Agriculture

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3 pages, 188 KiB

Open AccessEditorial

Sustainable Use of Pesticides

by Xiao Ran, Hadiatullah Hadiatullah, Zhiguang Yuchi, Xin Yang and Xun Zhu

Agriculture 2023, 13(7), 1393; https://doi.org/10.3390/agriculture13071393 - 13 Jul 2023

Cited by 2 | Viewed by 2253

Abstract

Pesticides serve as indispensable inputs to ensure the optimal provision of agricultural commodities, thus exerting a significant influence on the quality and yield of food [...] Full article

(This article belongs to the Special Issue Sustainable Use of Pesticides)

Research

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13 pages, 629 KiB

Open AccessArticle

Control of Spodoptera frugiperda on Fresh Corn via Pesticide Application before Transplanting

by Hailiang Han, Bin Chen, Hongxing Xu, Yan Qin, Guiyue Wang, Zhongxian Lv, Xingliang Wang and Fucheng Zhao

Agriculture 2023, 13(2), 342; https://doi.org/10.3390/agriculture13020342 - 30 Jan 2023

Cited by 5 | Viewed by 2357

Abstract

Background: Pesticide application before transplanting crops has been widely used in rice as an economical and effective method for reducing the use of chemical pesticides. This study focused on the feasibility of the application of pesticides before transplanting in a fresh corn nursery [...] Read more.

Background: Pesticide application before transplanting crops has been widely used in rice as an economical and effective method for reducing the use of chemical pesticides. This study focused on the feasibility of the application of pesticides before transplanting in a fresh corn nursery to control Spodoptera frugiperda. Methods: Three pesticides, including 35% Chlorantraniliprole WDG, 6% Spinetoram SC, and 3% Emamectin Benzoate WDG, combined with Polyorganosilicon (HTY-A8) or special flight additives (MF) as synergists were used and their toxicity was determined in the larvae of S. frugiperda feeding on sweet corn in the third leaf stage treated with 5 and 25 times the conventional field application concentration. The best combinations were tested in the field. The results showed that S. frugiperda exhibited high sensitivity to the three pesticides. The period of pest control validity of 35% Chlorantraniliprole WDG and 6% Spinetoram SC in the larvae was about 20 days, while that of 3% Emamectin Benzoate WDG was much shorter. The active component content of Chlorantraniliprole in the corn leaves was significantly higher than that of Emamectin Benzoate and Spinetoram. The pest control effects of Chlorantraniliprole were significantly promoted by HTY-A8 and MF. The field experiment showed that the control effect on S. frugiperda could last for 17 days by spraying Chlorantraniliprole or Spinetoram at 25 times the conventional concentration before transplanting, Furthermore, this method could reduce the amount of active ingredient to 4/5 or 3/4 of that found in a single field spray or seed coating treatment, respectively. Conclusions: This study puts forward a new method to effectively control S. frugiperda in the seedling stage of fresh corn. Full article

(This article belongs to the Special Issue Sustainable Use of Pesticides)

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18 pages, 2658 KiB

Open AccessArticle

Transcriptome-Based Identification and Characterization of Genes Associated with Resistance to Beta-Cypermethrin in Rhopalosiphum padi (Hemiptera: Aphididae)

by Qiuchi Li, Xinan Li, Yulin Sun, Xujun Tian, Saige Zhu, Yanbo Wang, Haifeng Gao, Caihua Shi and Xun Zhu

Agriculture 2023, 13(2), 235; https://doi.org/10.3390/agriculture13020235 - 18 Jan 2023

Cited by 2 | Viewed by 2196

Abstract

Beta-cypermethrin is one of the most widely used pyrethroid insecticides. However, its continuous and extensive use developed pests’ resistance to beta-cypermethrin. To identify candidate genes for potential resistance phenotypes and facilitate more targeted studies, we screened out a wide range of resistance-related genes [...] Read more.

