scholarly journals Geostatistical Analysis of the Spatiotemporal Dynamics of Powdery Mildew and Leaf Rust in Wheat

2009 ◽  
Vol 99 (8) ◽  
pp. 974-984 ◽  
Author(s):  
Jonas Franke ◽  
Steffen Gebhardt ◽  
Gunter Menz ◽  
Hans-Peter Helfrich

Plant diseases are dynamic systems that progress or regress in spatial and temporal dimensions. Site-specific or temporally optimized disease control requires profound knowledge about the development of each stressor. The spatiotemporal dynamics of leaf rust (Puccinia recondite f. sp. tritici) and powdery mildew (Blumeria graminis f. sp. tritici) in wheat was analyzed in order to evaluate typical species-dependent characteristics of disease spread. During two growing seasons, severity data and other relevant plant growth parameters were collected in wheat fields. Spatial characteristics of both diseases were assessed by cluster analyses using spatial analysis by distance indices, whereas the temporal epidemic trends were assessed using statistical parameters. Multivariate statistics were used to identify parameters suitable for characterizing disease trends into four classes of temporal dynamics. The results of the spatial analysis showed that both diseases generally occurred in patches but a differentiation between the diseases by their spatial patterns and spread was not possible. In contrast, temporal characteristics allowed for a differentiation of the diseases, due to the fact that a typical trend was found for leaf rust which differed from the trend of powdery mildew. Therefore, these trends suggested a high potential for temporally optimized disease control. Precise powdery mildew control would be more complicated due to the observed high variability in spatial and temporal dynamics. The general results suggest that, in spite of the high variability in spatiotemporal dynamics, disease control that is optimized in space and time is generally possible but requires consideration of disease- and case-dependent characteristics.

2021 ◽  
Vol 1 (25) ◽  
pp. 50-63
Author(s):  
G.V. Volkova ◽  
◽  
A.V. Danilova ◽  
L.N. Shulyakovskaya ◽  
A.V. Minakova ◽  
...  

Phytosanitary monitoring is the most important element of integrated plant protection. It is used to identify the state of crops, the spread of diseases, the degree of their damage, and also to plan the protective measures. The aim of the research was to assess the development of the most dangerous diseases on winter barley crops in the Krasnodar Krai and the Republic of Adygea (alternate spelling: Adygeya) in the pre-harvest period in 2017–2019 (late May-beginning of June, late milk-early dough stage of development (Z 70-75)). The analysis of the three-year dynamics of pathogens development on winter barley was carried out. The obtained data were compared with the agro-climatic conditions of the growing seasons. Phytosanitary and agroecological observations were carried out according to generally accepted methods and techniques. In the agricultural season 2016–2017, the weather in autumn was warm; winter was mild and snowless; spring was early with an unstable temperature regime and significant lack of precipitation. Warm and dry autumn, snowless winter with long thaws, spring with temperature changes were observed during the growing season of 2017–2018. Autumn in the 2018–2019 vegetative season was cool. Winter was mild and snowless. Sharp changes in air temperature were observed in spring. There was a shortage of precipitation, however, heavy precipitation was noted later. Spot blotch of barley (Cochliobolus sativus (S. Ito & Kuribayashi) Drechs.), barley net blotch (Pyrenophora teres Drechsler.), powdery mildew of barley (Blumeria graminis (DC.) Speer) and leaf rust of barley (Puccinia hordei G. H. Otth.) were detected in the pathogenic complex of the crop. Different types of leaf spots of barley dominated among the detected plant diseases. Intensive development of spot blotch was observed on winter barley crops in Kurganinsky (47.9 %), Dinsky (30.0 %), Novokubansky (28.3 %) and Vyselkovsky (26.3 %) districts, as well as in the Maykop district of the Republic of Adygea (28.3 %). Significant development of barley net blotch was recorded in Kushchevsky (33.5 %), Dinsky (30.8 %) and Novokubansky (29.2 %) districts. The level of powdery mildew development was low (up to 1 %) in all regions. Just a few cases of leaf rust of barley during three years of research were noted. The results of phytosanitary monitoring are presented in the form of electronic maps of the spread of winter barley diseases in the regions of the Krasnodar Krai and the Republic of Adygea.


Author(s):  
Ekaterina Maksimova ◽  
Ekaterina Maksimova ◽  
Vladimir Zhigulsky ◽  
Vladimir Zhigulsky ◽  
Vladimir Shuisky ◽  
...  

The macrophyte thicket ecosystems of higher aquatic vegetation in the Neva Bay (NB) and Eastern Gulf of Finland (EGoF) perform many important roles, including acting as the habitats, nesting sites and migration sites for aquatic and semi-aquatic birds, creating the specific conditions necessary for the spawning and growth of many species of fish, and taking part in the self-purification of the aquatic ecosystems. Many anthropogenic disturbances, hydraulic works in particular, have a significant negative impact on these macrophyte thicket ecosystems. In recent years, the active growth of a new type of macrophyte thicket has been observed in the NB. This is due to the aftereffects of the construction of the Saint Petersburg Flood Prevention Facility Complex (FPFC). It is quite likely that the total macrophyte thicket area in these waters is currently increasing. In the future, it will be necessary to assess the environmental impacts of the hydraulic works on the macrophyte thicket of the NB and EGoF, taking into account the background processes of the spatiotemporal dynamics of the reed beds in the waters in question. To do this, it will be necessary to carry out a comprehensive study of these ecosystems and identify patterns in their spatial and temporal dynamics. The program of the study has been developed and is currently being implemented by Eco-Express-Service, a St. Petersburg eco-design company.


