- TEI of Thessaly, PLANT PRODUCTION, Faculty Memberadd
- PhD, University of Reading, School of Agriculture, Policy and Development. Subject : topic: Phytopathogenic fungi-Biological control.edit
Phoma stem canker is an internationally important disease of oilseed rape (Brassica napus), causing serious losses. This study describes the occurrence of phoma stem canker (caused by the species complex Leptosphaeria maculans and L.... more
Phoma stem canker is an internationally important disease of oilseed rape (Brassica napus), causing serious losses. This study describes the occurrence of phoma stem canker (caused by the species complex Leptosphaeria maculans and L. biglobosa), as well as the ...
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Foliar fungal diseases are a serious threat to winter wheat production and climate change appears to favor pathogens associated with leaf blotch and tan spot symptoms in the Mediterranean area. The present work aimed to highlight these... more
Foliar fungal diseases are a serious threat to winter wheat production and climate change appears to favor pathogens associated with leaf blotch and tan spot symptoms in the Mediterranean area. The present work aimed to highlight these risks and propose appropriate disease management strategies by evaluating the seed treatment with the Systiva® (BASF) fungicide as a means to protect the crop against foliar fungal infections during the early growing stages. Towards that aim, plant tissue symptoms affected by the pathogens Pyrenophora tritici-repentis and Septoria spp. were systematically recorded in a study field in the region of Larissa, central Greece for three years (2016–2018), and the findings were associated with the monthly weather anomalies. Consequently, for the growing period of 2021–2022, a field experiment was established in the same disease prone field, comparing different doses of the seed treatment with Systiva® fungicide against leaf blotch and tan spot diseases. The ...
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This paper discusses a process of developing the data analysis and modeling of Pasteuria penetrans spore attachment in vitro and in planta, based on the observation that the number of spores attaching to juveniles within a given time... more
This paper discusses a process of developing the data analysis and modeling of Pasteuria penetrans spore attachment in vitro and in planta, based on the observation that the number of spores attaching to juveniles within a given time increased by increasing the time of exposure to spores and the spores dose. Based on this, the P. penetrans spore attachment in vitro was modeled using the negative binomial distribution which permits decomposing the observation’s variability into three components: randomness, internal differences between individuals, and the presence of other external factors, e.g., the soil type. Additionally, we developed case-detection methods to explain P. penetrans spores’ attachment variability. The statistical methods developed in this paper show that a nematodes invasion is significant limited when second stage juveniles (J2s) are encumbered with seven P. penetrans spores. This research study concludes that the number of spores attached in J2s, the time of expo...
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This paper discusses a process of developing the data analysis and modeling of Pasteuria penetrans spore attachment in vitro and in planta, based on the observation that the number of spores attaching to juveniles within a given time... more
This paper discusses a process of developing the data analysis and modeling of Pasteuria penetrans spore attachment in vitro and in planta, based on the observation that the number of spores attaching to juveniles within a given time increased by increasing the time of exposure to spores and the spores dose. Based on this, the P. penetrans spore attachment in vitro was modeled using the negative binomial distribution which permits decomposing the observation’s variability into three components: randomness, internal differences between individuals, and the presence of other external factors, e.g., the soil type. Additionally, we developed case-detection methods to explain P. penetrans spores’ attachment variability. The statistical methods developed in this paper show that a nematodes invasion is significant limited when second stage juveniles (J2s) are encumbered with seven P. penetrans spores. This research study concludes that the number of spores attached in J2s, the time of expo...
