Maize Head Smut: Pathogenesis, Epidemiology, and Management Options

2020 ◽  
Vol 2 (1) ◽  
pp. 63-71
Author(s):  
Philip Chemeltorit ◽  
◽  
Suresh L. M. ◽  
Keyword(s):  
Major Quantitative Trait Locus ◽  
Review Paper ◽  
Effective Management ◽  
Security Threat ◽  
Head Smut ◽  
Management Options ◽  
Seed Certification ◽  
Stages Of Growth ◽  
Worldwide Distribution ◽  
Trait Locus

Maize (Zea mays) head smut caused by Sphacelotheca reiliana, a basidiomycete with worldwide distribution, can cause devastating crop losses that pose a food security threat. While Kenya has experienced high incidences of the disease in the recent years, the seed certification regulation has a zero tolerance on S. reiliana. The spores of S. reiliana remain viable in soil for many years and serve as the main inoculum source as they germinate when the conditions are favourable and infect the host in the early stages of growth after germination. After penetration, the fungus grows systemically as the plant matures eventually transforming part or all of the inflorescence (ears and tassels) tissues into smut galls. The symptoms develop because the inflorescences have increased levels of reactive oxygen species, auxin, and misregulation of floral regulatory transcription factors. The most practical control strategy for maize head smut encompasses the use of resistant/tolerant cultivars, fungicide treatment (of seed or drenching of rows immediately after seeding), and field hygiene/ sanitation. Crop rotation may help when host crops are not planted for between 2-3 years or even more. Resistance genes, including ZmWAK, found in the major quantitative trait locus qHSR1/qHS2.09 regulate resistance of maize to head smut. The objective of this review paper is to provide an understanding of the head smut disease pathogenesis, epidemiology, and effective management options. Key words: Sphacelotheca reiliana, basidiomycete, seed certification, smut galls, resistance gene

scholarly journals Coexisting ecosystem states in a tropical coastal lagoon under progressive eutrophication in the northern Cuban keys

2018 ◽  
Vol 82 (3) ◽  
pp. 139 ◽  
Author(s):  
Roberto González-De Zayas ◽  
Martin Merino-Ibarra ◽  
Patricia M. Valdespino-Castillo ◽  
Yunier Olivera ◽  
Sergio F. Castillo-Sandoval
Keyword(s):  
Residence Time ◽  
Coastal Lagoon ◽  
Spatial And Temporal Variability ◽  
Positive Trend ◽  
Water Residence Time ◽  
Effective Management ◽  
Management Options ◽  
Trophic Index ◽  
Tropical Coastal Lagoon ◽  
Mollusc Assemblages

Through a nested suite of methods here we contrast the coexistence of different ecosystem states in a tropical coastal lagoon, the Laguna Larga, with increasing eutrophication stress between 2007 and 2009. Water temperature averaged 27.4°C in the lagoon and showed a slight positive trend during the study period. Salinity averaged 35.0±6.2, exhibiting high spatial and temporal variability, and also a slight positive trend in time. In contrast, dissolved oxygen showed a substantial decreasing trend (–0.83 ml L–1 y–1; –13.3% y–1) over the period, while nutrients increased dramatically, particularly total phosphorus (2.6 µM y–1), in both cases sustaining the progression of eutrophication in the lagoon during the three years we sampled. The Karydis nutrient load-based trophic index showed that the lagoon has a spatial pattern of increasing eutrophication from the sea and the outer sector (oligotrophic-mesotrophic) to the central (mesotrophic) and the inner sector (mesotrophic-eutrophic). Two ecosystem states were found within the lagoon. In the outer oligotrophic sector, the dominant primary producers were macroalgae, seagrasses and benthic diatoms, while mollusc assemblages were highly diverse. In the inner and central sectors (where trophic status increased toward the inner lagoon) a phytoplankton-dominated ecosystem was found where mollusc assemblages are less diverse. In spite of the progression of eutrophication in the lagoon, these two different ecosystems coexisted and remained unchanged during the study period. Apparently, the effect of water residence time, which increases dramatically toward the inner lagoon, dominated over that of nutrient loadings, which is relatively more homogeneously distributed along the lagoon. Therefore, we consider that actions that reduce the water residence time are likely the most effective management options for this and other similarly choked lagoons.

scholarly journals Root-knot nematode (Meloidogyne incognita) and its management: a review

2020 ◽  
Vol 3 (2) ◽  
pp. 21-31
Author(s):  
Sudeep Subedi ◽  
Bihani Thapa ◽  
Jiban Shrestha
Keyword(s):  
Meloidogyne Incognita ◽  
Host Cells ◽  
Effective Management ◽  
Root Knot Nematode ◽  
Biotic And Abiotic Stresses ◽  
Management Options ◽  
Feeding Site ◽  
Second Stage ◽  
Stage Juvenile ◽  
Growth Quality

