Uticaj abiotskih činilaca na pojavu i razvoj biljnih bolesti

Factors of the environment where a host plant develops and grows permanently effect the beginning, development, course and, what is even more important in agricultural practice, intensity and harmfulness of a particular disease. The effects of environmental factors are of equal importance for both plant fungal and bacterial diseases but of less importance for diseases caused by phytopathogenic viruses. Although the effects are permanent, they vary in intensity due to changing environmental factors. Effects of abiotic factors, primarily of temperature and moisture, on plant diseases' intensity and development are crucial because, in most cases, if these factors are unfavorable, the disease does not develop at all despite the presence of a host plant and a pathogen. Abiotic factors affect concurrently a host plant and a causal agent. The effect on a causal agent is very important, because most pathogenic fungi do not live on a plant to the very moment of infection, therefore environmental factors have immediate effects on their development and survival. There is no universal rule about the effects of environmental factors on the occurrence and development of plant diseases, since each individual organism undergoes these effects differently.Faktori spoljne sredine u kojoj se biljka domaćin razvija i raste stalno utiču na početak, razvoj i tok i stoje za praksu od neobičnog značaja, intenzitet, a time i štetnost određene bolesti. Taj uticaj je podjednak za mikoze i bakterioze, a od manjeg značaja je kod bolesti izazvanih fitopatogenim virusima. On je neprestan, ali je, s obzirom da se faktori spoljne sredine menjaju, različitog intenziteta. Uticaj abiotskih činilaca, a pre svega temperature i vlage, na razvoj i intenzitet biljnih bolesti je veoma bitan, tako da se u najvećem broju slučajeva, ako su oni nepovoljni, bolest uopšte ne razvija, iako su prisutni i biljka domaćin i sam patogeni organizam. Abiotski činioci ne utiču samo na biljku domaćina, nego istovremeno i na uzročnika bolesti. Taj uticaj na uzročnika bolesti je vrlo bitan, pošto se većina patogenih gljiva nalazi, sve do trenutka infekcije izvan biljke, tako da faktori spoljne sredine direktno utiču na njihov razvoj i održanje. Pošto je taj uticaj na svaki pojedini organizam različit, ne postoji opšte pravilo o uticaju faktora spoljne sredine na pojavu i razvoj biljnih bolesti.