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We examined the insecticidal effect of three different dust formulations, which were attapulgite (W), attapulgite mix with oregano essential oil with 52% carvacrol (D1), and attapulgite mix with oregano essential oil with 75% carvacrol... more
We examined the insecticidal effect of three different dust formulations, which were attapulgite (W), attapulgite mix with oregano essential oil with 52% carvacrol (D1), and attapulgite mix with oregano essential oil with 75% carvacrol (D2), in four major stored-product beetle species, Sitophilus oryzae (L.), Tribolium confusum Jacquelin du Val, Rhyzopertha dominica (F.), and Trogoderma granarium Everts. Sitophilus oryzae was the most susceptible at all three formulations, followed by T. confusum and R. dominica. In contrast, T. granarium larvae showed the lowest mortality rates even on the 14th day of observation and at the highest concentration (2000 ppm). Progeny production was particularly reduced for all species relative to the controls. Nevertheless, complete suppression of the offspring was observed only in the case of T. confusum and S. oryzae, while R. dominica was less susceptible to all three dust formulations, giving an average of up to 20 individuals per vial at 2000 pp...
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We examined the insecticidal effect of three different dust formulations, which were attapulgite (W), attapulgite mix with oregano essential oil with 52% carvacrol (D1), and attapulgite mix with oregano essential oil with 75% carvacrol... more
We examined the insecticidal effect of three different dust formulations, which were attapulgite (W), attapulgite mix with oregano essential oil with 52% carvacrol (D1), and attapulgite mix with oregano essential oil with 75% carvacrol (D2), in four major stored-product beetle species, Sitophilus oryzae (L.), Tribolium confusum Jacquelin du Val, Rhyzopertha dominica (F.), and Trogoderma granarium Everts. Sitophilus oryzae was the most susceptible at all three formulations, followed by T. confusum and R. dominica. In contrast, T. granarium larvae showed the lowest mortality rates even on the 14th day of observation and at the highest concentration (2000 ppm). Progeny production was particularly reduced for all species relative to the controls. Nevertheless, complete suppression of the offspring was observed only in the case of T. confusum and S. oryzae, while R. dominica was less susceptible to all three dust formulations, giving an average of up to 20 individuals per vial at 2000 pp...
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In this article we present with STATA regression models suitable for analyzing over-dispersed count outcomes. Specifically, the Negative Binomial regression can be an appropriate choice for modeling count variables, usually for... more
In this article we present with STATA regression models suitable for analyzing over-dispersed count outcomes. Specifically, the Negative Binomial regression can be an appropriate choice for modeling count variables, usually for over-dispersed count outcome variables. The common problem with count data with zeroes is that the empirical data often show more zeroes than would be expected under either Poisson or the Negative Binomial model. We concluded, this publications showcases that Zero-inflated models can be used to model count data that has excessive zero counts.
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In this article we present with STATA regression models suitable for analyzing over-dispersed count outcomes. Specifically, the Negative Binomial regression can be an appropriate choice for modeling count variables, usually for... more
In this article we present with STATA regression models suitable for analyzing over-dispersed count outcomes. Specifically, the Negative Binomial regression can be an appropriate choice for modeling count variables, usually for over-dispersed count outcome variables. The common problem with count data with zeroes is that the empirical data often show more zeroes than would be expected under either Poisson or the Negative Binomial model. We concluded, this publications showcases that Zero-inflated models can be used to model count data that has excessive zero counts.
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Pasteuria penetrans is a biological control agent of root-knot nematodes ( Meloidogyne spp.), preventing root invasion by second-stage juveniles (J2s), and eventually causing females sterility and death. greatest control effects for P.... more
Pasteuria penetrans is a biological control agent of root-knot nematodes ( Meloidogyne spp.), preventing root invasion by second-stage juveniles (J2s), and eventually causing females sterility and death. greatest control effects for P. penetrans depend on the numbers of endospores attached to nematode cuticles. a method based on digital image analysis was used to record the effects of endospore attachment on the movements of juvenile root-knot nematodes, using a model based on the centroid point. Data showed that the numbers of endospores attached to the cuticle influenced nematode movement. At high endospore attachment levels (20‒30 per J2), nematodes did not show directional movement, whereas nematodes encumbered with five to eight spores showed limited directional movement, compared to those without endospores. nematode cephalic region turns were modelled using a markov chain, showing that P. penetrans endospores affected movements. Less nematodes invaded and established on tomat...