2021 ◽  
Vol 11 (5) ◽  
pp. 2282
Author(s):  
Masudulla Khan ◽  
Azhar U. Khan ◽  
Mohd Abul Hasan ◽  
Krishna Kumar Yadav ◽  
Marina M. C. Pinto ◽  
...  

In the present era, the global need for food is increasing rapidly; nanomaterials are a useful tool for improving crop production and yield. The application of nanomaterials can improve plant growth parameters. Biotic stress is induced by many microbes in crops and causes disease and high yield loss. Every year, approximately 20–40% of crop yield is lost due to plant diseases caused by various pests and pathogens. Current plant disease or biotic stress management mainly relies on toxic fungicides and pesticides that are potentially harmful to the environment. Nanotechnology emerged as an alternative for the sustainable and eco-friendly management of biotic stress induced by pests and pathogens on crops. In this review article, we assess the role and impact of different nanoparticles in plant disease management, and this review explores the direction in which nanoparticles can be utilized for improving plant growth and crop yield.


Author(s):  
Ibrahim Sobhy Draz ◽  
Ahmed Fawzy Elkot ◽  
Abdelrazek Shaarawy Abdelrhim
Keyword(s):  

2004 ◽  
Vol 84 (4) ◽  
pp. 1015-1023 ◽  
Author(s):  
H. J. Li ◽  
R. L. Conner ◽  
B. D. McCallum ◽  
X. M. Chen ◽  
H. Su ◽  
...  

The hard red winter wheat Tangmai 4 did not develop symptoms of infection following inoculation with powdery mildew (Erysiphe graminis DC. f. sp. tritici E. Marchal) isolates from regions of western Canada and northern China. Tangmai 4 exhibited resistance to stem rust (Puccinia graminis Pers. f. sp. tritici Eriks. & Henn.) and leaf rust (P. triticina Eriks.) races from western Canada. This wheat line was resistant to individual stripe rust (P. striiformis Westend. f. sp. tritici Eriks.) races from the U.S. and Canada. Sequential C-banding and genomic in situ hybridization (GISH), and electrophoretic analyses of high molecular weight glutenins and gliadins demonstrated that Tangmai 4 carried a pair of T1BL·1RS wheat-rye (Secale cereale L.) translocated chromosomes. Since the genes located on T1BL·1RS are no longer effective in controlling powdery mildew and the rust diseases, Tangmai 4 must carry additional genes for resistance to these diseases, which makes it a valuable resource for the improvement of resistance in wheat against these diseases. Key words: T1BL·1RS translocation, disease resistance, sequential C-banding and GISH, glutenin, gliadin


PROTOPLASMA ◽  
2014 ◽  
Vol 252 (4) ◽  
pp. 1167-1179 ◽  
Author(s):  
Yulin Cheng ◽  
Juanni Yao ◽  
Hongchang Zhang ◽  
Lili Huang ◽  
Zhensheng Kang

2013 ◽  
Vol 2013 ◽  
pp. 1-10 ◽  
Author(s):  
Meenakshi Thakur ◽  
Baldev Singh Sohal

Disease control is largely based on the use of fungicides, bactericides, and insecticides—chemical compounds toxic to plant invaders, causative agents, or vectors of plant diseases. However, the hazardous effect of these chemicals or their degradation products on the environment and human health strongly necessitates the search for new, harmless means of disease control. There must be some natural phenomenon of induced resistance to protect plants from disease. Elicitors are compounds, which activate chemical defense in plants. Various biosynthetic pathways are activated in treated plants depending on the compound used. Commonly tested chemical elicitors are salicylic acid, methyl salicylate, benzothiadiazole, benzoic acid, chitosan, and so forth which affect production of phenolic compounds and activation of various defense-related enzymes in plants. Their introduction into agricultural practice could minimize the scope of chemical control, thus contributing to the development of sustainable agriculture. This paper chiefly highlights the uses of elicitors aiming to draw sufficient attention of researchers to the frontier research needed in this context.


