Search
Search Results
-
Examination of the efficacy of different fungicides against Macrophomina phaseolina and Sclerotinia sclerotiorum in laboratory conditions
21-24Views:262Macrophomina phaseolina and Sclerotinia sclerotiorum are two significant fungal pathogens of sunflower. M. phaseolina causes charcoal rot and ashy stem blight in several important crop species. Sclerotinia sclerotiorum causes white mold disease which can occur as middle stalk rot, head rot and premature plant death. Due to the wide host range of the two pathogens and their survival structures, crop rotation cannot provide sufficient protection against them. In our experiment, we selected two fungicides, Mirage and Prosaro, which are widely used in practice, and we tested their efficacy against the two pathogens. The efficiency of these fungicides was tested at a concentration of 10; 20; 50; 100 and 500 ppm. The Prosaro totally inhibited the mycelial growth of both pathogens at a concentration of 50 ppm, 100 ppm and 500 ppm. The Mirage caused total mycelial growth inhibition in all treatments against both pathogens.
-
Host plant preference of Metcalfa pruinosa (Say, 1830) (Hemiptera: Flatidae) in the north of Hungary
84-95Views:251Citrus flatid planthopper, a native insect to North America had for a long time a scarce economic importance there. However, being polyphagous made little damage on citrus trees and some ornamentals. In 1979 it was introduced to Italy where it established and spread quickly. It is now an invasive alien species continually spreading in South and Central Europe causing considerable damage in fruit crops and various ornamentals. Present study shows the results of a series of observations carried out from 2011 to 2015 at a number of habitats in north of Hungary. The pest could be found at each habitat but the hedge, the tree row, the gardens and the orchard/vineyard were the most infested. Frequency and population density of Metcalfa pruinosa were considerable on Asteraceae, Cannabaceae, Fabaceae, Juglandaceae, Lamiaceae, Rosaceae and Sapindaceae. Typical vegetation could be functionally classified as ornamental plants, trees/shrubs, fruit plants, weeds and feral plants. Feral plants – some of them also invasive alien species – were found at each habitat. Plant species native to America were among them the most populated. As the hedgerows were neglected, and most gardens, orchards and vineyards abandoned, these are excellent conditions for the quick and long-lasting establishment of the pest as well as they may be reservoirs to infest cultivated fruit crops and ornamentals. The hedgerow was situated along a railway line. The length of similar hedges can be merely in Pest county several hundred km, which means M. pruinosa has plenty of opportunity for spreading along the railway and infest agricultural and ornamental cultures. On the surveyed alfalfa and maize fields, accidentally very few nymphs and adults were observed. Although, the population density of M. pruinosa was considerable on many hostplants, economic damage or yield losses could not be detected. Economic or significant damage was observed only on roses, raspberries and stinging nettle. This later is cultivated in Germany and Finland. The applied horticultural oil was efficient.
-
White rust species (Chromista, Peronosporomycetes, Albuginales, Albuginaceae) on common weeds in Hungary
30-33Views:247The obligate plant parasite fungi in the family Albuginaceae are responsible for causing white rust diseases on weeds and they are rather common worldwide. Weedy plants with characteristic symptoms have been collected in 2014 and 2015 on location Hajdú-Bihar and Jász-Nagykun-Szolnok counties in Hungary. The determination of the species were based on the morphological characters both pathogens and hosts. Albugo candida was determined on shepherd’s purse (Capsella bursa-pastoris). Common purslane (Portulaca oleracea) is a host for Wilsoniana portulacae. The fungus Wilsonia bliti (syn.: Albugo bliti), the causal agent of white rust disease was found on redroot pigweed (Amaranthus retroflexus).
-
Varietal dependent response of barley to soil-borne Waitea circinata infection
100-106Views:177The disease syndrome caused by Waitea circinata, a soil-borne pathogen introduced in the past decade into Carpathian basin, visually indistinguishable of those caused by various Rhizoctonia strains in diverse host plant. Dicotyledonaceous species in general proved to be more tolerant to this new pathogen than monotyledonaceous ones. This mesophilic fungus can seriously damage cereals. The barley varieties, similarly to other plants, exhibited highly different individual reaction to soil borne infection, Bivoy being the most while Maresi the less tolerant among the 9 tested varieties. Two groups could be separated on the base of their response to Rhizoctonia; Jubilant, Bivoy, Pasadena formed one group being moderately tolerant and Anabell, Scarlett, Rex and Omega the other group of more susceptibles. Three significant factors influence on the virulence of Rhizoctonia strains comprised 62% of total variation.
-
Inhibition of the spread of Sclerotinia sclerotiorum in aquaponics
5-8Views:290Sclerotinia sclerotiorum, which causes white mold, is a widespread pathogen. In 2020, a new host plant of this fungus, the watercress (Nasturtium officinale) was identified in Hungary in an aquaponic system. During the cultivation of watercress S. sclerotiorum was detected on the plant, the fungus caused a 30% yield loss. Fungicides should not be used against fungi in aquaponic systems. Non-chemical methods of integrated pest management should be used. These include biological control (resistant species, predators, pathogens, antagonist microorganisms), manipulation of physical barriers, traps, and the physical environment. In the aquaponic system, the removal of the growing medium (expanded clay aggregate pellets) solved the damage of Sclerotinia sclerotiorum 100%. By removing the expanded clay aggregate pellets, the environmental conditions became unfavorable for the development and further spread of the S. sclerotium fungus.