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Pasteuria penetrans is a biological control agent of root-knot nematodes ( Meloidogyne spp.), preventing root invasion by second-stage juveniles (J2s), and eventually causing females sterility and death. greatest control effects for P.... more
Pasteuria penetrans is a biological control agent of root-knot nematodes ( Meloidogyne spp.), preventing root invasion by second-stage juveniles (J2s), and eventually causing females sterility and death. greatest control effects for P. penetrans depend on the numbers of endospores attached to nematode cuticles. a method based on digital image analysis was used to record the effects of endospore attachment on the movements of juvenile root-knot nematodes, using a model based on the centroid point. Data showed that the numbers of endospores attached to the cuticle influenced nematode movement. At high endospore attachment levels (20‒30 per J2), nematodes did not show directional movement, whereas nematodes encumbered with five to eight spores showed limited directional movement, compared to those without endospores. nematode cephalic region turns were modelled using a markov chain, showing that P. penetrans endospores affected movements. Less nematodes invaded and established on tomat...
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A total of 27 walnut (Juglans regia) cultivars (14 lateral and 13 terminal fruit fullness cultivars), 12 selections and 12 crosses were evaluated for their resistance to the walnut blight bacterium Xanthomonas arboricola pv. juglandis.... more
A total of 27 walnut (Juglans regia) cultivars (14 lateral and 13 terminal fruit fullness cultivars), 12 selections and 12 crosses were evaluated for their resistance to the walnut blight bacterium Xanthomonas arboricola pv. juglandis. Healthy nuts were inoculated with pure bacterial cultures isolated from diseased nuts. Two weeks after inoculation, the frequency of successful infections, as well as the disease severity was recorded and the index of varietal susceptibility (IVS) was calculated for each treatment. Based on these results walnut cultivars, selections and crosses were ranked in five classes of susceptibility (A to E). The experiment was repeated for two consecutive years, 2007 and 2008. Results showed that all the artificially infected nuts showed typical bacterial blight symptoms as compared to the negative control. Among the cultivars tested Amigo, Asley, Eliana, Franquette and Spurgcan were the less susceptible with average IVS ranging from 13.1 to 24.4, therefore ra...
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A total of 27 walnut (Juglans regia) cultivars (14 lateral and 13 terminal fruit fullness cultivars), 12 selections and 12 crosses were evaluated for their resistance to the walnut blight bacterium Xanthomonas arboricola pv. juglandis.... more
A total of 27 walnut (Juglans regia) cultivars (14 lateral and 13 terminal fruit fullness cultivars), 12 selections and 12 crosses were evaluated for their resistance to the walnut blight bacterium Xanthomonas arboricola pv. juglandis. Healthy nuts were inoculated with pure bacterial cultures isolated from diseased nuts. Two weeks after inoculation, the frequency of successful infections, as well as the disease severity was recorded and the index of varietal susceptibility (IVS) was calculated for each treatment. Based on these results walnut cultivars, selections and crosses were ranked in five classes of susceptibility (A to E). The experiment was repeated for two consecutive years, 2007 and 2008. Results showed that all the artificially infected nuts showed typical bacterial blight symptoms as compared to the negative control. Among the cultivars tested Amigo, Asley, Eliana, Franquette and Spurgcan were the less susceptible with average IVS ranging from 13.1 to 24.4, therefore ra...
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The paper describes the morphology of two species of powdery mildew of Cydonia oblonga caused by Podosphaera clandestina and Setoerysiphe kashmeriensis reported for the first time in cydonia orchards in Greece.
