scholarly journals Significance of Sexual Reproduction of Phytophthora infestans in the Czech Republic

2018 ◽  
Vol 66 (5) ◽  
pp. 1191-1197
Author(s):  
Jana Mazáková ◽  
Miloslav Zouhar ◽  
Pavel Ryšánek
Keyword(s):  
Czech Republic ◽  
Late Blight ◽  
Sexual Reproduction ◽  
Phytophthora Infestans ◽  
Growing Season ◽  
Field Conditions ◽  
Effect Of Temperature ◽  
Mating Types ◽  
The Czech Republic ◽  
Leaf Discs

A total of 187 naturally late blight‑diseased potato leaves were sampled from 31 sites and five regions of the Czech Republic during the growing season in 2012–2014 and 2016 and examined microscopically for the ability of Phytophthora infestans to produce oospores in infected leaves under field conditions. Although the occurrence of the A1 and A2 mating types required for sexual reproduction of P. infestans was previously confirmed in the Czech Republic, no oospores were detected in this study. To study the effect of temperature on the survival of oospores produced from crosses of three pairs of P. infestans isolates, oospores in leaf discs and agar were exposed to temperatures ranging from –24 to 10 °C and then evaluated for viability with the plasmolysis test. Oospore viability ranged from 13.02 to 63.90 % and from 7.77 to 63.37 % for oospores produced in agar and leaf discs, respectively, with the highest frequencies of viable oospores occurring at 4 and 10 °C. To determine whether oospores may survive under field conditions, agar plates with oospores were buried in soil in Prague‑Suchdol and Svitavy for seven months during the overwintering period (October–May) in 2011–2015. There were statistically significant differences in oospore viability examined by the plasmolysis test between the localities, and oospore viability ranged from 29 to 43 % and from 15 to 44 % in Prague‑Suchdol and Svitavy, respectively.

scholarly journals Occurrence and distribution of mating types A1 and A2 of Phytophthora infestans (Mont.) de Bary in the Czech Republic

2010 ◽  
Vol 42 (No. 2) ◽  
pp. 41-48 ◽  
Author(s):  
J. Mazáková ◽  
V. Táborský ◽  
M. Zouhar ◽  
P. Ryšánek ◽  
E. Hausvater ◽  
...  
Keyword(s):  
Czech Republic ◽  
Phytophthora Infestans ◽  
Mating Type ◽  
Mating Types ◽  
Pcr Markers ◽  
The Czech Republic ◽  
First Report

A total of 199 <i>Phytophthora infestans</i> isolates were obtained from leaves, tubers and fruits of infected crops of potato and tomato in different regions of the Czech Republic in 2003, 2004 and 2005. They were analysed for mating type using the conventional pairing assay and PCR markers; 107 isolates were of A1 and 92 of A2 mating type. No self-fertile isolate was found. Our study is the first report of the presence and distribution of the A2 mating type of <i>P. infestans</i> in the Czech Republic. The co-existence of the two mating types may enable the pathogen to reproduce sexually, thus enhancing the diversity of its population countrywide.

scholarly journals Genetic Structure of the Phytophthora infestans Population in Morocco

Plant Disease ◽  
2000 ◽  
Vol 84 (2) ◽  
pp. 173-176 ◽  
Author(s):  
M. Sedegui ◽  
R. B. Carroll ◽  
A. L. Morehart ◽  
T. A. Evans ◽  
S. H. Kim ◽  
...  
Keyword(s):  
Genetic Structure ◽  
Late Blight ◽  
Sexual Reproduction ◽  
Phytophthora Infestans ◽  
Mating Type ◽  
Potato Seed ◽  
Mating Types ◽  
Potato Field ◽  
New Genotype

ABSRACT In 1996 to 1998, a late-blight survey was conducted in potato- and tomato-growing regions of Morocco. A total of 149 isolates of Phytophthora infestans were collected and analyzed for the glucose-6-phosphate isomerase (Gpi) and peptidase (Pep) alleles, mating types, and metalaxyl sensitivities. Four genotypes were identified: MO-1 (mating type A1, Gpi 100/100, Pep 92/100), MO-2 (mating type A1, Gpi 86/100, Pep 92/100), MO-3 (mating type A2 Gpi 100/100, Pep 100/100), and MO-4 (mating type A1, Gpi 100/100, Pep 100/100). The potato isolates were MO-1 (1996 & 97), MO-3 (1998), and MO-4 (1998). The frequencies of A1 (MO-4) and A2 (MO-3) mating types in potato fields in 1998 were 26 and 74%, respectively. Potato isolates were pathogenic to both potatoes and tomatoes. The isolates collected from tomatoes in 1997 and 1998 were MO-2. Potato and tomato isolates were insensitive and sensitive to metalaxyl, respectively. The change of genotype population in 1998 was probably caused by migration of a new genotype from Europe associated with importation of potato seed. The detection of A1 and A2 mating types in the same potato field indicates the potential for sexual reproduction of P. infestans in Morocco.

