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Rodbell EA, Caron CG, Rondon SI, Masood MU, Wanner KW. Alfalfa weevils (Coleoptera: Curculionidae) in the western United States are resistant to multiple type II pyrethroid insecticides. J Econ Entomol 2024; 117:280-292. [PMID: 38007391 PMCID: PMC10860156 DOI: 10.1093/jee/toad218] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/18/2023] [Revised: 10/29/2023] [Accepted: 11/22/2023] [Indexed: 11/27/2023]
Abstract
The alfalfa weevil (Hypera postica Gyllenhal (Coleoptera: Curculionidae)), a key pest of alfalfa (Medicago sativa L. (Fabales: Fabacae)) across the US, has developed resistance to pyrethroids lambda-cyhalothrin and zeta-cypermethrin in at least 6 western US states. Unfortunately, 6 pyrethroid active ingredients represent most commercial insecticides registered for alfalfa weevil control in forage alfalfa systems. Thus, the loss of efficacy of this mode of action group due to multiple resistance represents a significant agricultural challenge because of a limited registered alternative mode of actions. To evaluate the extent and severity of resistance among pyrethroids around the United States, laboratory bioassays using larvae from Arizona, California, Montana, Oregon, Washington, and Wyoming, including both the Egyptian and western strains, were conducted. Results indicated that similar degrees of resistance among type II pyrethroids as determined by both laboratory bioassays and field trials exist. The LC50 values of alpha-cypermethrin, beta-cyfluthrin and zeta-cypermethrin produced significant correlations with the LC50 values of lambda-cyhalothrin. In contrast, resistance did not include type I pyrethroid, bifenthrin (registered for seed alfalfa production), whose LC50 values yielded a slope not significantly different from zero when correlated with lambda-cyhalothrin. Field trials conducted in Arizona, Montana, and Washington corroborated laboratory results, as commercial formulations with type II pyrethroid active ingredients failed to adequately control alfalfa weevils resistant to lambda-cyhalothrin. Integrated resistance management recommendations are discussed.
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Affiliation(s)
- Erika A Rodbell
- Department of Plant Science and Plant Pathology, Montana State University, 119 Plant BioScience, Bozeman, MT 59717-3150, USA
| | - Christopher G Caron
- Department of Plant Science and Plant Pathology, Montana State University, 119 Plant BioScience, Bozeman, MT 59717-3150, USA
| | - Silvia I Rondon
- Oregon IPM Center, Oregon State University, Coast Range Building, 4575 Research Way, Corvallis, OR 97333, USA
| | - M Umer Masood
- Department of Plant Science and Plant Pathology, Montana State University, 119 Plant BioScience, Bozeman, MT 59717-3150, USA
| | - Kevin W Wanner
- Department of Plant Science and Plant Pathology, Montana State University, 119 Plant BioScience, Bozeman, MT 59717-3150, USA
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Godeau C, Morin-Crini N, Crini G, Guillemin JP, Voisin AS, Dousset S, Rocchi S. Field-Crop Soils in Eastern France: Coldspots of Azole-Resistant Aspergillus fumigatus. J Fungi (Basel) 2023; 9:618. [PMID: 37367554 DOI: 10.3390/jof9060618] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Revised: 05/19/2023] [Accepted: 05/25/2023] [Indexed: 06/28/2023] Open
Abstract
Triazole fungicides are widely used to treat fungal pathogens in field crops, but very few studies have investigated whether fields of these crops constitute hotspots of azole resistance in Aspergillus fumigatus. Soil samples were collected from 22 fields in two regions of eastern France and screened for triazole residues and azole-resistant A. fumigatus (ARAf). Real-time quantitative PCR (qPCR) was used to quantify A. fumigatus in these soil samples. All the plots contained tebuconazole at concentrations from 5.5 to 19.1 ng/g of soil, and 5 of the 22 plots also contained epoxiconazole. Only a few fungal isolates were obtained, and no ARAf was detected. A. fumigatus qPCR showed that this fungal species was, on average, 5000 times more common in soil from flowerbeds containing ARAf than in soil from field crops. Thus, field-crop soils do not appear to promote A. fumigatus development, even if treated with azole fungicides, and cannot be considered hotspots of resistance. Indeed, our results suggest that they are instead a coldspot of resistance and highlight how little is known about the ecological niche of this species.