Plant Disease ◽  
1999 ◽  
Vol 83 (7) ◽  
pp. 694-694 ◽  
Author(s):  
P. L. Sholberg ◽  
J. H. Ginns ◽  
T. S. C. Li

Purple coneflowers (Echinacea purpurea) are grown in North America and Europe for their medicinal properties and as ornamental plants. In September 1997 and again in 1998, a previously undescribed disease was noticed on fully grown coneflower plants in Summerland and Oliver, British Columbia. Mycelia were observed on stems, foliage, and flowers, and distinct dark red to black, round (approximately 5 mm in diameter) lesions were observed on the flower petals. The disease appeared similar to powdery mildews that have been reported on numerous genera of the Asteraceae. Samples of the diseased tissue were examined and the salient features of the fungus on two specimens were determined: cleistothecia infrequent, subglobose or flattened on the side next to the leaf surface, 121 to 209 μm in diameter; epidermal (surface) cells 20 μm in diameter; appendages hyphoid, 5 μm in diameter, up to 200 μm long; asci, 10 to 19 in each cleistothecium, broadly ellipsoid, 47 to 85 × 28 to 37 μm with a short stalk, about 8 to 13 μm long and 8 μm in diameter; ascospores, immature, two per ascus, ellipsoid to broadly ellipsoid, 17 to 25 × 11 to 13 μm, thin walled, hyaline, and smooth; conidia oblong with sides slightly convex and apices truncate, 27 to 40 × 14 to 20 μm, walls hyaline, thin, smooth. Based on the occurrence of asci that contained two ascospores and the hyphoid appendages on the cleistothecia we concluded that the fungus was Erysiphe cichoracearum DC. Damage due to this disease was minimal in 1997 and 1998 because it developed very late in the growing season and occurred sporadically within the plantings. In order to complete Koch's postulates, Echinacea purpurea plants grown in the greenhouse were inoculated with a conidial suspension (105 to 106 conidia per ml) from field-infected plants. Powdery mildew first appeared 3 months later, eventually infecting leaves and stems of 12 of 49 inoculated plants. It was distinctly white and in discrete patches on leaves, compared with coalescing dark brown areas on the stems. Microscopic examination of the conidia confirmed that they were E. cichoracearum. Although powdery mildew caused by E. cichoracearum has been widely reported on lettuce, safflower, and other cultivated and wild Compositae, we found no reference to it on Echinacea spp. in Canada (1,2), the U.S. (3), or elsewhere in the world (4). The specimens have been deposited in the National Mycological Herbarium of Canada (DAOM) with accession numbers 225933 and 225934 for Oliver and Summerland, B.C., respectively. References: (1) U. Braun. Beih. Nova Hedwigia 89:1, 1987. (2) I. L. Conners. 1967. An annotated index of plant diseases in Canada and fungi recorded on plants in Alaska, Canada, and Greenland. Canada Dept. of Agric. Pub. 1251. (3) D. F. Farr et al. 1989. Fungi on Plants and Plant Products in the United States. American Phytopathological Society, St. Paul, MN. (4) J. Ginns. 1986. Compendium of plant disease and decay fungi in Canada, 1960-1980. Agriculture Canada Pub. 1813.


Author(s):  
Tatyana Yuryevna Taranova ◽  
Alexander Ivanovich Kincharov ◽  
Elena Anatolyevna Demina ◽  
Olga Sergeevna Mullayanova

For breeding to create varieties resistant to fungal diseases, it is effective to work in the search for new genes of resistance to pathogens, as well as to constantly update the gene pool of spring wheat. The researches were conducted in 2014-2019 in the Samara region. The object of study was 352 collection samples of spring soft wheat of various ecological and geographical groups. The assessment of samples for resistance to fungal pathogens was carried out against a natural infectious background, including in years with a strong development of certain diseases (powdery mildew – 2014, brown rust – 2016, 2017). Accounting of plant damage by fungal diseases was carried out according to generally accepted phytopathological methods. Since 2000, the laboratory has studied and developed more than one thousand collection samples, formed working characteristic collections of samples for resistance to leaf rust (142), powdery mildew (185) and with complex resistance to these diseases (100). According to the results of six-year studies, collection samples with complex resistance to leaf rust and powdery mildew were identified: Kinelskaya yubileynaya, Erythrospermum 4112, Erythrospermum 4143, Erythrospermum 4144, Erythrospermum 4146, Erythrospermum 4147, Lutescens 6045/7, Erythrospermum 6310/10-63 (Kinel), Khutoryanka (Tambov), Ulyanovskaya 105, Yaritsa (Ulyanovsk), Tulaykovskaya 108 (Bezenchuk), Sigma 2 (Omsk), KVS Aquilon (Germany). Relatively resistant to root rot pathogens samples were noted: Kinelskaya 2010, Lutescens 3960, Erythrospermum 4112, Erythrospermum 4171, Lutescens 4394 (Kinel). The selected varieties and breeding lines are recommended by us as sources of resistance to fungal diseases for use in breeding programs of the middle Volga region and research sites with similar agro-climatic conditions.


2009 ◽  
Vol 15 (1-2) ◽  
Author(s):  
I. J. Holb

In this review, some important features of biology and epidemiology are summarised for apple powdery mildew (Podosphaera leucotricha). In the first part of the review, the geographical distribution or the pathogen are discussed, then the morphology and taxonomy of the causal organism are described. Disease symptoms or apple powdery mildew are also shown and then host susceptibility/resistance is discussed in relation to durability of resistance. In the second part of this review, the general disease cycle of powdery mildew on apple are demonstrated and some basic features of powdery mildew epidemiology (such response of the pathogen to temperature, relative humidity, and rain as well as spore production, spore dispersal, diurnal patterns and temporal dynamics of the pathogen/disease) are also given on apple host.


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