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Pseudomonas oryzihabitans (=Flavimonas oryzihabitans), a symbiont of the entomopathogenic nematode Steinernema abbasi significantly inhibited the mycelium growth of Fusarium oxysporum and Rhizoctonia solani in vitro. Antifungal compounds... more
Pseudomonas oryzihabitans (=Flavimonas oryzihabitans), a symbiont of the entomopathogenic nematode Steinernema abbasi significantly inhibited the mycelium growth of Fusarium oxysporum and Rhizoctonia solani in vitro. Antifungal compounds diffused from P. oryzihabitans exhibited chemotaxis toward Fusarium and Rhizoctonia mycelia in soft (0.2%) agar. Activity occurred at 15 - 28 degreesC but was strongest at the higher temperature. P. oryzihabitans cells were also tested for their root colonization and biocontrol abilities. A polyclonal antibody confirmed the bacterium had colonized roots. P. oryzihabitans induced soil suppressiveness against Fusarium oxysporum
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ABSTRACT An experiment was carried out where gin trash that is a weakly alkaline material and a commercial organic fertiliser was added to an acid soil. Also, the residues of cottonseed acid delimiting product, were added to a calcareous... more
ABSTRACT An experiment was carried out where gin trash that is a weakly alkaline material and a commercial organic fertiliser was added to an acid soil. Also, the residues of cottonseed acid delimiting product, were added to a calcareous soil. After nine weeks of incubation the effect of the above mentioned added materials on soil nitrification was evaluated. Another experiment was carried out to investigate the possibility of gin trash, cottonseed acid delimiting product, a commercial organic fertiliser and a sample of dried manure in disseminating important cotton pathogens (Fusarium oxysporum, Verticillium dahliae, Rhizoctonia solani, Pythium ultimum and Thielaviopsis basicola); also to test their effect on the growth of the above mentioned pathogens. The cottonseed gin trash acted effectively to nitrification process only at the rate 3% in organic matter, whereas cottonseed acid delimiting product demonstrated a negative effect on nitrification at the rates 2% and 3% in organic matter. All tested materials (cotton-seed acid delimiting product, gin trash, organic fertilizer and manure) when added to selective culture media, did not find to carry any inoculum of the above mentioned cotton pathogens but favoured saprophytic organisms growth. On the other hand, only the cottonseed acid delimiting product obscured the growth of all tested cotton pathogens, whereas gin trash promoted growth of P. ultimum and R. solani, when these two materials were used as soil amendments.
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Research Interests: Geography and Gelechiidae
Root-Knot Nematodes (RKN) Meloidogyne spp. significantly affects glasshouse tomatoes in Central Greece. Elimination or halting J2s could be an efficient strategy to control RKN. Recently, it was reported that a commercial product of Neem... more
Root-Knot Nematodes (RKN) Meloidogyne spp. significantly affects glasshouse tomatoes in Central Greece. Elimination or halting J2s could be an efficient strategy to control RKN. Recently, it was reported that a commercial product of Neem (Azadirachta indica) seed extract (Azadirachtin 1% Emulsion Concentrate-EC) significantly reduced the number of galls on tomato roots and egg masses, compared to the untreated control. In the present study neem proved to have a direct immobilising effect on RKN J2s. Different concentrations (0, 0.05, 0.1, 0.25, 0.5, 1, 5, 10, 25 and 50%) of the tested neem product were applied with water containing fresh J2s and in soil naturally infected with RKN. Records of immobilised J2s were taken after 10 min, 1 h, 6 h, 24 h and 72 h of Neem application in water and after six days of neem application into the soil. Neem solution concentrations 5% and 10%, resulted in 85% ± 3.2 and 100% of immobilised J2s. The same concentrations of neem when were added in the water for nematode extraction from the soil, resulted 14.25% ± 4.01 and 1.7%, of J2s extracted from the soil with a significant concentration effect (P = 0.008), compared to the untreated control. However, the neem product at high application dose significant damage the tomato plants caused phytoxicity.
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Background The profitable use of the large amounts of olive oil mill wastes produced in Greece, as source of soil organic matter, might be probably beneficial to soil microorganism activity. Results A high rate of organic matter... more
Background The profitable use of the large amounts of olive oil mill wastes produced in Greece, as source of soil organic matter, might be probably beneficial to soil microorganism activity. Results A high rate of organic matter biodegradation was observed in soil samples amended with the liquid form of olive mill wastewater, whereas the vice versa results were obtained with the solid form. When the soil was amended with a mixture of both olive mill waste forms, liquid (L) and solid (S), the organic matter of the solid waste (S) showed a well-improved biodegradation; the available forms of P, K, Zn, Mn, and Cu were increased, especially in treatments where the olive mill wastewater, liquid form, was threefold in comparison to the solid form. Moreover, the soil amended with the solid (S) form of olive mill waste reduced bacterial growth significantly, and both waste forms act negative impacts to soil-borne fungi belonging to the genus Rhizopus. Conclusions The results of this work de...