Beta-cypermethrin is one of the most widely used pyrethroid insecticides. However, its continuous and extensive use developed pests’ resistance to beta-cypermethrin. To identify candidate genes for potential resistance phenotypes and facilitate more targeted studies, we screened out a wide range of resistance-related genes by comparing multiple transcripts before and after the induction of multiple agents. In this study, transcriptomes were compared to elucidate the mechanisms and genetic basis of potential resistance between Rhopalosiphum padi (R. padi) sensitive (SS) and resistant (Beta-R) strains to beta-cypermethrin (resistance ratio: 4588.48). These two strains of aphids were treated with a spray solution of lethal beta-cypermethrin concentration (i.e., LC₅₀). To obtain diverse transcripts, we obtained 17,985,440–25,478,353 clean data from different transcript groups, of which 17,183 genes were annotated. Subsequently, these transcripts were divided into multiple groups for comparison purposes to obtain more comprehensive genes related to resistance. There were 178 to 2856 differentially expressed genes (DEGs) in these transcript groups. The DEGs, including the enriched ones, were classified according to the GO and KEGG Pathway databases. Besides, some drug-resistant DEGs were related to cuticle proteins and detoxification metabolic processes. Among them, 17 genes related to cuticle protein were upregulated and 20 were downregulated, 11 genes related to P450 were upregulated and 25 were downregulated, 7 genes related to UGT were upregulated and 15 were downregulated, 2 genes related to ABC transporter were upregulated and 4 were downregulated, 2 genes related to trypsin were upregulated and 1 were downregulated. Finally, qRT-PCR by DEGs confirmed the observed trend in the RNA sequencing expression profile, and most of the results were consistent between qRT-PCR and RNA sequencing (RNA-seq). The results of this study are highly significant in understanding the resistance phenomenon in R. padi and other similar wheat aphids, establishing the valuable basis for further research in the complex mechanism of R. padi resistance to beta-cypermethrin. Full article

(This article belongs to the Special Issue Sustainable Use of Pesticides)

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14 pages, 1392 KiB

Open AccessArticle

Impact of 40 Years Use of Different Herbicide Strategies and Crop Rotations on Weed Communities in Two Sites of the Czech Republic

by Markéta Mayerová, Jan Mikulka, Michaela Kolářová and Josef Soukup

Agriculture 2023, 13(1), 102; https://doi.org/10.3390/agriculture13010102 - 29 Dec 2022

Cited by 4 | Viewed by 1879

Abstract

Understanding the impact of farming practices on the composition of weed communities has important implications for the sustainability of weed management strategies. This study analyses data from a 40-year experiment established at two sites in the Czech Republic in 1972. The impact of [...] Read more.

Understanding the impact of farming practices on the composition of weed communities has important implications for the sustainability of weed management strategies. This study analyses data from a 40-year experiment established at two sites in the Czech Republic in 1972. The impact of herbicide strategies on the weed communities was evaluated in multi-crop rotation (MCR) with 50% cereals, and simple crop rotations (SCR) with 75% cereals. The following two herbicide strategies were compared: (1) simple treatment with synthetic auxins only in the simple crop rotation, and (2) targeted herbicide combinations with particular use of sulfonylureas, triazines, ureas and synthetic auxins. Untreated plots were included for reference purposes. Results showed that crop was the major factor determining weed community composition and explained 18% of the total variation in the case of untreated controls. However, herbicide treatment reduced the crop effect to 11%. The highest average increase of Shannon’s diversity index was by 25.4% after 44 years at the untreated plots in SCR, and it decreased by 15.1% at the treated plots in MCR. Weed species evenness € increased at all plots by an average of 23%. Simpson’s dominance index decreased at untreated plots in both crop rotations and plots treated with auxins, with the highest 44.8% decrease at the untreated plots in SCR. On the contrary, Simpson’s index increased by 33,3% on the treated plots in MCR. Herbicide selection depended on the occurrence and density of target weed species, and led to greater decrease in weed diversity and population densities in the diversified crop rotations. Full article

(This article belongs to the Special Issue Sustainable Use of Pesticides)

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13 pages, 1458 KiB

Open AccessEditor’s ChoiceArticle

Sublethal Effects of Emamectin Benzoate on Fall Armyworm, Spodoptera frugiperda (Lepidoptera: Noctuidae)

by Zhuo-Kun Liu, Xue-Lin Li, Xiao-Feng Tan, Mao-Fa Yang, Atif Idrees, Jian-Feng Liu, Sai-Jie Song and Jian Shen

Agriculture 2022, 12(7), 959; https://doi.org/10.3390/agriculture12070959 - 3 Jul 2022

Cited by 22 | Viewed by 5418

Abstract

Fall armyworm (FAW), Spodoptera frugiperda (Lepidoptera: Noctuidae), is a highly invasive polyphagous pest that causes great economic losses to agricultural production. Emamectin benzoate (EMB) is one of the most popular biopesticides with high antipest, anti-parasitic and anti-nematode activities and low toxicity. The present [...] Read more.