Otpornost biljaka prema biljnim bolestima

Plants are continuously exposed to the attack of several thousand of different strains of fungi, bacteria, viruses and other microorganisms. A plant can be attacked by thousands, hundreds and in the case of leaf spot in woody plants, even by hundreds of thousands of a single pathogen individuals. However, despite being infected, many plants manage to survive and produce relatively high yields (Agrios, 1997). This means that they are not only a passive subject of continuous microbial attack but also interact with them, which involves a broad spectrum of defense mechanisms (Jackson and Taylor, 1996; Osborne, 1996). To prevent attack of a pathogen, plants defend themselves by a combination of structure elements, which is a physical barrier to entry and spread of a pathogen (passive defense), and of biochemical reactions taking place in plant cells and tissues after the attack, when the compounds produced become either toxic to a pathogen or the conditions created inhibit its development in a plant (actively induced defense) (Agrios, 1997). A disease develops after a pathogen escapes plant passive defense and timely activation of induced defense in an attacked tissue, or overcomes induced defense by the secretion of toxins and enzymes (Alfano and Collmer, 1996; Jackson and Taylor, 1996). The characteristics of both host plant and parasite are determined by their genetic structure i.e. their DNA that is functionally organized through numerous genes. Many plants possess larger or smaller resistance whereby they tend to prevent or slow down the entry and spread of a disease causal agent. The degree of resistance or susceptibility of a host plant varies and the pathogen exhibits different degrees of virulence too. Therefore, the outcome of any disease attack is different. .Biljke su izložene konstantnom napadu nekoliko hiljada različitih vrsta gljiva, bakterija, virusa i dragih mikroorganizama. Jednu biljku mogu da napadnu stotine, hiljade, a u slučaju lisne pegavosti drvenastih biljaka i stotine hiljada individua jednog patogena. Međutim, i pored ostvarene infekcije, mnoge parazitirane biljke uspevaju da prežive i ostvare prihvatljiv prinos (Agrios, 1997). To znači da one nisu samo pasivni predmet stalnog napada mikroorganizama, nego su sa njima u interakciji koja obuhvata i spektar odbrambenih mehanizama (Jackson and Taylor, 1996; Osborne, 1996). Od napada patogena biljke se brane kombinacijom strukturnih elemenata, koji predstavljaju fizičku barijeru za prodor i širenje patogena (pasivna odbrana) i biohemijskih reakcija koje se odigravaju u biljnim ćelijama i tkivima posle napada, pri čemu nastaju jedinjenja koja su ili toksična za patogena, ili stvaraju uslove koje inhibiraju njegov razvoj u biljci (aktivna indukovana odbrana) (Agrios, 1997). Do bolesti dolazi kada patogen zaobiđe pasivnu odbranu biljke i blagovremeno izbegne aktiviranje indukovane odbrane u napadnutom tkivu ili lučenjem toksina i enzima savlada indukovanu odbranu (Alfano and Collmer, 1996; Jackson and Taylor, 1996). Svojstva i biljke - domaćina i parazita su određene njhovim genetičkim materijalom, tj. njihovim DNA koja je funkcionalno organizovana kroz brojne gene. Mnoge biljke imaju veću ili manju otpornost kojom nastoje da zaustave ili uspore prodor i širenje prouzrokovača bolesti. Stepen otpornosti ili osetljivosti biljke domaćina je različit, a i patogen pokazuje različit stepen virulentnosti. Zbog toga je ishod svakog oboljenja različit

Uzročnici sušenja i propadanja trešnje

In all areas of our country it was seen the appearance of decay of cherry tree plantations because of premature dying of trees. Disease is of complex nature, and as causers in literature are quoted different parasites, of which the most attention is payed to fungus Monilinia laxa and verticilium albo-atrum and to bacteria Pseudomonas syringea pv. syringea and Pseudomonas syringea pv. morsptunorum. Although it is about different parasites symptoms which are appeared on cherry are very similar (dying of flowers, leaves, tree and branches cancer and at the end fruit tree dying). In the aim of undertaken the concrete measures of cherry tree dying causers it is necessary to know the etymology of disease. Knowledge of the cycle of parasite development enable to reveal this stages in the development when it is the most susceptible to application of certain measures of protection. Because of this reason in this work are in detail described changes to which bring this mentioned parasites, as well as their cycle of development, timely intervention by the most effective means would contribute to the control of dying causers, and by itself to the increase of cherry production, as well as very esteemed and wanted fruit on a our market. .U svim područjima naše zemlje zapažena je pojava propadanja zasada trešanja usled prevremenog sušenja stabala. Oboljenje je kompleksne prirode, a kao prouzrokovači u literaturi se navode razni paraziti, od kojih se najviše pažnje poklanja gljivama Monilinia laxa i Verticilium albo-atrum i bakterijama Pseudomonas syringae pv. syringae i Pseudomonas syringae pv. morsprunorum. Iako se radi o različitim parazitima simptomi koji se javljaju na trešnji su veoma slični (sušenje cvetova, listova, rak-rane na stablu i granama i na kraju sušenje voćke). U cilju preduzimanja konkretnih mera suzbijanja uzročnika sušenja trešnje neophodno je poznavati etiologiju bolesti. Poznavanje ciklusa razvića parazita omogućava da otkrijemo one faze u razvoju kada je najosetljiviji na primenu određenih mera zaštite. Iz tog razloga u ovom radu su detaljno opisane promene do kojih dovode pomenuti paraziti, kao i njihov ciklus razvića. Pravovremena intervencija najefikasnijim sredstvima doprinela bi suzbijanju uzročnika sušenja, a samim tim povećanju proizvodnje trešanja, kao veoma cenjenog i traženog voća na našem tržištu.

