Viroze kukuruza - realna ekonomska opasnost ili samo neosnovan strah

Maize viral diseases can be found anywhere in the world where maize is grown. The most widely spread and harmful ones in the northern hemisphere in general and Yugoslavia in particular are two viruses of the genus Potyvirus, the Maize Dwarf Mosaic Potyvirus and Sugarcane Mosaic Potyvirus. In recent years, viruses that cause maize dwarf mosaic have been increasingly spreading in our country, where they have become a real economic threat. In some years that are favorable for the development of the virus vector and an abundance of the disease sources (Johnsongrass), outbreaks of maize dwarf mosaic reach epidemic proportions and cause huge amounts of damage by reducing the yields of commercial maize by about 20% and those of seed maize by about 70%. The disease symptoms manifest themselves in the form of striped white-yellowish mosaic that appears on the leaves. The growth of systemically infected plants is stunted. Diseased plants form short ears that sterile to a greater or lesser extent. The Maize Dwarf Mosaic Potyvirus and Sugarcane Mosaic Potyvirus are both elongated viruses with a single-strand infective ribonucleic acid (RNA). They belong to the genus Potyvirus of the Potyviridae family. These viruses parasitize around 200 other species from the Poaceae family in addition to maize and Johnsongrass. They are spread by 23 leaf aphid species, the most important among which are Rhopasosiphon maydis, Myzus persicae and some others. The biggest source of infection in the wild is Johnsongrass (Sorghum halepense). There are a number of measures, all of them preventive, that can help reduce the incidence of maize viral diseases and their harmfulness. They include the eradication of weeds that host the viruses, an earlier sowing, and the growing of less susceptible or tolerant hybrids. The most effective way to protect maize crops, minimize the damage, and prevent the incidence of these viruses is to develop genotypes that are resistant to the prevalent viruses in a given area. The results of studies on maize resistance to the Maize Dwarf Mosaic Potyvirus and Sugarcane Mosaic Potyvirus confirm the existence of sources of resistant genotypes (both domestic and foreign) that can be used as sources of desirable genes in maize breeding. Resistance to the Sugarcane Mosaic Potyvirus is controlled by two dominant genes Scm1 and Scm2, and so is resistance to the Maize Dwarf Mosaic Potyvirus (genes Mdm1 and Mdm2).Viroze kukuruza predstavljaju realnu ekonomsku opasnost kako u svetu tako i u našoj zemlji. Najznačajnija i ekonomski najopasnija viroza kukuruza je mozaična kržljavost. Ovo obolenje u našoj zemlji prouzrokuje virus mozaične kržljavosti kukuruza (maize dwarf mosaic potyvirus) i virus mozaika šećerne trske (sugarcane mosaic potyvirus). Ovi virusi poslednjih godina pokazuju sve veću ekspanziju širenja kod nas i predstavljaju veliku ekonomsku opasnost u proizvodnji kukuruza, smanjujući prinose merkantilnog kukuruza za oko 20% i semenskog za oko 70% u godinma povoljnim za širenje virusa. Najefikasniji način zaštite kukuruza i smanjenja štetnosti virusa je stvaranje otpornih genotipova prema prevalentnim virusima za dato područje. Utvrđeno je da postoje izvori otpornih genotipova, kako domaćeg tako i stranog porekla, koji se mogu koristiti kao izvori poželjnih gena u selekciji kukuruza. Otpornost prema virusima,prouzrokovačima mozaične kržljavosti je kontrolisana sa dva dominantna gena Mdm 1 i Mdm 2 a otpornost prema VMŠT takođe sa dva dominantna gena Scm 1 i Scm 2