Fall armyworm (FAW), Spodoptera frugiperda (Lepidoptera: Noctuidae), is a highly invasive polyphagous pest that causes great economic losses to agricultural production. Emamectin benzoate (EMB) is one of the most popular biopesticides with high antipest, anti-parasitic and anti-nematode activities and low toxicity. The present study was conducted to determine the lethality of EMB to FAW for 24 h. Sublethal effects of EMB on FAW parental and offspring generations were also assessed. LC₁₀, LC₂₀ and LC₅₀ EMB for 24 h on FAW third instar larvae were 0.0127 mg/L, 0.0589 mg/L, and 0.1062 mg/L, respectively. A low dose of sublethal concentrations of EMB could significantly influence the life cycle of FAW parental and offspring generations. Sublethal concentration (LC₂₀) of EMB significantly prolonged the pupal period of male and increased the pupal weight of male but not of female, and significantly delayed the oviposition period and longevity of adult FAW. In the FAW offspring generation, sublethal concentrations significantly increased the mortality of offspring pupae and pre-adults, and reduced the development time of offspring larvae and pre-adult male and female. Sublethal concentrations (LC₁₀ and LC₂₀) of EMB significantly decreased the FAW oviposition period. However, only LC₁₀ significantly reduced FAW F₁ female fecundity. No significant difference was found in the intrinsic rates of natural increase (r_m), finite rate of population increase (λ), and net reproductive rate (R₀) of FAW offspring exposed to sublethal concentrations. This is the first study to determine the sublethal concentrations of EMB on the life table parameters of two FAW generations. These findings can provide important implications for the rational utilization of FAW insecticides. Full article

(This article belongs to the Special Issue Sustainable Use of Pesticides)

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17 pages, 2418 KiB

Open AccessEditor’s ChoiceArticle

Cytpchrome P450 CYP4G68 Is Associated with Imidacloprid and Thiamethoxam Resistance in Field Whitefly, Bemisia tabaci (Hemiptera: Gennadius)

by Jinjin Liang, Jing Yang, Jinyu Hu, Buli Fu, Peipan Gong, Tianhua Du, Hu Xue, Xuegao Wei, Shaonan Liu, Mingjiao Huang, Cheng Yin, Yao Ji, Chao He, Wen Xie, Ran Wang, Xin Yang and Youjun Zhang

Agriculture 2022, 12(4), 473; https://doi.org/10.3390/agriculture12040473 - 27 Mar 2022

Cited by 24 | Viewed by 3514

Abstract

The superfamily cytochrome P450s is involved in the evolution of insecticide resistance. However, whether CYP4G68, a differentially expressed gene identified from our transcriptomics analysis, confers resistance to the world’s heavily used insecticide class neonicotinoids is unknown. Hence, we explored the role of [...] Read more.

The superfamily cytochrome P450s is involved in the evolution of insecticide resistance. However, whether CYP4G68, a differentially expressed gene identified from our transcriptomics analysis, confers resistance to the world’s heavily used insecticide class neonicotinoids is unknown. Hence, we explored the role of CYP4G68 in conferring imidacloprid and thiamethoxam resistance in Bemisia tabaci. The species B. tabaci MED developed low-to-high resistance to imidacloprid and thiamethoxam. Exposure to imidacloprid and thiamethoxam significantly increased the expression of CYP4G68. Moreover, quantitative real-time PCR analysis demonstrated that CYP4G68 was remarkably overexpressed in imidacloprid-resistant and thiamethoxam-resistant strains compared to susceptible strains. Further correlation analysis showed that CYP4G68 expression was significantly positively correlated with the associated resistance level in various strains of B. tabaci. These results suggest that the enhanced expression of CYP4G68 appears to mediate imidacloprid and thiamethoxam resistance in B. tabaci. Additionally, silencing CYP4G68 via RNA interference strongly increased the susceptibility of B. tabaci MED to imidacloprid and thiamethoxam. Collectively, this work revealed that CYP4G68 plays a vital role in imidacloprid and thiamethoxam resistance in B. tabaci MED. These findings will not only advance our understanding of the role of P450s in insecticide resistance but also provide a great potential target for the sustainable control of destructive insect pests such as whiteflies. Full article

(This article belongs to the Special Issue Sustainable Use of Pesticides)