-
Seasonal changes of photosynthetical parameters as a results of forest gap model
133-136Views:176Photosynthetic parameters of English oak (Quercus robur L.) as a member of Querco robori-Carpinetum were investigated in two different habitat in terms of gap forest management: in the gap and in the host forest. The artifical opening process of the forest resulted in more light for growing saplings and need for acclimatization. Photosynthesis is one of the most important way for plant life and plant production. In the centre of photosynthetic efficiency the quality and quantity traits of photosynthetic pigments are standing. During our work some photosynthetic parameters of plants (in the gap and in the forest as well) were measured: relative chlorophyll content as SPAD index, chlorophyll a and b content, total chlorophyll content and ratio of chlorophyll a and b. Based on our results no significant differences among our data in early spring. Although, during the summer significant differences occurred between the measured values in the gap and in the forest area. Lower total chlorophyll content was experienced in the gap, than in the forest area due to the lower chlorophyll-b content. Because of the high light intensity higher chla/chlb ratio was measured in the gap. The lower chlorophyll contents of gap habitat may have a part of the acclimatization process of photosynthetic apparatus against high light stress, which can determinate the survival chance of individual.
-
Phytopatological properties of symbiotic Rhizoctonia solani strains associated to orchids
65-71Views:163The mycobiota of the Orchidarium of ELTE Botanical Garden (Budapest) has been studied applying aerobiological methods and isolating of tissue samples taken from 92 individuals of sixty orchid species. Among isolated basidiomycetaceous fungi 13 strains of Rhizoctonia solani were surviving in axenic culture. These symbiotic R. solani strains proved to be pathogenic on 24 cultivated plant species at varying degree. The symptoms of disease caused by R. solani strains isolated from orchids did not differ from that caused by reference strains. Three groups of strains could be separated regardless of their source or aggressivity. The host plants clustered into two groups, and their taxonomic position had no role in this respect. In general, we can assume that orchid associated Rhizoctonia strains are potential plant pathogens, and removed or withdrawn orchid stools should be treated as hazardous waste.
-
Susceptibility of stem infected sweet corn hybrids to common smut disease
55-57Views:428The common smut of maize (corn smut, Ustilago maydis /DC/ Corda) can cause large economic losses in susceptible sweet corn hybrids as well. The protection against this pathogen is fundamentally based on prevention. Many methods to control corn smut have been recommended or evaluated, including crop rotation, sanitation, seed treatments, modification of fertility, and biological control. In spite of these frequently mentioned control strategies, the host resistance seems to be the only effective method to manage common smut in those areas where Ustilago maydis is prevalent.
-
Examination of different fungicides against Macrophomina phaseolina in laboratory conditions
65-69Views:177In Hungary, sunflower is the third most important arable crop, which has a lot of pathogenic fungi. One of these fungi is the Macrophomina phaseolina, which is a well-known fungus in all over the world, since this pathogen has more than 700 host plants. In Hungary, several host plants can be found as well. The M. phaseolina produces microsclerotia, which can survive in the soil and residues for almost 10 years. For now, there is no efficient treatment against this pathogen because of this fungus, since it is extremely resistant and cannot be destroyed easily. The only effective treatment against the fungus is genetic defence. In this study, three different fungicides were tested in vitro against the fungus. The Mirage (prochloraz) seemed to be the most effective fungicide as it completely arrested the hyphal growth. In contrast, the Amistar Xtra (azoxystrobin and ciprochonazol) has only a minor effect on the growth of M. phaseolina. Thirdly, the Retengo (pyrachlostrobin) arrested the hyhpal growth of the fungus with 71% at 100 ppm, in other words, the use of this fungicide seems promising.
-
Ideas on the European stone fruit yellows – as an entomologist can see them
30-34Views:196The European stone fruit yellows (ESFY) is an important endemic disease in Europe which causes in both, the Mediterranean countries and Central Europe serious damage. Its pathogen is the ‘Candidatus Phytoplasma prunorum’. The treatment and healing of the diseased trees and plantations with chemicals do not promise success. Thus, prevention may be the only solution. The transmission and spread of the pathogen happen by infected propagation material (grafting) or a vector (the psyllid, Cacopsylla pruni). Mechanism of the pathogen’s transmission and population dynamics of the vector have been extensively investigated in several European countries, which may allow by the control of C. pruni even to hold back the disease. Diseased stone fruit trees and wild Prunus spp. as main host species play an important role in maintaining and spreading the pathogen. C. pruni collects the pathogen by feeding on these plants and it carries persistently ‘Ca. P prunorum’. Researchers in Hungary have been characterized the disease only in terms of plant pathology, but neither the significance of the vector nor the role of wild Prunus spp. have been studied. This summary intends to give clues to these researches, that not only axe and saw should be the instruments of national control, but knowing the role and population dynamics of the vector the stone fruit production should be more successful.
