Nematodes.

2021 ◽  
pp. 270-284
Author(s):  
Regina M. D. G. Carneiro ◽  
Marcilene F. A. Santos ◽  
José Mauro C. Castro
Keyword(s):  
Life Cycle ◽  
Cover Crops ◽  
Control Strategies ◽  
Management Strategies ◽  
Genetic Resistance ◽  
Root Knot Nematodes ◽  
Meloidogyne Enterolobii ◽  
Host Status ◽  
Fruit Plants ◽  
Host Parasite

Abstract The following review of the nematodes from cultivated guava is limited to the major problem caused by M. enterolobii, its idenfication and its management strategies. The synonymization of Meloidogyne enterolobii with Meloidogyne mayaguensis and the different methods of identifying Meloidogyne species are discussed. The life cycle, host-parasite relationships, symptoms, damage and dissemination of M. enterolobii are described. The host status of cover crops, maize and fruit plants for M. enterolobii is discussed, as well as the resistance in Psidium spp. to root-knot nematodes. New prospects using genetic resistance in Brazil and some control strategies that can be used in an integrated way are presented.

Maize and root-knot nematodes: a problematic, deep-seated association.

2021 ◽  
pp. 41-47
Author(s):  
Hendrika Fourie
Keyword(s):  
South Africa ◽  
Life Cycle ◽  
Host Range ◽  
Geographical Distribution ◽  
Meloidogyne Incognita ◽  
Management Strategies ◽  
Economic Importance ◽  
Future Research ◽  
Root Knot Nematodes ◽  
Damage Symptoms

Abstract This paper focuses on the economic importance, host range, geographical distribution, damage symptoms and biology and life cycle of the root knot nematodes Meloidogyne incognita and M. javanica infesting maize in South Africa. Information on their interactions with other nematodes and pathogens, recommended integrated nematode management strategies and future research requirements are also discussed.

Assessment of crop and weed management strategies prior to introduction of auxin-resistant crops in Brazil

2020 ◽  
pp. 1-11
Author(s):  
Maxwel C. Oliveira ◽  
Anelise Lencina ◽  
André R. Ulguim ◽  
Rodrigo Werle
Keyword(s):  
Cover Crops ◽  
Weed Management ◽  
Management Practices ◽  
Cropping Systems ◽  
Control Strategies ◽  
Management Strategies ◽  
Acetolactate Synthase ◽  
Weed Species ◽  
Research Education ◽  
No Till

Abstract A stakeholder survey was conducted from April through June of 2018 to understand stakeholders’ perceptions and challenges about cropping systems and weed management in Brazil. The dominant crops managed by survey respondents were soybean (73%) and corn (66%). Approximately 75% of survey respondents have grown or managed annual cropping systems with two to three crops per year cultivated in succession. Eighteen percent of respondents manage only irrigated cropping systems, and over 60% of respondents adopt no-till as a standard practice. According to respondents, the top five troublesome weed species in Brazilian cropping systems are horseweed (asthmaweed, Canadian horseweed, and tall fleabane), sourgrass, morningglory, goosegrass, and dayflower (Asiatic dayflower and Benghal dayflower). Among the nine species documented to have evolved resistance to glyphosate in Brazil, horseweed and sourgrass were reported as the most concerning weeds. Other than glyphosate, 31% and 78% of respondents, respectively, manage weeds resistant to acetyl-CoA carboxylase (ACCase) inhibitors and/or acetolactate synthase (ALS) inhibitors. Besides herbicides, 45% of respondents use mechanical, and 75% use cultural (e.g., no-till, crop rotation/succession) weed control strategies. Sixty-one percent of survey respondents adopt cover crops to some extent to suppress weeds and improve soil chemical and physical properties. Nearly 60% of survey respondents intend to adopt the crops that are resistant to dicamba or 2,4-D when available. Results may help practitioners, academics, industry, and policy makers to better understand the bad and the good of current cropping systems and weed management practices adopted in Brazil, and to adjust research, education, technologies priorities, and needs moving forward.

Integrated nematode management of root lesion and root-knot nematodes in soybean in Brazil.