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12 pages, 1757 KiB

Open AccessArticle

Effectiveness of Low Copper-Containing Chemicals against Olive Leaf Spot Disease Caused by Venturia oleaginea

by Amer Adawi, Samer Jarrar, Leen Almadi, Raed Alkowni, Marilita Gallo, Anna Maria D’Onghia, Roberto Buonaurio and Franco Famiani

Agriculture 2022, 12(3), 326; https://doi.org/10.3390/agriculture12030326 - 24 Feb 2022

Cited by 9 | Viewed by 3439

Abstract

The high level of copper (Cu) accumulation in the soil, the risk of surface water contamination, and the potential public health problems due to Cu entering the food chain have raised concerns on the use of Cu compounds in agriculture, including olive growing. [...] Read more.

The high level of copper (Cu) accumulation in the soil, the risk of surface water contamination, and the potential public health problems due to Cu entering the food chain have raised concerns on the use of Cu compounds in agriculture, including olive growing. As a consequence, there is worldwide regulatory pressure on agricultural systems to limit the use of Cu compounds. Hence, a field trial was carried out to evaluate the effectiveness of low copper containing chemicals to control olive leaf spot (OLS) disease caused by Venturia oleaginea. The trial was conducted in 2021 in an olive (cv. Nabali Baladi) grove in Palestine. Copper complexed with lignosulphonate and gluconate (Disper Cu Max^®) and the self-defense inducer Disper Broton GS^® were evaluated and compared to dodine and the traditionally and frequently used copper hydroxide. In addition, untreated trees were used as the control. Treatments were made in March, July, and August. In March 2021, leaves grown in 2020 were present and 100% infected. V. oleaginea infections caused defoliation in untreated and treated olive trees with varying degrees of intensity: the Control had the most defoliation, followed by copper hydroxide and Disper Cu Max^®, whereas dodine and, in particular, Disper Broton GS^® had the least. All treatments reduced symptomatic leaves but their efficacy varied significantly: copper hydroxide was the least effective, Disper Cu Max^® was intermediate, dodine and, mainly, Disper Broton GS^® were the most effective. Overall, the results are promising since Disper Cu Max^® and Disper Broton GS^® were able to significantly reduce OLS damage and the amount of copper used for treatments. Full article

(This article belongs to the Special Issue Sustainable Use of Pesticides)

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15 pages, 883 KiB

Open AccessEditor’s ChoiceArticle

Effects of Adjuvants on Spraying Characteristics and Control Efficacy in Unmanned Aerial Application

by Shilin Wang, Xue Li, Aijun Zeng, Jianli Song, Tao Xu, Xiaolan Lv and Xiongkui He

Agriculture 2022, 12(2), 138; https://doi.org/10.3390/agriculture12020138 - 20 Jan 2022

Cited by 27 | Viewed by 4593

Abstract

Pesticide application by unmanned agricultural aerial vehicles (UAVs) has rapidly developed in China and other Asian counties. Currently, tank-mix spray adjuvants are usually added into pesticide solutions to reduce spray drift and facilitate droplet deposition and control efficacy. The currently used tank-mix adjuvants [...] Read more.

Pesticide application by unmanned agricultural aerial vehicles (UAVs) has rapidly developed in China and other Asian counties. Currently, tank-mix spray adjuvants are usually added into pesticide solutions to reduce spray drift and facilitate droplet deposition and control efficacy. The currently used tank-mix adjuvants are all derived from conventional ground sprays, and their mechanisms of action in aerial applications are still unclear. In order to clarify the spraying characteristics and control efficacy of those adjuvants in aerial sprays, the performances of various types of tank-mix adjuvants were compared by analyzing droplet spectrum, drift potential index (DIX) in a wind tunnel, field deposition and control efficacy on wheat rust and aphids. The atomization results showed that the addition of adjuvants could change the droplet spectrum of liquid, and the results suggest that droplet size is an effective indicator of spray drift potential. In the field application, the meteorological conditions are complex and uncontrollable, and the effects of adjuvants on droplet deposition and distribution were not significant. Compared with the control solution, there was no significant difference in the deposition amount of each adjuvant solution, and the CVs of deposition were higher than 30%. Adding adjuvants to the spray solution can significantly improve the control efficacy of pesticides on wheat aphids and rust and also prolong the duration of the pesticide. Our results suggest that tank-mix adjuvants should be added when UAVs are used for aerial application. This study can be used as a reference to the research and development or selection of adjuvants in aerial sprays of UAVs. Full article

