plasticity of SCP during the larval life-stage, at least over the short time-scales investigated here. In conclusion, larvae of T. leucotreta are chill-susceptible and die upon freezing. These results are important in understanding this pest＇s response to temperature variation, understanding pest risk status and improving post-harvest sterilization efficacy