2021 ◽  
pp. 103-110
Author(s):  
Pedro Luiz Martins Soares ◽  
Daniel Dalvan Nascimento
Keyword(s):  
Life Cycle ◽  
Host Range ◽  
Geographical Distribution ◽  
Management Strategies ◽  
Meloidogyne Javanica ◽  
Economic Importance ◽  
Future Outlook ◽  
Root Knot Nematodes ◽  
Nematode Management ◽  
Damage Symptoms

Abstract This chapter focuses on the economic importance, host range, geographical distribution, damage symptoms and biology and life cycle of root lesion and root-knot nematodes infesting soyabean in Brazil, i.e. Pratylenchus brachyurus, Meloidogyne javanica and M. incognita. Some information on their interactions with other nematodes and pathogens, efficacy and optimization of some recommended integrated nematode management strategies and future outlook and research requirements for nematode management are also presented.

Chemosensory genes in the head of Spodoptera litura larvae

2021 ◽  
pp. 1-10
Author(s):  
Lu-Lu Li ◽  
Ji-Wei Xu ◽  
Wei-Chen Yao ◽  
Hui-Hui Yang ◽  
Youssef Dewer ◽  
...  
Keyword(s):  
Spodoptera Litura ◽  
Phylogenetic Trees ◽  
Target Genes ◽  
Control Strategies ◽  
Insect Pest ◽  
Management Strategies ◽  
Food Sources ◽  
Larval Feeding ◽  
Chemosensory System ◽  
Chemosensory Genes

Abstract The tobacco cutworm Spodoptera litura (Lepidoptera: Noctuidae) is a polyphagous pest with a highly selective and sensitive chemosensory system involved in complex physiological behaviors such as searching for food sources, feeding, courtship, and oviposition. However, effective management strategies for controlling the insect pest populations under threshold levels are lacking. Therefore, there is an urgent need to formulate eco-friendly pest control strategies based on the disruption of the insect chemosensory system. In this study, we identified 158 putative chemosensory genes based on transcriptomic and genomic data for S. litura, including 45 odorant-binding proteins (OBPs, nine were new), 23 chemosensory proteins (CSPs), 60 odorant receptors (ORs, three were new), and 30 gustatory receptors (GRs, three were new), a number higher than those reported by previous transcriptome studies. Subsequently, we constructed phylogenetic trees based on these genes in moths and analyzed the dynamic expression of various genes in head capsules across larval instars using quantitative real-time polymerase chain reaction. Nine genes–SlitOBP8, SlitOBP9, SlitOBP25, SlitCSP1, SlitCSP7, SlitCSP18, SlitOR34, SlitGR240, and SlitGR242–were highly expressed in the heads of 3- to 5-day-old S. litura larvae. The genes differentially expressed in olfactory organs during larval development might play crucial roles in the chemosensory system of S. litura larvae. Our findings substantially expand the gene inventory for S. litura and present potential target genes for further studies on larval feeding in S. litura.

scholarly journals Occurrence, Impact on Agriculture, Human Health, and Management Strategies of Zearalenone in Food and Feed: A Review

Toxins ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 92
Author(s):  
Dipendra Kumar Mahato ◽  
Sheetal Devi ◽  
Shikha Pandhi ◽  
Bharti Sharma ◽  
Kamlesh Kumar Maurya ◽  
...  
Keyword(s):  
Human Health ◽  
Control Strategies ◽  
Management Strategies ◽  
Structural Similarity ◽  
Fungal Metabolites ◽  
Natural Estrogens ◽  
Food And Feed ◽  
Feed Safety ◽  
And Control ◽  
Different Sources

Mycotoxins represent an assorted range of secondary fungal metabolites that extensively occur in numerous food and feed ingredients at any stage during pre- and post-harvest conditions. Zearalenone (ZEN), a mycotoxin categorized as a xenoestrogen poses structural similarity with natural estrogens that enables its binding to the estrogen receptors leading to hormonal misbalance and numerous reproductive diseases. ZEN is mainly found in crops belonging to temperate regions, primarily in maize and other cereal crops that form an important part of various food and feed. Because of the significant adverse effects of ZEN on both human and animal, there is an alarming need for effective detection, mitigation, and management strategies to assure food and feed safety and security. The present review tends to provide an updated overview of the different sources, occurrence and biosynthetic mechanisms of ZEN in various food and feed. It also provides insight to its harmful effects on human health and agriculture along with its effective detection, management, and control strategies.