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Affiliation(s)
- Chloé Godeau
- Chrono-Environnement UMR6249, CNRS Franche-Comté University, 25000 Besançon, France
| | - Nadia Morin-Crini
- Chrono-Environnement UMR6249, CNRS Franche-Comté University, 25000 Besançon, France
| | - Grégorio Crini
- Chrono-Environnement UMR6249, CNRS Franche-Comté University, 25000 Besançon, France
| | | | - Anne-Sophie Voisin
- Agroécologie, INRAE, Institut Agro, Bourgogne University, 21000 Dijon, France
| | - Sylvie Dousset
- Laboratoire Interdisciplinaire des Environnements Continentaux, UMR 7360 Lorraine University/CNRS, 54506 Vandoeuvre lès Nancy, France
| | - Steffi Rocchi
- Chrono-Environnement UMR6249, CNRS Franche-Comté University, 25000 Besançon, France
- Parasitology-Mycology Department, University Hospital of Besançon, 25000 Besançon, France
- Smaltis, Bioinnovation, 4 Rue Charles Bried, 25000 Besançon, France
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3
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Wang Z, Chen J, Lee CJ. First Report of Anthracnose Leaf Spot Caused by Colletotrichum americae-borealis on Oat in China. Plant Dis 2022; 106:PDIS10212364PDN. [PMID: 35072490 DOI: 10.1094/pdis-10-21-2364-pdn] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Affiliation(s)
- Zhaoyu Wang
- Department of Food Science and Biotechnology, Wonkwang University, Iksan 54538, Republic of Korea
- School of Biological Science and Engineering, Xingtai University, Xingtai 054001, China
| | - Jinlong Chen
- Department of Food Science and Biotechnology, Wonkwang University, Iksan 54538, Republic of Korea
- School of Biological Science and Engineering, Xingtai University, Xingtai 054001, China
| | - Chang Joo Lee
- Department of Food Science and Biotechnology, Wonkwang University, Iksan 54538, Republic of Korea
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Helton ML, Tinsley NA, McMechan AJ, Hodgson EW. Developing an Injury Severity to Yield Loss Relationship for Soybean Gall Midge (Diptera: Cecidomyiidae). J Econ Entomol 2022; 115:767-772. [PMID: 35511081 DOI: 10.1093/jee/toac038] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/06/2022] [Indexed: 06/14/2023]
Abstract
Soybean gall midge, Resseliella maxima Gagné (Diptera: Cecidomyiidae), is a newly identified pest confirmed on soybean, Glycine max (L.) Merr. (Fabales: Fabaceae). To date, soybean gall midge has been found in Nebraska, Iowa, South Dakota, Minnesota, and Missouri, and has caused severe economic loss to commercial fields since 2018. Much is still unknown about this pest, so research efforts have been focused on biology and management. Larvae feed on the inside of the stem just above the soil line and are difficult to access and time-consuming to sample. In order to accelerate nondestructive sampling efforts, we developed an injury rating system to quantify the severity of plant injury from soybean gall midge larvae. Research plots from 2019 and 2020 in Iowa and Nebraska were evaluated for injury throughout the growing season and yield was measured. Our objective was to describe the relationship between injury severity and yield loss caused from soybean gall midge. A nonlinear regression model was developed to validate our injury rating system and to express the relationship between season long injury severity and yield loss. Results from our analysis indicate the injury rating system we developed correlates well with yield loss caused by larvae and may be an important tool for understanding the economic impact of this emergent pest of soybeans.
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Affiliation(s)
- Mitchell L Helton
- Department of Entomology, Iowa State University, Ames, IA 50011, USA
| | | | - Anthony J McMechan
- Eastern Nebraska Research and Extension Center, University of Nebraska-Lincoln, Ithaca, NE 68033, USA
| | - Erin W Hodgson
- Department of Entomology, Iowa State University, Ames, IA 50011, USA
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Singh V, Lakshman DK, Roberts DP, Ismaiel A, Hooda KS, Gogoi R. Morphopathological and Molecular Morphometric Characterization of Waitea circinata var. prodigus Causing a Novel Sheath Spot Disease of Maize in India. Plant Dis 2022; 106:526-534. [PMID: 34261356 DOI: 10.1094/pdis-05-21-0951-re] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Maize brown sheath spot (MBSS), a new disease of maize, was discovered while surveying for maize leaf and sheath blight diseases in the Indian states of Assam, Jharkhand, Meghalaya, Manipur, and Odisha. Maize is the third most important cereal after rice and wheat in India. Unlike banded leaf and sheath blight disease caused by Rhizoctonia solani, MBSS symptoms on maize were discrete and limited to sheaths only. Symptoms of MBSS in the field were initially water-soaked necrotic lesions of 1 to 2 cm in diameter on the lowermost leaf sheaths, which then progressed to the upper sheaths. Lesions coalesced and covered approximately 2 to 5% of the sheath area. Infected dried lower leaves were shed, whereas infected upper leaves remained on the stem. The pathogen was isolated, characterized morphologically, pathologically, and molecularly, and identified as Waitea circinata var. prodigus, a basidiomycete known to cause basal leaf blight of seashore paspalum. The internal transcribed spacer (ITS) sequence 2 (ITS2) of rDNA from MBSS isolates formed a well supported clade with known W. circinata var. prodigus isolates. Molecular morphometric analysis of the ITS2 regions of the five known varieties of W. circinata detected distinguishing variations in GC content, compensatory base changes (CBCs), hemi- CBCs, indels, and altered base-pairing of helices. Variation in these characteristics may indicate that varieties are distinct biological species within W. circinata sensu lato. The geographical distribution and potential impacts of MBSS on the maize crop in India necessitate further investigations of pathogen identification and disease management.