(This article belongs to the Special Issue Sustainable Use of Pesticides)

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17 pages, 936 KiB

Open AccessArticle

Use of Lentinan and Fluopimomide to Control Cotton Seedling Damping-Off Disease Caused by Rhizoctonia solani

by Shoumin Sun, Haohao Yan, Gang Chen, Shuai Yang, Jie Wang, Yuanxue Yang and Hongyan Wang

Agriculture 2022, 12(1), 75; https://doi.org/10.3390/agriculture12010075 - 6 Jan 2022

Cited by 6 | Viewed by 2727

Abstract

Lentinan (LNT) is a natural and functional polysaccharide isolated from Lentinus edodes fruiting bodies, which functions in stimulating the plant immune response, improving plant disease resistance and regulating plant growth. This study explores the use of LNT as a plant growth regulator and [...] Read more.

Lentinan (LNT) is a natural and functional polysaccharide isolated from Lentinus edodes fruiting bodies, which functions in stimulating the plant immune response, improving plant disease resistance and regulating plant growth. This study explores the use of LNT as a plant growth regulator and attractant in cotton production. After treatment with LNT, the content of malondialdehyde (MDA) in cotton seeds decreased, whereas the activities of polyphenol oxidase (PPO), superoxide dismutase (SOD) and peroxidase (POD) in leaves increased significantly. LNT also promoted the growth and development of cotton plants and significantly reduced the incidence of cotton damping-off disease. The relative expression of salicylic acid pathway-related genes in cotton also increased significantly. The prevention mechanism of fluopimomide was also evaluated, and the result showed lower EC₅₀ values and was effective in controlling cotton seedling disease caused by Rhizoctonia solani in both greenhouse experiments and field trials. The use of LNT and fluopimomide in controlling cotton seedling damping-off disease showed a synergistic effect in field trials. These results will provide a new insight into the agricultural application of LNT as a biological fungicide in the field of biological controls. Full article

(This article belongs to the Special Issue Sustainable Use of Pesticides)

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19 pages, 1211 KiB

Open AccessArticle

A Polysaccharide of Ganoderma lucidum Enhances Antifungal Activity of Chemical Fungicides against Soil-Borne Diseases of Wheat and Maize by Induced Resistance

by Xiu Yang, Shoumin Sun, Qiqi Chen, Zhongxiao Zhang, Jie Wang, Yali Liu and Hongyan Wang

Agriculture 2022, 12(1), 55; https://doi.org/10.3390/agriculture12010055 - 2 Jan 2022

Cited by 7 | Viewed by 3178

Abstract

Ganoderma lucidum polysaccharide (GLP), which is the primary active ingredient in G. lucidum, has been widely used in functional food and clinical medicine. However, it is rarely reported in the prevention and control of plant diseases. In this study, we found that [...] Read more.

Ganoderma lucidum polysaccharide (GLP), which is the primary active ingredient in G. lucidum, has been widely used in functional food and clinical medicine. However, it is rarely reported in the prevention and control of plant diseases. In this study, we found that the GLP can increase the germination rates and seedling heights of maize and wheat. We also found that the combination of GLP and chemical fungicides as a seed coating chemical compound has a control effect of more than 75% on the primary soil-borne diseases of the wheat and maize growing areas in both greenhouse and field trials. Furthermore, the combination of GLP and chemical fungicides prolongs the lasting period and reduces the application dosage of the chemical fungicides by half. In addition, GLP seed dressing could increase the resistance-related gene expression of the TPS and WRKY53 in maize and WMS533, NbPR1a, and RS33 in wheat. The combination of GLP and low-dose chemical fungicides proved to be an effective way to effectively prevent wheat sharp eyespot, root rot, and maize stalk rot in the wheat and maize continuous cropping areas in the North China Plain and to reduce pesticide use and increase crop yield. Full article

(This article belongs to the Special Issue Sustainable Use of Pesticides)

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13 pages, 1747 KiB

Open AccessArticle

Effect of Aviation Spray Adjuvant on Improving Control of Fusarium Head Blight and Reducing Mycotoxin Contamination in Wheat

by Xiaojing Yan, Ming Wang, Yuxiao Zhu, Xin Shi, Xiaohui Liu, Yixuan Chen, Jun Xu, Daibin Yang and Huizhu Yuan

Agriculture 2021, 11(12), 1284; https://doi.org/10.3390/agriculture11121284 - 16 Dec 2021

Cited by 13 | Viewed by 3338

Abstract

Fusarium head blight (FHB) and its mycotoxin contamination are among the main factors affecting wheat yield and quality. There is an urgent need to develop an efficient strategy to prevent and control the FHB disease and reduce the mycotoxin level in the wheat [...] Read more.