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ABSTRACT Pasteuria penetrans is a naturally occurring bacterial parasite of plant parasitic nematodes showing satisfactory results in a biocontrol strategy of root-knot nematodes (Meloidogyne spp.). The endospores attach to the outside... more
ABSTRACT Pasteuria penetrans is a naturally occurring bacterial parasite of plant parasitic nematodes showing satisfactory results in a biocontrol strategy of root-knot nematodes (Meloidogyne spp.). The endospores attach to the outside nematode body wall (cuticle) of the infective stage second-stage juveniles (J2) of Meloidogyne populations. Optimal attachment level should be around 5-10 endospores per juvenile, as enough endospores will initiate infection without reducing the ability of the nematode to invade roots. Greater than 15 endospores may disable the nematode in its movements, and invasion may not take place. In this research, evidence is provided that P. penetrans spores disturbed the nematode forward movement by disorganising the nematode's head turns. The results based on Markov chain and Cochran probability model show that even a low number of 5-8 spores of P. penetrans attached to the nematode cuticle have a significant impact on that movement, which plays a role in nematode locomotion.
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Pasteuria penetrans controls root knots nematodes (Meloidogyne spp.) either by preventing invasion or by causing female sterility. The greatest control effect of P. penetrans occurred when an efficient quantity of P. penetrans spores... more
Pasteuria penetrans controls root knots nematodes (Meloidogyne spp.) either by preventing invasion or by causing female sterility. The greatest control effect of P. penetrans occurred when an efficient quantity of P. penetrans spores attached to nematodes cuticle. The number of spores attaching to J2s within a given time increased with increasing the time of attachment. Based to that, we produced attachment data in vitro recorded encumbered nematodes 1, 3, 6 and 9 h after placing nematodes in a standard P. penetrans spore suspensions. From the count data obtained we modeled P. penetrans attachment using the Poisson and the negative binomial distribution. Attachment count data observed to be over dispersed with respect to high numbers of spores sticks on each J2 after at 6 and 9 h after spores application. We concluded that negative binomial distribution was shown to be the most appropriate model to fit the observed data sets considering that P. penetrans spores are clumped.
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Armillaria mellea and Rosellinia necatrix were observed as the most aggressive rot pathogens of Ficus carica cultivar (Smyrna) in central Greece. Both pathogens cause fig rot root, stress old trees and kill young plants. Common symptoms... more
Armillaria mellea and Rosellinia necatrix were observed as the most aggressive rot pathogens of Ficus carica cultivar (Smyrna) in central Greece. Both pathogens cause fig rot root, stress old trees and kill young plants. Common symptoms shown by infected trees are, yellowing of the leaves, early leaf fall, premature autumn color, splitting of the bark, plant defoliation and plant death. Both diseases are confirmed by the presence of white mycelium found under the bark and on the infected roots. Infections are common in fig cultivars near the forest. INTRODUCTION Armillaria mellea and Rosellinia spp. is recorded all over the world as a root rot pathogen of forest and orchard trees, and is common in both temperate and tropical regions. A. mellea is a vigorous pathogen of many important trees (Arora 1986). The fungus lives as parasites on living host tissue or as saprophytes on dead plant material. A. mellea invades healthy trees via the roots and develops a white mat mycelium under th...