-
An unimportant insect pest with characteristic symptoms: Halticus apterus (Miridae)
19-23Views:206Halticus apterus, a tiny mirid bug with jumping hind legs has not been taught in agricultural entomology courses in Hungary. However, the most detailed agricultural entomology text book, the “Handbook of Agricultural Entomology” briefly presents the pest. Although, it is common in Hungary, its damage is insignificant because of the low density; it can cause quality loss in feed crops only. Nevertheless, its special symptom – spottedness – is worth taking into consideration. The author has been studying pests and natural enemies of alfalfa for a long time (at least ten years), so he focused attention on this species. Occurrence of H. apterus was only sporadic in the alfalfa field, but it showed characteristic and frequent symptoms at a density of averagely three individuals per alfalfa plants in mixed plant associations at the studied field edge. By presenting the damage appearance and form, it was possible to make a more accurate description of H. apterus’symptoms, and with evaluating relevant European references, also the detailed entomological characterisation, economic importance and assessment of future risks have been achieved. As a difference to former descriptions, the special leaf spottedness of H. apterus does not consist of homogenous round spots but rather of spherical conglomerations of tiny whitish dots caused by the piercing and sucking mouthparts and the injected saliva
-
Comparative Vertical Migration of Three Different Strains of Heterorhabditis bacteriophora and a Single Strain of Heterorhabditis megidis in Sand at 25°C
47-52Views:96Heterorhabditis bacteriophora and Heterorhabditis megidis) were tested for downward migration in 9.5 cm vertical sand columns at 25°C with and without a larva of the wax moth, Galleria mellonella, at the bottom. The number of infective juveniles (IJs) in the upper section decreased since the IJs gradually migrated down toward the Galleria larvae into the lower section of the shell vials. Only the isolate OH 25 behaved differently, because the number of IJs decreased this isolate in the lower section. This isolate was the quickest, since after 12 hrs, most IJs could be found in the lower section of the vials from this isolate. The number of IJs was so small in the lower section that 12 hrs after injection, only the isolates MHG 3 and OH 25 could kill the Galleria larvae.
Besides the fact that mortality occurred among the Galleria larvae with the above isolates, neither IJs nor adults could be detected in either living or dead Galleria larvae 12 hrs after IJ injection. It is noteworthy that the behavior of the isolate Megidis was different from the other isolates: the number of IJs was so negligible in the lower section of the vials that even after 36 hrs none of the Galleria died and, consequently, neither adults nor IJs could be detected after dissecting the Galleria larvae. Each isolate could reach the lower section of the vials, yet only the isolate Megidis could not infect and kill the host. After dissecting the larvae, most IJs and adults could be found in the isolate MHG 3 (95 IJs and adults altogether) 36 hrs after injection. -
Q-PCR analysis of the resistance of Hungarian Botrytis cinerea isolates toward azoxystrobin
41-44Views:120The genes being in the mitochondrial DNA primarily encode the enzymes of cellular respiration. Fungicides belonging to the family of quinol oxidase inhibitors (QoIs) play on important role in the protection against several plant diseases caused by fungi. These fungicides bind to the cytochrome bc1 complex so they block electron transport between cytochrome b and cytochrome c1. This way these fungicides inhibit the ATP synthesis consequently they inhibit the mitochondrial respiration. The QoI resistance has two mechanisms. One of them is the point mutation of the cytochrome b gene (CYTB), e.g. the substitution of a single glycine by alanine at position 143 results in high-resistance. The other is the cyanide-resistant alternative respiration sustained by the alternative oxidase.
In a cell there are several mitochondria. The phenomenon when the genomes of all mitochondria in the cell are identical is called homoplazmy. If in the cell there is wild and mutant mitochondrial DNA this is called heteroplasmy. Whether the mutation in the mitochondria causes fenotypical diversity or does not depend on the dose, i.e. it depends on the percentage of the changed mitochondrials. During our work we investigated Botrytis cinerea single spore isolates which have been collected in 2008-2009 on different host plants. Our goal was to decide whether heteroplasmy influences the level of resistance. We managed to detect the change of the level of heteroplasmy, so the change the level of the resistance due to the treatment with fungicide. -
Investigation of the mycelial compatibility of Macrophomina phaseolina in the Carpatian Basin
25-28Views:121Macrophomina phaseolina is a globally widespread fungal pathogen. The fungus has a very wide range of hosts. Under optimal conditions, M. phaseolina can cause serious damage tothe host plants. In this study, the mycelial compatibility of different M. phaseolina isolates was investigated. From 2019 to 2021, 12 sunflower samples were collected from different regions of the Carpathian Basin, 9 samples from Hungary, 1 sample from Austria, and 2 samples from Slovakia. The genetic variability of the pathogen is a critical problem in plant protection. Two compatible pathogen strains can easily exchange their genetic material for each other, which can lead to the development of resistance. All collected samples (12) were tested to examine their compatibility. Isolates from all tested samples were paired with isolates from all other samples thus, a total of 66 pairings were made. During the examinations of mycelial compatibility, only 20 pairs of all possible pairings were found to be incompatible, and all others (46) were found to be compatible.