scholarly journals Mating type distribution of Phytophthora infestans (Mont.) de Bary in the Czech Republic in 2007 and 2008

2010 ◽  
Vol 46 (No. 3) ◽  
pp. 89-97 ◽  
Author(s):  
J. Mazáková ◽  
M. Zouhar ◽  
P. Ryšánek ◽  
V. Táborský ◽  
E. Hausvater ◽  
...  
Keyword(s):  
Czech Republic ◽  
Late Blight ◽  
Phytophthora Infestans ◽  
Mating Type ◽  
Caps Marker ◽  
The Czech Republic ◽  
Type Distribution ◽  
Pcr Assays

A total of 195 isolates of Phytophthora infestans were collected from late blight-diseased potatoes grown in several localities in the Czech Republic during the years 2007&ndash;2008. The isolates were analysed for mating type using the pairing test, CAPS marker assays and PCR assays. Of the 195 tested isolates, 28% were of the A1 mating type and 75% corresponded to the A2 mating type. Furthermore, oospores of P. infestans were microscopically detected in leaf samples from one locality.

scholarly journals The Impact of Climate Change on the Sugar Content of Grapes and the Sustainability of their Production in the Czech Republic

2020 ◽  
Vol 13 (1) ◽  
pp. 222
Author(s):  
Miroslava Navrátilová ◽  
Markéta Beranová ◽  
Lucie Severová ◽  
Karel Šrédl ◽  
Roman Svoboda ◽  
...  
Keyword(s):  
Climate Change ◽  
Czech Republic ◽  
Sugar Content ◽  
Growing Season ◽  
Vegetation Period ◽  
The Czech Republic ◽  
Impact Of Climate Change ◽  
Secondary Sources ◽  
The Impact ◽  
Growing Region

The aim of the presented article is to evaluate the impact of climate change on the sugar content of grapes in the Czech Republic during the period 2000–2019 through selected indicators on the basis of available secondary sources. Attention is focused on the developments in both the main wine-growing regions of Moravia and Bohemia. In the field of viticulture and wine-growing, the sugar content of grapes, as a basic parameter for the classification of wines, plays an important role. In the Czech Republic, the average sugar content of grapes has had a constantly growing trend. This trend is evident both in the wine-growing region of Bohemia and in the wine-growing region of Moravia. The impact of climate change, especially the gradual increase of average temperatures in the growing season, cannot be overlooked. It greatly affects, among other things, the sugar content of grapes. Calculations according to the Huglin Index and the Winkler Index were used to determine the relationship between climate and sugar content. These indexes summarize the course of temperatures during the entire vegetation period into a single numerical value. The results show that both indexes describe the effect of air temperature on sugar content in both wine regions of the Czech Republic in a statistically significant way. The Huglin Index shows a higher correlation rate. The Winkler Index proved to be less suitable for both areas. Alternatively, the Winkler Index calculated for a shorter growing season was tested, which showed a higher degree of correlation with sugar content, approaching the significance of the Huglin Index.

scholarly journals Phenotypic Characterization of Recent Clonal Lineages of Phytophthora infestans in the United States

Plant Disease ◽  
2013 ◽  
Vol 97 (7) ◽  
pp. 873-881 ◽  
Author(s):  
G. Danies ◽  
I. M. Small ◽  
K. Myers ◽  
R. Childers ◽  
W. E. Fry
Keyword(s):  
United States ◽  
Late Blight ◽  
Phytophthora Infestans ◽  
The United States ◽  
Phenotypic Characterization ◽  
Phenotypic Traits ◽  
Mating Types ◽  
Late Blight Disease ◽  
Blight Disease