Research Advances in Potyviruses: From the Laboratory Bench to the Field

2021 ◽  
Vol 59 (1) ◽  
Author(s):  
Xiuling Yang ◽  
Yinzi Li ◽  
Aiming Wang
Keyword(s):  
Control Strategies ◽  
Genetic Resistance ◽  
Plant Viruses ◽  
Infection Process ◽  
Future Research ◽  
Annual Review ◽  
Publication Date ◽  
Viral Pathogens ◽  
Genome Expression ◽  
Amount Of Knowledge

Potyviruses (viruses in the genus Potyvirus, family Potyviridae) constitute the largest group of known plant-infecting RNA viruses and include many agriculturally important viruses that cause devastating epidemics and significant yield losses in many crops worldwide. Several potyviruses are recognized as the most economically important viral pathogens. Therefore, potyviruses are more studied than other groups of plant viruses. In the past decade, a large amount of knowledge has been generated to better understand potyviruses and their infection process. In this review, we list the top 10 economically important potyviruses and present a brief profile of each. We highlight recent exciting findings on the novel genome expression strategy and the biological functions of potyviral proteins and discuss recent advances in molecular plant–potyvirus interactions, particularly regarding the coevolutionary arms race. Finally, we summarize current disease control strategies, with a focus on biotechnology-based genetic resistance, and point out future research directions. Expected final online publication date for the Annual Review of Phytopathology, Volume 59 is August 2021. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

Host suitability of summer cover crops to Meloidogyne arenaria, M. enterolobii, M. incognita and M. javanica

Nematology ◽  
2021 ◽  
pp. 1-9
Author(s):  
Hung X. Bui ◽  
Johan A. Desaeger
Keyword(s):  
Cover Crops ◽  
Nematode Species ◽  
Host Suitability ◽  
Parasitic Nematodes ◽  
Plant Parasitic Nematodes ◽  
Root Knot Nematode ◽  
Sunn Hemp ◽  
Host Status ◽  
Susceptible Control ◽  
Sorghum Sudangrass

Summary Cover crops can be a useful tool for managing plant-parasitic nematodes provided they are poor or non-hosts for the target nematode species. A glasshouse experiment was done to determine the host status of four common cover crops in Florida, sunn hemp, cowpea, sorghum sudangrass and sunflower, to pure populations of four common tropical root-knot nematode (RKN) species Meloidogyne javanica (Mj), M. incognita (Mi), M. enterolobii (Me) and M. arenaria (Ma). Tomato was included as a susceptible control. Eight weeks after nematode inoculation (WAI), tomato showed the highest root gall damage for all tested RKN species, with gall indices (GI) between 7 (Ma) and 8.5 (Me) and reproduction factor (RF) ranging from 20 (Ma) to 50 (Mj). No visible root galls were observed for any of the RKN species on sunn hemp and sorghum sudangrass at 8 WAI. However, Mj and Mi were able to reproduce slightly on sorghum sudangrass (RF = 0.02 and 0.79, respectively). Sunflower and cowpea were infected by all four tested RKN species, but host suitability varied. Sunflower root galling ranged from 1.1 (Me) to 4.5 (Mj) and RF = 3.2 (Me) to 28.7 (Mj), while cowpea root galling ranged from 0.6 (Mi) to 5.1 (Me) and RF = 0.8 (Mi) to 67.3 (Mj). Sunn hemp and, to a lesser extent, sorghum sudangrass were poor hosts to all four tested RKN species. Sunflower was a good host to all RKN species, but root gall damage and RF were lowest for Me. Cowpea was a good host to Mj, Me and Ma, but a poor host to Mi. Our results confirm and stress the importance of RKN species identification when selecting cover crops as an RKN management strategy.

Life Cycle Cost Management Strategy on Corrosion Deterioration and Fatigue Damage of Steel Girder Bridge

2008 ◽  
Vol 385-387 ◽  
pp. 845-848
Author(s):  
Moe M.S. Cheung ◽  
Kevin K.L. So ◽  
Xue Qing Zhang
Keyword(s):  
Life Cycle ◽  
Fatigue Damage ◽  
Life Cycle Cost ◽  
Management Strategies ◽  
Maintenance Cost ◽  
Steel Girder ◽  
Damage Models ◽  
Failure Cost ◽  
Steel Girder Bridge ◽  
Girder Bridge

This paper proposes a life-cycle cost (LCC) management methodology that integrates corrosion deterioration and fatigue damage mechanisms. This LCC management methodology has four characterized features: (1) corrosion deterioration and fatigue damage models are used to predict the time when the pre-defined limits are reached; (2) the performance of the steel girder is measured by condition state sets in which deflection, moment and shear capacities and fatigue strength limits are considered altogether; (3) the cost-effectiveness of management strategies are measured by the performance improvement per unit of money spent; and (4) the LCC model includes initial design/construction cost, inspection cost, maintenance cost, repair/rehabilitation cost and failure cost. A steel girder bridge is used as an example to demonstrate the application of the proposed LCC management methodology.

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