Fusarium head blight (FHB) and its mycotoxin contamination are among the main factors affecting wheat yield and quality. There is an urgent need to develop an efficient strategy to prevent and control the FHB disease and reduce the mycotoxin level in the wheat product. As a triazolinthione fungicide, prothioconazole is an effective broad-spectrum fungicide to control various diseases of wheat by foliar spraying. However, prothioconazole has potential harm to the female reproductive system, and its metabolism prothioconazole-desthio has teratogenicity. Considering this point, the plant protection unmanned aerial vehicles (UAVs) are undoubtedly a suitable choice for the field application of prothioconazole. In this work, by spraying 30% prothioconazole dispersible oil suspensions, we report that aviation spray adjuvant of methylated vegetable oil influences the control effect of wheat head blight, wheat yield, prothioconazole residues, and mycotoxin deoxynivalenol (DON) content. Adding 1.0% aviation spray adjuvant to the spray solution can significantly increase the droplet density and deposition amount in different layers of wheat canopy. The wheat yield increased by 6.94% compared with the treatment areas without spray adjuvant. Meanwhile, the prothioconazole and DON mycotoxin were not detected in the wheat grains. Based on these results, we conclude that the addition of aviation spray adjuvant can also not only ensure the high control effect of prothioconazole on FHB in wheat and increase wheat yield, but also greatly reduce the content of DON mycotoxin and ensure the safety of wheat production. This study is expected to provide theoretical guidance and data support for applying spray adjuvants in the field of plant protection UAVs in modern intensive sustainable agriculture. Full article

(This article belongs to the Special Issue Sustainable Use of Pesticides)

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12 pages, 815 KiB

Open AccessArticle

Control Potentials of Three Entomopathogenic Bacterial Isolates for the Carob Moth, Ectomyelois ceratoniae (Lepidoptera: Pyralidae) in Pomegranates

by Saqer S. Alotaibi, Hadeer Darwish, Sarah Alharthi, Akram Alghamdi, Ahmed Noureldeen, Ahmed M. Fallatah, András Fodor, Amal Al-Barty, Bander Albogami and Alaa Baazeem

Agriculture 2021, 11(12), 1256; https://doi.org/10.3390/agriculture11121256 - 11 Dec 2021

Cited by 10 | Viewed by 3000

Abstract

Ectomyelois ceratoniae (Lepidoptera: Pyralidae) is the primary pest of pomegranates in Saudi Arabia and is mostly controlled using broad-spectrum pesticides. Providing environmentally sound choices to limit reliance on chemical management is a major challenge in the control of E. ceratoniae and, as a [...] Read more.

Ectomyelois ceratoniae (Lepidoptera: Pyralidae) is the primary pest of pomegranates in Saudi Arabia and is mostly controlled using broad-spectrum pesticides. Providing environmentally sound choices to limit reliance on chemical management is a major challenge in the control of E. ceratoniae and, as a consequence, in the protection of pomegranate crops from its invasion. Entomopathogenic bacteria (EPB) symbiotically associated with entomopathogenic nematodes (EPNs) are well-known biocontrol agents of soil-dwelling or aerial pests. The bacterium symbiont (EPB) is the real insect-killing biocontrol agent, while the nematode (EPN) serves as a vector. We wondered whether the EPB vector, which is extremely vulnerable to adverse environmental conditions, like drought, high temperatures, and repellent soil microorganisms, could be omitted. We intended to evaluate the biocontrol potential of directly applied EPB cells and cell-free culture media (CFCM) on the larval instar E. ceratoniae. Xenorhabdus budapestensis DSM 16342 (EMA), X. szentirmaii DSM 16338 (EMC), and Photorhabdus luminescens ssp. laumondi (TT01) strains were used. After three days of exposure, the cells of EMA, EMC, and TT01 strains resulted in 100%, 88%, and 79.3% larval mortality rates, respectively. The applied EMA CFCM resulted in 53.7% larval mortality, indicating the presences of (at least) one extremely strong component produced by EMA. We concluded that the direct application of either the EPB cells or the CFCM must be a prospective alternative biocontrol of E. ceratoniae, especially to protect the important fruit (pomegranate, Punica granatum) cultivars. Especially, newly identified local EPB isolates could be applied as bio-pesticides for integrated management practices or organic pomegranate production. Full article