Fire blight of pear in Yugoslavia

Fire blight of pear, caused by Erwinia amylovora (Burr.) Winslow, et al., is one of the oldest and the most destructive disease caused by bacteria on pome fruits. This disease is most dangerous on pear (Pyrus sp.), making commercial pear growing under certain conditions impossible. First record of this vicious pear disease in our country was in 1990 in several localities: Šabac and Djakovica on pear, Leskovac, Bojnik, Kosančič, Lebane and Vučje on pear and quince and Vranje and Vladičin Han on pear, quince and hawthorn. Apple trees were infected sporadically and these infections were less significant. Among pear cvs. present in Yugoslavia susceptible ones are William's, St. Maria, Passe Crassane, Abbe Fetel, Kocijeva, Kaludjerka, Packham's Triumph and others. In the spring, the first symptom usually occurs on flowers that become dark brown in color and remain hanging on branches. Disease spreads very fast on leaves and branches. Young trees in the nursery and in the orchard may be killed to ground by single infection in one season. Since bacterial fire blight is of recent occurrence in our country, control measure mainly consists of permanent supervision, isolation of areas with disease, restricted distribution of scions and rootstocks, eradication of diseased tress (by cutting and burning) and other similar practices

Framing resilience in relation to territorialisation

This article has no abstract.nonPeerReviewe

Proizvodnja certificiranog sadnog materijala voćaka i vinove loze

Although an initial step, the production of reproductive material and nursery stock of fruit crops and grapevines ranks first in terms of successful and profitable production. Nursery stock which is not true-to-type and infected with viruses, viroids and phytoplasms may endanger the following steps within production, minimazing huge financial investments in the planting establishment and its maintenance. Over a long-term in most developed countries, the programmes and schemes related to production of the certified reproductive material and nursery stock have been under way. The production of quality virus-free or viruses tested reproductive material and nursery stock has been in accord with strictly defined stages and work procedures for each classified category. The paper deals with the categorization of reproductive material and nursery stock, as well as with the procedures for obtaining of the specific categories and scheme for fruit crops and grapevines certification. The particular sress was laid on the major viruses and other infective pathogenes on fruit crops and grapevines, their detection methods, coupled with the necessity for the haromonization of the existing regulation in our country with the law regulation of the European Union with the aim to obtain quality nursery stock and create the possibility to take a share within the unique market of the region and Europe.Proizvodnja reprodukcionog i sadnog materijala voćaka i vinove loze, mada početni, predstavlja jedan od najvažnijih koraka u uspešnoj i rentabilnoj proizvodnji. Sortno neispravan i virusima, viroidima ili fitoplazmama zaražen sadni materijal maze ugroziti naredne korake proizvodnje i učiniti bezvrednim velika materijalna ulaganja u podizanje i održavanje zasada. U većini razvijenih zemalja već duži niz godina funkcionišu programi i seme proizvodnje certificiranog reprodukcionog i sadnog materijala. Proizvodnja kvalitetnog bezvirusnog ill na viruse testiranog reprodukcionog i sadnog materijala se obavlja po strogo definisanim fazama i procedurama rada za svaku propisanu kategoriju. U ovom radu data je kategorizacija reprodukcionog i sadnog materijala, kao i načini dobijanja pojedinih kategorija i šema certificiranja voćaka i vinove loze. Istaknuti su najvažniji virusi na voćkama i vinovoj lozi, načini detekcije ovih virusa, kao i neophodnost harmonizacije postojeće zakonske regulative u našoj zemlji sa zakonskom regulativom Evropske Unije, u cilju obezbeđivanja neophodnog kvaliteta sadnog materijala i otvaranja mogućnosti za uključenje u jedinstveno tržište regiona i Evrope

Effect of virus diseases on some major production characteristics of bean cv. Improved Gradištanac