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Affiliation(s)
- Vimla Singh
- Department of Botany and Plant Physiology, Chaudhary Charan Singh Haryana Agricultural University, Regional Research Station, Karnal 132001, India
| | - Dilip K Lakshman
- Sustainable Agricultural Systems Laboratory, U.S. Department of Agriculture, Agricultural Research Service, Beltsville, MD 20705, U.S.A
| | - Daniel P Roberts
- Sustainable Agricultural Systems Laboratory, U.S. Department of Agriculture, Agricultural Research Service, Beltsville, MD 20705, U.S.A
| | - Adnan Ismaiel
- Sustainable Agricultural Systems Laboratory, U.S. Department of Agriculture, Agricultural Research Service, Beltsville, MD 20705, U.S.A
| | - K S Hooda
- Germplasm Evaluation Division, Indian Council of Agricultural Research, National Bureau of Plant Genetic Resources, New Delhi 110012, India
| | - Robin Gogoi
- Division of Plant Pathology, Indian Council of Agricultural Research, Indian Agricultural Research Institute, New Delhi 110012, India
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6
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Song Q, Van Rie J, Den Boer B, Galle A, Zhao H, Chang T, He Z, Zhu XG. Diurnal and Seasonal Variations of Photosynthetic Energy Conversion Efficiency of Field Grown Wheat. Front Plant Sci 2022; 13:817654. [PMID: 35283909 PMCID: PMC8914475 DOI: 10.3389/fpls.2022.817654] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2021] [Accepted: 01/17/2022] [Indexed: 05/22/2023]
Abstract
Improving canopy photosynthetic light use efficiency and energy conversion efficiency (ε c ) is a major option to increase crop yield potential. However, so far, the diurnal and seasonal variations of canopy light use efficiency (LUE) and ε c are largely unknown due to the lack of an efficient method to estimate ε c in a high temporal resolution. Here we quantified the dynamic changes of crop canopy LUE and ε c during a day and a growing season with the canopy gas exchange method. A response curve of whole-plant carbon dioxide (CO2) flux to incident photosynthetically active radiation (PAR) was further used to calculate ε c and LUE at a high temporal resolution. Results show that the LUE of two wheat cultivars with different canopy architectures at five stages varies between 0.01 to about 0.05 mol CO2 mol-1 photon, with the LUE being higher under medium PAR. Throughout the growing season, the ε c varies from 0.5 to 3.7% (11-80% of the maximal ε c for C3 plants) with incident PAR identified as a major factor controlling variation of ε c . The estimated average ε c from tillering to grain filling stages was about 2.17%, i.e., 47.2% of the theoretical maximal. The estimated season-averaged radiation use efficiency (RUE) was 1.5-1.7 g MJ-1, which was similar to the estimated RUE based on biomass harvesting. The large variations of LUE and ε c imply a great opportunity to improve canopy photosynthesis for greater wheat biomass and yield potential.