Mouldiness is one of the most common microbiological defects, found in bakery industry. It is estimated that approximately 1-5% of the bread production goes wrong due to fungi activity. Referring to bread, mold contamination determines... more
Mouldiness is one of the most common microbiological defects, found in bakery industry. It is estimated that approximately 1-5% of the bread production goes wrong due to fungi activity. Referring to bread, mold contamination determines not only changes in color, taste, but also loss of the food quality as a result of possible formation of mycotoxins. Mouldiness is caused by external contamination of bread after baking, because the existing spores in flour during a normal technological process don’t have any multiplication conditions, and during baking they are destroyed. Bread contamination with molds, may occur in the following steps: the transportation of bread; during cooling and storage; while cutting and packing (optional operation). Propagation of mold spores and contamination of bread can take place indirectly by air in the storage room (the air) or by direct contact with boxes, crates, hauling equipment etc. Among the molds that frequently contaminate bread during storage, t...
In this study was investigated the effect of manure and cocoa shell biomass addition on soil chemical properties and microflora, when the above mentioned organic materials areused in different proportions in soil mixtures. For this... more
In this study was investigated the effect of manure
and cocoa shell biomass addition on soil chemical
properties and microflora, when the above mentioned
organic materials areused in different proportions in
soil mixtures. For this reason different amounts (0.2,
0.4, and 0.6g) of air dried cocoa beans residue, were
mixed with 50g of soil and 5.0g of manure. The
control mixtures that contained only soil and manure
as well as the mixtures which contained different
amount of cocoa shells, were placed in incubator at
28oC for a period of 21 weeks. The organic matter
and the concentration of nutrient elements in the soil,
manure, cocoa shells biomass and in their mixtures,
were measured before and after the incubation
period. The results showed that the addition of more
than 1% of cocoa shell biomass to soil-manure
mixtures, may influence the mineralization of N, C
and K, and reduce the time needed for mixtures
maturation. The higher organic P content measured
in mixtures contained lower than 1% cocoa shell
biomasswhere the microbial activity was still high.
However the concentration of the available P was not
affected from the addition of cocoa shell biomass to
the soil-manure mixtures.
and cocoa shell biomass addition on soil chemical
properties and microflora, when the above mentioned
organic materials areused in different proportions in
soil mixtures. For this reason different amounts (0.2,
0.4, and 0.6g) of air dried cocoa beans residue, were
mixed with 50g of soil and 5.0g of manure. The
control mixtures that contained only soil and manure
as well as the mixtures which contained different
amount of cocoa shells, were placed in incubator at
28oC for a period of 21 weeks. The organic matter
and the concentration of nutrient elements in the soil,
manure, cocoa shells biomass and in their mixtures,
were measured before and after the incubation
period. The results showed that the addition of more
than 1% of cocoa shell biomass to soil-manure
mixtures, may influence the mineralization of N, C
and K, and reduce the time needed for mixtures
maturation. The higher organic P content measured
in mixtures contained lower than 1% cocoa shell
biomasswhere the microbial activity was still high.
However the concentration of the available P was not
affected from the addition of cocoa shell biomass to
the soil-manure mixtures.
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Pseudomonas oryzihabitans, a bacterium associated with the entomopathogenic nematode Steinernema abbasi acted as a biopesticide against the soil-borne pathogens Fusarium oxysporum and root-knot nematodes (Meloidogyne spp.), when applied... more
Pseudomonas oryzihabitans, a bacterium associated with the entomopathogenic nematode Steinernema abbasi acted as a biopesticide against the soil-borne pathogens Fusarium oxysporum and root-knot nematodes (Meloidogyne spp.), when applied in the absence of the nematode vector. We investigated the role of bacterial and bacteria cell- free culture filtrates in biocontrol in vitro assays and the synthesis of secondary metabolites. Bacteria cell- free culture filtrates showed antifungal and nematicidal activity against F. oxysporum and Meloidogyne spp. respectively in vitro. Bacterial cells produce diffusible secondary metabolites in vitro and suppress fungus (F. oxysporum) disease in planta. An amount of phenazine-1carboxylic acid (PCA) synthesized from P. oryzihabitans was detected in vitro. Moreover the inhibition of the fungal growth in cultures and beneficial effects on tomato plants infected with the fungus and nematodes is demonstrated.