Phytophthora infestans, the causal agent of late blight disease, has been reported in the United States and Canada since the mid-nineteenth century. Due to the lack of or very limited sexual reproduction, the populations of P. infestans in the United States are primarily reproducing asexually and, thus, show a simple genetic structure. The emergence of new clonal lineages of P. infestans (US-22, US-23, and US-24) responsible for the late blight epidemics in the northeastern region of the United States in the summers of 2009 and 2010 stimulated an investigation into phenotypic traits associated with these genotypes. Mating type, differences in sensitivity to mefenoxam, differences in pathogenicity on potato and tomato, and differences in rate of germination were studied for clonal lineages US-8, US-22, US-23, and US-24. Both A1 and A2 mating types were detected. Lineages US-22, US-23, and US-24 were generally sensitive to mefenoxam while US-8 was resistant. US-8 and US-24 were primarily pathogenic on potato while US-22 and US-23 were pathogenic on both potato and tomato. Indirect germination was favored at lower temperatures (5 and 10°C) whereas direct germination, though uncommon, was favored at higher temperatures (20 and 25°C). Sporangia of US-24 released zoospores more rapidly than did sporangia of US-22 and US-23. The association of characteristic phenotypic traits with genotype enables the prediction of phenotypic traits from rapid genotypic analyses for improved disease management.

scholarly journals Efficiency of phylloplane bacteria in controlling aerial tomato diseases under field conditions

2008 ◽  
Vol 34 (1) ◽  
pp. 86-87 ◽  
Author(s):  
Bernardo A. Halfeld-Vieira ◽  
Reginaldo S. Romeiro ◽  
Ann Mounteer ◽  
Eduardo S.G. Mizubuti
Keyword(s):  
Late Blight ◽  
Bacillus Cereus ◽  
Phytophthora Infestans ◽  
Field Conditions ◽  
Water Control ◽  
Tomato Plants ◽  
Tomato Diseases

The capacity of two bacteria isolated from the tomato phylloplane to control late blight (Phytophthora infestans) was investigated in the field, and compared against the effectiveness of spraying with the fungicide chlorothalonil (1.5 g a.i. L-1) or water (control). A 55% reduction in late blight intensity was observed in the leaves of the middle of the plant and 62% in those of the upper leaves when using the antagonist UFV-STB 6 (Novosphingobium capsulatum) as compared to the control. Isolate UFV-IEA 6 (Bacillus cereus) was able to reduce disease intensity by 55%, but only in the upper leaves of the tomato plants. Treatment with isolate UFV-STB 6 also led to a significant reduction in the percentage of fruits with late blight symptoms. The results demonstrate the potential of these two bacteria in controlling this disease.

scholarly journals Ovicidal effects of thiacloprid, acetamiprid, lambda-cyhalothrin and alpha-cypermethrin on Bruchus pisorum L. (Coleoptera: Chrysomelidae) eggs

2011 ◽  
Vol 47 (No. 3) ◽  
pp. 109-114 ◽  
Author(s):  
M. Seidenglanz ◽  
J. Rotrekl ◽  
J. Poslušná ◽  
P. Kolařík
Keyword(s):  
Czech Republic ◽  
Field Conditions ◽  
Egg Survival ◽  
The Czech Republic ◽  
Real Effects ◽  
First Instar ◽  
Lambda Cyhalothrin ◽  
Ovicidal Effects ◽  
Bruchus Pisorum

The effects of two pyrethroid (lambda-cyhalothrin, alpha-cypermethrin) and two neonicotinoid (acetamiprid, thiacloprid) insecticides on B. pisorum L. eggs were compared under field conditions in the Czech Republic in 2005&ndash;2007. The main objective of the study was to find out what real effects can be expected from the available insecticides registered in Europe when applied at the time of the first egg occurrence on lower pods. In general, the rates of Bruchus pisorum egg (+ first instar larvae) survival were significantly lower with all the insecticides compared in the study, in each of the three years (2005, 2006, 2007). The tested insecticides showed some ovicidal effects and also some larvicidal effects. The tested pyrethroids (lambda-cyhalothrin, alpha-cypermethrin) showed somewhat higher effectiveness in comparison with the neonicotinoids (acetamiprid, thiacloprid). Alpha-cypermethrin was the most effective in all three years. In 2006 and in 2007 this insecticide significantly reduced the rates of egg survival in comparison with acetamiprid. In contrast, acetamiprid was the least effective insecticide in each of the three years.