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Affiliation(s)
- Qingfeng Song
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China
| | - Jeroen Van Rie
- BASF Belgium Coordination Center – Innovation Center Gent, Ghent, Belgium
| | - Bart Den Boer
- BASF Belgium Coordination Center – Innovation Center Gent, Ghent, Belgium
| | - Alexander Galle
- BASF Belgium Coordination Center – Innovation Center Gent, Ghent, Belgium
| | - Honglong Zhao
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China
| | - Tiangen Chang
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China
| | - Zhonghu He
- Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Xin-Guang Zhu
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China
- *Correspondence: Xin-Guang Zhu,
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Acharya J, Moorman TB, Kaspar TC, Lenssen AW, Gailans S, Robertson AE. Effect of Planting into a Green Winter Cereal Rye Cover Crop on Growth and Development, Seedling Disease, and Yield of Corn. Plant Dis 2022; 106:114-120. [PMID: 34253039 DOI: 10.1094/pdis-04-21-0836-re] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Terminating winter cereal rye (Secale cereale L.) cover crops ≥10 days before planting (DBP) corn is recommended to minimize seedling disease and potential yield loss. In Iowa, cold temperatures and frequent precipitation can prevent farmers from following that recommendation and sometimes force them to plant corn while the rye plants are still green, referred to as "planting green" (PG). A field trial was established to evaluate the effect of rye termination shortly before or after corn planting on growth, seedling root disease, and yield of corn. A rye cover crop was terminated 17 and 3 DBP and 6 and 12 days after planting (DAP) corn; corn planted following no rye was included as a control. Rye biomass, C/N ratio, and N accumulation increased when terminated 6 or 12 DAP corn compared with rye terminated 17 or 3 DBP corn. Corn seedlings were taller from the PG treatments. More radicle root rot was observed when rye was terminated 3 DBP, 6 DAP, and 12 DAP corn than for the 17 DBP treatment and the no-rye control. Generally, greater Pythium clade B populations were detected on radicles and seminal roots of corn from the PG treatments. Corn populations, ears, or barren plants were not affected by the treatments. In both years, the no-rye control had the greatest corn yield and the 12 DAP treatment had the lowest yield. Our results suggest that PG increased corn seedling root disease and contributed to reduced corn yield.
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Affiliation(s)
- J Acharya
- Department of Plant Pathology and Microbiology, Iowa State University, Ames, IA 50011
| | - T B Moorman
- National Laboratory for Agriculture and the Environment, U.S. Department of Agriculture Agricultural Research Service, Ames, IA 50011
| | - T C Kaspar
- National Laboratory for Agriculture and the Environment, U.S. Department of Agriculture Agricultural Research Service, Ames, IA 50011
| | - A W Lenssen
- Department of Agronomy, Iowa State University, Ames, IA 50011
| | - S Gailans
- Practical Farmers of Iowa, Ames, IA 50010
| | - A E Robertson
- Department of Plant Pathology and Microbiology, Iowa State University, Ames, IA 50011
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Rodbell EA, Wanner KW. First Report of Alfalfa Weevil (Coleoptera: Curculionidae) Resistance to Lambda-Cyhalothrin in Montana. J Econ Entomol 2021; 114:2088-2095. [PMID: 34343288 DOI: 10.1093/jee/toab152] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/18/2021] [Indexed: 06/13/2023]
Abstract
Forage alfalfa (Medicago sativa L. [Fabales: Fabacae]) is a major agronomic crop grown nationally and Montana ranks highly in acres harvested. The alfalfa weevil (Hypera postica Gyllenhal [Coleoptera: Curculionidae]) is the primary defoliating pest that requires insecticide applications to prevent yield loss, particularly pyrethroid active ingredients (a.i.) that are both efficacious and cost-effective. Reports from commercial alfalfa producers in Big Horn County, MT, suggested local populations of alfalfa weevil had developed resistance to the pyrethroid a.i. lambda-cyhalothrin (type II pyrethroid). Chemical control is an important component of integrated pest management (IPM) of alfalfa weevil and the loss of pyrethroid a.i. as an effective tool would result in additional production costs. Two locations in southern Big Horn County and nine locations in four other Montana counties where resistance has not been reported were sampled and assayed for resistance to lambda-cyhalothrin. Populations from three counties were susceptible, the concentration causing 50% mortality (LC50) ranged from 0.02 to 0.10 µg/cm2. In contrast, populations from Big Horn County did not reach 50% mortality at the highest concentration of lambda-cyhalothrin tested (3.30 µg/cm2), indicating high levels of resistance have developed in these populations. A field trial in Big Horn County supported laboratory results of resistance; lambda-cyhalothrin at the highest label rate did not reduce alfalfa weevil populations. Additional bioassays suggest cross-resistance to zeta-cypermethrin (type II pyrethroid), but only partial cross-resistance to permethrin (type I pyrethroid).