Root-knot nematode (RKN) Meloidogyne incognita stands out among the most harmful polyphagous endoparasite causing serious harm to plants, and distributed all over the globe. RKN causes reduced growth, quality and yield along with reduced resistance of the host against biotic and abiotic stresses. Infective second stage juvenile enters host roots with the help of the stylet and becomes sedentary getting into the vascular cylinder. Dramatic changes occur in host cells, making a specialized feeding site, induced by the secretion of effector protein by RKN. M. incognita can be controlled by nematicides, biocontrol agents, botanicals essential oils and growing resistant cultivars. Nematicides are no longer allowed to use in many parts of the world because of environmental hazards and toxicity to humans and other organisms. Researchers are concentrating on searching suitable alternatives to nematicides for effective management of M. incognita. This review mainly tries to explain the biology of M. incognita and different management options recommended in recent years. However, an effective and economical management of M. incognita remains an immense challenge.

scholarly journals Identification of A Major Quantitative Trait Locus for Grain Weight In Rice Using Microsatellite Marker

2017 ◽  
Vol 21 (4) ◽  
Author(s):  
Mariana Susilowati ◽  
Hajrial Aswidinnoor ◽  
Wening Enggarini ◽  
Kurniawan Rudi Trijatmiko
Keyword(s):  
Quantitative Trait Locus ◽  
Microsatellite Marker ◽  
Quantitative Trait ◽  
Major Quantitative Trait Locus ◽  
Grain Weight ◽  
Trait Locus

Direct and residual contact toxicity of insecticides toHalyomorpha halys(Hemiptera: Pentatomidae)

2019 ◽  
Vol 151 (2) ◽  
pp. 209-218 ◽  
Author(s):  
A.E. Gradish ◽  
H. Fraser ◽  
C.D. Scott-Dupree
Keyword(s):  
United States Of America ◽  
Economic Loss ◽  
The United States ◽  
Invasive Pest ◽  
Contact Toxicity ◽  
Halyomorpha Halys ◽  
Effective Management ◽  
Management Options ◽  
Horticultural Crops ◽  
Contact Exposure

AbstractHalyomorpha halys(Stål) (Hemiptera: Pentatomidae) is a serious invasive pest of many agricultural and horticultural crops in Canada and the United States of America. To mitigate economic loss for growers, effective management options forH. halysare needed. We evaluated the efficacy of 12 insecticides (Beauveria bassiana(Balsamo-Crivelli) Vuillemin (Cordycipitaceae), boric acid, chlorpyrifos, clothianidin, flupryadifurone, λ-cyhalothrin, malathion, novaluron, sulfoxaflor, thiamethoxam, thiamethoxam + λ-cyhalothrin, and thiamethoxam + novaluron) currently used or with potential forH. halysmanagement by determining their direct and residual contact toxicity toH. halysnymphs. Each insecticide was tested at its Canadian label rate and half and twice that rate. With the exception of chlorpyrifos, nymph mortality was low (< 40%) following direct or residual contact exposure to all insecticides and rates. All surviving nymphs were severely affected (i.e., knocked down) by direct and residual contact exposure to neonicotinoids, while approximately 66% of nymphs were severely affected following exposure to sulfloxaflor residues at label and twice label rate. However, few nymphs were severely affected by all other insecticides and rates. Overall, our results suggest thatH. halysis not susceptible to many insecticides at current label rates for Canada. More research is needed to identify efficacious insecticides forH. halys.

Mapping and validation of a major quantitative trait locus qRN5a associated with increasing root number under low potassium in rice

2020 ◽  
Vol 90 (3) ◽  
pp. 519-528 ◽  
Author(s):  
Anowerul Islam ◽  
Yingxin Zhang ◽  
Galal Anis ◽  
M. H. Rani ◽  
Workie Anley ◽  
...  
Keyword(s):  
Quantitative Trait Locus ◽  
Quantitative Trait ◽  
Major Quantitative Trait Locus ◽  
Root Number ◽  
Low Potassium ◽  
Trait Locus

scholarly journals Zanamivir: from drug design to the clinic

2001 ◽  
Vol 356 (1416) ◽  
pp. 1885-1893 ◽  
Author(s):  
Michael Elliott
Keyword(s):  
Clinical Trials ◽  
Antiviral Activity ◽  
Respiratory Tract ◽  
Early Treatment ◽  
Neuraminidase Inhibitors ◽  
Effective Management ◽  
Management Options ◽  
Influenza Illness ◽  
Clinically Significant ◽  
Complementary Strategy

The development of the neuraminidase inhibitors has revolutionized the management options for influenza. Zanamivir was the first such inhibitor to be approved for the treatment of influenza in humans. It is delivered by inhalation to the respiratory tract, which is the site of viral replication, in order to ensure immediate antiviral activity. Early treatment with zanamivir in clinical trials rapidly reduced the severity and duration of influenza symptoms and associated complications. Furthermore, chemoprophylaxis with zanamivir was shown to be effective in the prevention of influenza illness. To date, there is no evidence for the emergence of clinically significant zanamivir–resistant isolates. In conclusion, zanamivir offers a useful complementary strategy to vaccination in the effective management of influenza.

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