(This article belongs to the Special Issue Sustainable Use of Pesticides)

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13 pages, 2208 KiB

Open AccessArticle

Improving the Yield of Xenocoumacin 1 by P_BAD Promoter Replacement in Xenorhabdus nematophila CB6

by Youcai Qin, Fenglian Jia, Xiaohui Li, Beibei Li, Jie Ren, Xiufen Yang and Guangyue Li

Agriculture 2021, 11(12), 1251; https://doi.org/10.3390/agriculture11121251 - 10 Dec 2021

Cited by 8 | Viewed by 2975

Abstract

Xenocoumacin 1 (Xcn1), which is produced by Xenorhabdus nematophila CB6, exhibits strong inhibition activity against plant pathogens, especially fungi and oomycetes. Therefore, it has attracted interest in developing it into a novel biofungicide applicable for plant protection. However, its low yield with concomitant [...] Read more.

Xenocoumacin 1 (Xcn1), which is produced by Xenorhabdus nematophila CB6, exhibits strong inhibition activity against plant pathogens, especially fungi and oomycetes. Therefore, it has attracted interest in developing it into a novel biofungicide applicable for plant protection. However, its low yield with concomitant high cost during the fermentation process limits its widespread application. In this study, we replaced the native promoter of xcnA with the arabinose-inducible araBAD promoter (P_BAD), a well-known and widely used promoter for expressing heterologous genes, to evaluate its effects on Xcn1 yield and antimicrobial activity. Compared with wildtype strain, the fermentation yield of Xcn1 was improved from 68.5 mg/L to 249.7 mg/L (3.6-fold) and 234.9 mg/L (3.4-fold) at 0.5% and 1.0% L-arabinose concentration, respectively. We further explored the transcription level of the biosynthesis related genes of Xcn1 and found that their upregulation resulted in the yield improvement of Xcn1. Moreover, the antimicrobial activity of Xcn1 against Bacillus subtilis and Phytophthora capsici was determined by agar diffusion plate and growth inhibition assay, as expected, it was also found to be enhanced. The promoter-replacement strategy utilized here improves the yield of Xcn1 efficiently, which provides a basis for the industrial production of Xcn1. Full article

(This article belongs to the Special Issue Sustainable Use of Pesticides)

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18 pages, 1032 KiB

Open AccessEditor’s ChoiceReview

The Role of Insect Cytochrome P450s in Mediating Insecticide Resistance

by Min Ye, Bidhan Nayak, Lei Xiong, Chao Xie, Yi Dong, Minsheng You, Zhiguang Yuchi and Shijun You

Agriculture 2022, 12(1), 53; https://doi.org/10.3390/agriculture12010053 - 1 Jan 2022

Cited by 36 | Viewed by 8507

Abstract

In many organisms, cytochrome P450 enzymes are the primary detoxifying enzymes. Enhanced P450 activity can be mediated by the emergence of new genes, increased transcription due to mutations in the promoter regions, changes in enzyme structures and functions due to mutations in protein-coding [...] Read more.

In many organisms, cytochrome P450 enzymes are the primary detoxifying enzymes. Enhanced P450 activity can be mediated by the emergence of new genes, increased transcription due to mutations in the promoter regions, changes in enzyme structures and functions due to mutations in protein-coding regions, or changes in post-translational modifications; all of these changes are subject to insecticide selection pressure. Multiple signalling pathways and key effector molecules are involved in the regulation of insect P450s. Increased P450 activity is a key mechanism inducing insect resistance. Hence, downregulation of selected P450s is a promising strategy to overcome this resistance. Insect P450 inhibitors that act as insecticide synergists, RNA interference to induce P450 gene silencing, and the use of transgenic insects and crops are examples of strategies utilized to overcome resistance. This article reviews the latest advances in studies related to insect P450s-mediated agrochemical resistance, with focuses on the regulatory mechanisms and associated pest management strategies. Future investigations on the comprehensive regulatory pathways of P450-mediated detoxification, identification of key effectors, and downregulation strategies for P450s will ecologically, economically, and practically improve pest management. Full article

(This article belongs to the Special Issue Sustainable Use of Pesticides)

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