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Affiliation(s)
- Erika A Rodbell
- Department of Plant Science and Plant Pathology, Montana State University, 119 Plant BioSciences, Bozeman, MT 59717-3150, USA
| | - Kevin W Wanner
- Department of Plant Science and Plant Pathology, Montana State University, 119 Plant BioSciences, Bozeman, MT 59717-3150, USA
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Upadhaya A, Yan G, Pasche J. Reproduction Ability and Growth Effect of Pin Nematode, Paratylenchus nanus, With Selected Field Pea Cultivars. Plant Dis 2019; 103:2520-2526. [PMID: 31432776 DOI: 10.1094/pdis-12-18-2136-re] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Greenhouse experiments were conducted to determine the reproductive ability and effect of the pin nematode Paratylenchus nanus from North Dakota on field pea cultivars. Reproduction of P. nanus was determined on seven field pea cultivars using naturally infested field soils at low (1,500/kg of soil) and high (4,500/kg soil) initial pin nematode densities. Nematode effect on plant growth and seed yield was evaluated at 4,500 P. nanus per 1 kg of soil by artificially inoculating P. nanus on six field pea cultivars. Reproductive factor (RF) of P. nanus was observed to be greater at the low density than the high density of the nematode. At the low population density, RF values ranged from 1.10 to 11.20, whereas at the high density, RF ranged from 1.20 to 2.50. In experiments evaluating P. nanus effects on cultivar growth, the nematode (4,500 P. nanus per 1 kg soil) caused reduction (P < 0.05) of plant height in most cultivars tested, and it also significantly impacted dry shoot weight and dry seed weight in some experiments. Plant height and shoot weight reductions were the highest in the cultivar Arcadia (up to 37 and 53%, respectively), with a dry seed weight reduction up to 32%. This research demonstrated for the first time the negative impact of P. nanus on field peas in controlled greenhouse conditions, which is an important step toward developing effective management strategies to improve the productivity of this leguminous crop.
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Affiliation(s)
- Arjun Upadhaya
- Department of Plant Pathology, North Dakota State University, Fargo, ND 58108-6050
| | - Guiping Yan
- Department of Plant Pathology, North Dakota State University, Fargo, ND 58108-6050
| | - Julie Pasche
- Department of Plant Pathology, North Dakota State University, Fargo, ND 58108-6050
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Fahy B, Siddiqui H, David LC, Powers SJ, Borrill P, Uauy C, Smith AM. Final grain weight is not limited by the activity of key starch-synthesising enzymes during grain filling in wheat. J Exp Bot 2018; 69:5461-5475. [PMID: 30165455 PMCID: PMC6255701 DOI: 10.1093/jxb/ery314] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/09/2018] [Accepted: 08/20/2018] [Indexed: 05/24/2023]
Abstract
Since starch is by far the major component of the mature wheat grain, it has been assumed that variation in the capacity for starch synthesis during grain filling can influence final grain weight. We investigated this assumption by studying a total of 54 wheat genotypes including elite varieties and landraces that were grown in two successive years in fields in the east of England. The weight, water content, sugars, starch, and maximum catalytic activities of two enzymes of starch biosynthesis, ADP-glucose pyrophosphorylase and soluble starch synthase, were measured during grain filling. The relationships between these variables and the weights and starch contents of mature grains were analysed. Final grain weight showed few or no significant correlations with enzyme activities, sugar levels, or starch content during grain filling, or with starch content at maturity. We conclude that neither sugar availability nor enzymatic capacity for starch synthesis during grain filling significantly influenced final grain weight in our field conditions. We suggest that final grain weight may be largely determined by developmental processes prior to grain filling. Starch accumulation then fills the grain to a physical limit set by developmental processes. This conclusion is in accord with those from previous studies in which source or sink strength has been artificially manipulated.