scholarly journals Gap regeneration and dynamics: the case study of mixed forests at Křtiny in the Czech Republic

2021 ◽  
Vol 67 (3) ◽  
pp. 135-147
Author(s):  
Maame Esi Hammond ◽  
Radek Pokorný ◽  
Lumír Dobrovolný
Keyword(s):  
Czech Republic ◽  
Natural Regeneration ◽  
Diversity Index ◽  
Growing Season ◽  
Growth Strategy ◽  
Small Scale ◽  
Mixed Forests ◽  
Tree Species Composition ◽  
The Czech Republic ◽  
Gap Regeneration

Abstract Gap regeneration remains the best silviculture technique for sustainable forest regeneration in mixed forests. The study examined tree species composition, diversity and dynamics of natural regeneration in gaps under three contrasting forest stands at Křtiny in the Czech Republic. In spring 2013, experimental gap design begins, when semi-permanent 1 m2 circular sub-sampling plots along North-South-East-West transects were delineated under 6 selected natural canopy openings ≤ 20 m2. In winter 2013/14, these naturally originated openings were artificially enlarged to the current gap sizes ranging between 255 and 1149 m2 through group felling. Natural regeneration in gaps was measured four times: from the growing season before disturbance (BD) in 2013 to the next three consecutive growing seasons after disturbance in 2014 – 2016, respectively. Seven (7) new species with light demanding growth strategy that were previously not present at mother stands were occurring there during the first growing season after disturbance (FGS), yielding the highest taxa (14 species) and diversity (Shannon diversity index, H = 1.7) while BD attained the lowest (8 species; H = 0.9), respectively. Study site being part of Fagus sylvatica vegetation community and providing favorable natural conditions for the optimal growth of Picea abies significantly explains the regeneration dominance of these species in gap regeneration from BD until the third growing season after disturbance (TGS), respectively. Small scale gap-disturbance contributed to the higher regeneration densities of all studied species during FGS. However, drought, competition from other life forms, and browsing activities substantially caused a progressive decline in natural regeneration during three consecutive years after disturbance.

scholarly journals Occurrence, development and economic importance of Phratora (= Phyllodecta) vitellinae (L.) (Coleoptera, Chrysomelidae)

2012 ◽  
Vol 52 (No. 8) ◽  
pp. 357-385 ◽  
Author(s):  
J. Urban
Keyword(s):  
Czech Republic ◽  
Growing Season ◽  
Economic Importance ◽  
The Czech Republic ◽  
Salix Fragilis ◽  
In Captivity

The paper summarizes results of the study of the occurrence, development and harmfulness of Phratora (= Phyllodecta) vitellinae (L.). The majority of studies was carried out in 1998 to 2005 in riparian and accompanying stands of the Svitava and Svratka rivers in the region of Brno and in a laboratory. Imagoes leave hibernation hiding places at the end of April and at the beginning of May. In captivity, they lived on Salix fragilis about 2.5 months damaging on average 28.6 cm<sup>2 </sup>leaf blades and laying on average 293 eggs. In the excessively warm growing season of 2005, imagoes lived about 3.5 months after hibernation, however, already after one month of feeding they fell in a month diapause at the beginning of June. Before its start, they damaged on average 12.8 cm<sup>2</sup> (after the diapause 14.4 cm<sup>2</sup>) leaves and laid on average 389 eggs (of this number, 260 eggs before and 129 after the diapause). Larvae damage about 4 cm<sup>2</sup> leaves during 2 to 3 weeks (in the laboratory during 12 to 13 days). After 2 to 3 weeks (in the laboratory after 10 to 12 days) from the cessation of feeding young beetles appear on trees. Imagoes of the 1<sup>st</sup> generation occur from mid-June to the beginning of October. During about 55 days of life, they damaged 19 cm<sup>2 </sup>leaves and laid on average 182 eggs. Imagoes of the 2<sup>nd</sup> generation occur from mid-August to the end of the growing season. After 10 to 14 days of feeding (without previous copulation), they take shelter in wintering places. In the laboratory, however, these imagoes damaged about 19 cm<sup>2</sup> leaves during 2 months and laid about 190 eggs. Wintering places were looked up by imagoes of the 3<sup>rd</sup> generation which damaged on average 4.2 cm<sup>2 </sup>leaves before hibernation. In the Czech Republic, P. vitellinae is usually bivoltine the 2<sup>nd</sup> generation being always incomplete.

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