The objective of the study has been to analyze the behavior of some bean (cv. Improved Gradištanac) lines to virus diseases under field conditions. The following five lines of the cultivar were studies: 12, 19, 29, 38 and 45. The presence of both bean common mosaic virus and cucumber mosaic virus was previously confirmed on mother plants. Mechanical inoculation of indicator plants was previously employed in order to test the symptoms of virus diseases. Been seeds were sown in bulks of 80 × 80 cm spaced rows. There were 45 bulks for each of the lines studies. Virus-free seeds of the lines analyzed were used as control. Apart from some phonologically phases (emergence, flowering and ripening stages) the following traits were assessed: total plant height, plant height at first pod, pod number per plant, seed number per pod as well as total yield per unit of area. Based on the results of a 2-year trial it can be concluded that virus diseased bean plants were less vigorous compared with virus-free control plants. All the traits analyzed including yield per unit of area were unfavorably effected. On average virus diseases plants exhibited stunting by approx. 13%, smaller number of seed per plant (approx.13%) and a 25-40% lower yield per hectare

Role of bean seed in transmitting bean common mosaic virus and cucumber mosaic virus

Bean plants have been reported to be the host plants for a number of viruses. Among them the most common are bean common mosaic virus, bean yellow mosaic virus and cucumber mosaic virus. Bean common mosaic virus and cucumber mosaic virus are known to be transmitted by seeds of some plants. The objective of the study was to analyze the role of bean seed in transmitting the above mentioned viruses. The following two bean cultivars were involved in the study: cv. Improved Gradištanac and its lines and cv. Tetovac. Plants which have previously been tested and confirmed as virus diseased were grown under field conditions. Seeds were harvested and sown in pots with sterile soil. Emergence, growth and the incidence of virus symptoms were assessed under greenhouse conditions. The incidence of virus diseases on seedlings were tested with the help of mechanical transmission to corresponding indicator plants. A total of 8000 seeds were tested. The incidence of virus diseases was confirmed on a considerable number of seedlings. A far greater percentage of bean lines cv. Improved Gradištanac were virus diseased compared with cv. Tetovac. Transmission ranged from 20% (cucumber mosaic virus) to 26% (bean common mosaic virus). Based on the results obtained it can be concluded that virus diseased bean seeds play a major role in further disease spread

Alpine thermal events in the central Serbo‑Macedonian Massif (southeastern Serbia)

The Serbo-Macedonian Massif (SMM) represents a crystalline belt situated between the two diverging branches of the Eastern Mediterranean Alpine orogenic system, the northeast-vergent Carpatho-Balkanides and the southwest-vergent Dinarides and the Hellenides. We have applied fission-track analysis on apatites and zircons, coupled with structural field observations in order to reveal the low-temperature evolution of the SMM. Additionally, the age and geochemistry of the Palaeogene igneous rocks (i.e. Surdulica granodiorite and dacitic volcanic rocks) were determined by the LA-ICPMS U–Pb geochronology of zircons and geochemical analysis of main and trace elements in whole-rock samples. Three major cooling stages have been distinguished from the late Early Cretaceous to the Oligocene. The first stage represents rapid cooling through the partial annealing zones of zircon and apatite (300–60 °C) during the late Early to early Late Cretaceous (ca. 110–ca. 90 Ma). It is related to a post-orogenic extension following the regional nappe-stacking event in the Early Cretaceous. Middle to late Eocene (ca. 48–ca. 39 Ma) cooling is related to the formation of the Crnook–Osogovo–Lisets extensional dome and its exhumation along low-angle normal faults. The third event is related to regional cooling following the late Eocene magmatic pulse. During this pulse, the areas surrounding the Surdulica granodiorite (36 ± 1 Ma) and the slightly younger volcanic bodies (ca. 35 Ma) have reached temperatures higher than the apatite closure temperature (120 °C) but lower than ca. 250 °C. The geochemistry of the igneous samples reveals late- to post-orogenic tectonic setting during magma generation