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Affiliation(s)
- Brendan Fahy
- John Innes Centre, Norwich Research Park, Norwich, UK
| | | | - Laure C David
- John Innes Centre, Norwich Research Park, Norwich, UK
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Venugopal PD, Dively GP, Lamp WO. Spatiotemporal Dynamics of the Invasive Halyomorpha halys (Hemiptera: Pentatomidae) in and Between Adjacent Corn and Soybean Fields. J Econ Entomol 2015; 108:2231-41. [PMID: 26453711 DOI: 10.1093/jee/tov188] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2014] [Accepted: 06/12/2015] [Indexed: 06/05/2023]
Abstract
Knowledge on movement and spatial patterns of insect pest populations among preferred hosts aids in the development of effective pest management strategies. In this study, we quantified the spatiotemporal dynamics of the invasive brown marmorated stink bug, Halyomorpha halys (Stål 1855), in relation to field corn, Zea mays L., and soybean, Glycine max (L.), crop phenology. We also examined the potential role of corn as a source of stink bugs in adjacent soybean. The highest density of stink bugs in each crop coincided with blister to milk-dough stages in corn (R2-R3/R4), and beginning seed to full seed (R5-R6) stages in soybean. In entire fields of adjacent corn and soybean, H. halys was found in very low density (<0.5/m(2)) or absent beyond 25 m from the field edge. Inverse distance weighted interpolations of H. halys densities suggest potential dispersal of H. halys, particularly adults and large nymphs, from corn into soybean, coinciding with the end of dough stage in corn and beginning of soybean seed development stage. These findings have important implications for managing H. halys through location and timing of scouting efforts, consideration of crop arrangement, and decisions on management interventions. Repeated scouting of field corn to assess H. halys densities, particularly from blister stage onwards, could inform decisions on management interventions for preventing or mitigating H. halys colonization into soybean. Where H. halys is an economic problem, reducing the extent of boundary shared between corn and soybean could reduce dispersal into soybean.
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Affiliation(s)
- P Dilip Venugopal
- Department of Entomology, University of Maryland, 4112 Plant Sciences Bldg., College Park, MD 20742.
| | - Galen P Dively
- Department of Entomology, University of Maryland, 4112 Plant Sciences Bldg., College Park, MD 20742
| | - William O Lamp
- Department of Entomology, University of Maryland, 4112 Plant Sciences Bldg., College Park, MD 20742
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12
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Jeon HY, Tian LF, Zhu H. Robust crop and weed segmentation under uncontrolled outdoor illumination. Sensors (Basel) 2011; 11:6270-83. [PMID: 22163954 DOI: 10.3390/s110606270] [Citation(s) in RCA: 82] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/18/2011] [Revised: 05/18/2011] [Accepted: 06/07/2011] [Indexed: 11/21/2022]
Abstract
An image processing algorithm for detecting individual weeds was developed and evaluated. Weed detection processes included were normalized excessive green conversion, statistical threshold value estimation, adaptive image segmentation, median filter, morphological feature calculation and Artificial Neural Network (ANN). The developed algorithm was validated for its ability to identify and detect weeds and crop plants under uncontrolled outdoor illuminations. A machine vision implementing field robot captured field images under outdoor illuminations and the image processing algorithm automatically processed them without manual adjustment. The errors of the algorithm, when processing 666 field images, ranged from 2.1 to 2.9%. The ANN correctly detected 72.6% of crop plants from the identified plants, and considered the rest as weeds. However, the ANN identification rates for crop plants were improved up to 95.1% by addressing the error sources in the algorithm. The developed weed detection and image processing algorithm provides a novel method to identify plants against soil background under the uncontrolled outdoor illuminations, and to differentiate weeds from crop plants. Thus, the proposed new machine vision and processing algorithm may be useful for outdoor applications including plant specific direct applications (PSDA).
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Hollaway GJ, Taylor SP, Eastwood RF, Hunt CH. Effect of Field Crops on Density of Pratylenchus in SouthEastern Australia; Part 2: P. thornei. J Nematol 2000; 32:600-608. [PMID: 19271015 PMCID: PMC2620497] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/27/2023] Open
Abstract
The effect of 93 field crop and pasture cultivars on the end-of-season population densities of Pratylenchus thornei in soil was determined in the field in southeastern Australia. Wheat and barley cultivars had different effects on the population densities of P. thornei. Most commercial wheat cultivars that are grown in southeastern Australia were susceptible, while the barley cultivars were resistant or moderately resistant. Lentil, field pea, fenugreek, linseed, and medic were found to be resistant to P. thornei, while faba bean and canola were moderately resistant and narbon bean, subterranean clover, and vetch were susceptible. This study will enable growers to select rotational crops to reduce the population densities of these nematodes and therefore minimize the yield loss they cause.
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Society of Nematologists Crop Loss Assessment Committee. Bibliography of Estimated Crop Losses in the United States Due to Plant-parasitic Nematodes. J Nematol 1987; 19:6-12. [PMID: 19290265] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/27/2023] Open
Abstract
Recent published estimates of crop losses due to plant-parasitic nematodes are summarized by crop and state. Estimates are systematically reported from major producing states for cotton, peanut, tobacco, and soybean. Only scattered reports were available for nematode losses to other field crops or to vegetables and ornamentals. Among the states, North Carolina and Michigan were most consistent in reporting loss estimates from the widest range of crops.
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