Patogenost Fusarum vrsta na soji

The paper describes the symptoms of the Fusarium wilt and necrosis of root and lower stem of soybean, which include leaf chlorosis, wilt of the apical portion of the plant, necrosis of the root and lower stem, and wilting of the whole plant. The pods are often poorly developed. The seeds may be smaller and lighter in the weight and infected, as well. Isolated from diseased soybean plants were the species Fusarium avenaceum, F. equiseti, F. oxysporum and F. poae. Pathogenicity tests under artificial infection conditions showed F. oxysporum (isolate S/1) to be the most pathogenic among of the four investigated species. The other species proved much less pathogenic.Fuzariozna uvelost, nekroza korena i prizemnog dela stabla soje pojedinih godina se javlja i u našoj zemlji u većoj ili manjoj meri. Ovo oboljenje se intenzivnije javlja u godinama sa toplim i suvim letima, pogodnim za razvoj uvelosti soje, prouzrokovane vrstama iz roda Fusarium. Iz uzoraka obolelih biljaka sa simptomima oboljenja su izolovane i determinisane vrste Fusarium avenaceum, F. equiseti, F. oxysporum i F. poae. U ogledima sa veštačkom inokulacijom soje najveću patogenost ispoljavao je izolat S/1 F. oxysporum. F. oxysporum (S/1) je značajno smanjio klijavost i nicanje biljaka soje, a povećao broj trulih zrna. Ostale vrste ispoljile su znatno slabiju patogenost. Problemu fuzariozne uvelosti, nekroze korena i prizemnog dela stabla soje trebalo bi posvetiti veću pažnju zbog mogućnosti uvećanja značaja ovog oboljenja usled sve češće pojave toplih i suvih leta, povoljnih za razvoj bolesti

Vrste roda Diaporthe/Phomopsis na soji u Srbiji

A complex of soybean diseases is caused by species from the genus Diaporthe /Phomopsis. Diaporthe phaseolorum (anamorph Phomopsis phaseoli) and Phomopsis longicolla (teleomorph unknown) are described as soybean pathogens. The first species includes three varieties: D. phaseolorum var. sojae, anamorph Phomopsis sojae, the causal agent of pod and stem blight, and D. phaseolorum var. caulivora and D. phaseolorum var. meridionalis, agents of northern and southern stem canker. The species P. longicolla is the most common and most damaging agent of soybean seed decay. The diseases caused by parasites from this genus were first observed and described on soybean in the USA. Presently they are widespread in most soybean-growing regions around the world. Soybean in Serbia is attacked by all pathogens mentioned above, except for D. phaseolorum var. meridionalis, the causal agent of the southern stem canker. D. phaseolorum var. caulivora (northern stem canker) has the greatest economic importance because it causes wilt and drying of plants during pod development and grain filling. Most intensive outbreaks of the disease occurred in the 1980s in southern and southeastern Banat, southern Bačka and Srem. Prematurely wilted plants yielded 50% to 62% (depending on variety) less than healthy plants. Such heavy losses raised the question of the profitability of soybean growing. P. sojae and P. longicolla are less important in Serbia at the moment. Intensive infections of soybean seed break out occasionally. It was found that P. longicolla is the primary agent of seed decay and latent infections of seed in our country, although the other members of this genus may cause identical symptoms. Sexual cycle of development (teleomorph stage) of the fungi of the genus Diaporthe /Phomopsis form perithecia with asci and ascospores, while in the asexual cycle (anamorph stage) various types of conidia (α and β) are formed in pycnidia. The species P. longicolla has no teleomorph stage. Infected harvest residues and soybean seeds are main sources of the inoculum. D. phaseolorum var. caulivora forms perithecia with ascospores on overwintered harvest residues. During growing season, ascospores infect leaf laminas, petioles, or injured plant parts. P. sojae and P. longicolla form pycnidia (P. sojae sometimes forms perithecia), and they infect plants by means of conidia. Seed infection by conidia or ascospores unfolds via pods. Infected crop residues are the main source of the inoculum, while infected seeds help the parasites spread over large distances. Humidity and temperature (soil and air) are the mains factors that affect the dynamics of fruiting body formation, spore release, establishment of infection and the development of disease symptoms on soybean plants. Considerable attention is devoted to finding effective sources of resistance to the disease complex caused by species from the genus Diaporthe/Phomopsis. Resistance to the agents of seed decay was found in several introduced (PI) genotypes. This resistance is controlled by one or two pairs of dominant genes. Some cultivars are resistant to D. phaseolorum var. meridionalis (southern stem canker). Their resistance is controlled by two or four pairs of genes (Rdc). There is no physiological resistance to D. phaseolorum var. caulivora, the agent of northern stem canker, but significant differences in susceptibility level exist among soybean genotypes. Molecular techniques (RAPD, PCR-RFLP) showed that significant variability was present within the population of D. phaseolorum var. sojae. Other species of fungi were suspected to exist within that population, which could not be distinguished on the basis of their morphological characteristics. This was subsequently confirmed by the sequencing of different regions of ribosomal DNA.Kompleks oboljenja na soji izazivaju gljive iz roda Diaporthe/Phomopsis. Kao paraziti soje opisana su tri varijeteta vrste Diaporthe phaseolorum (anamorf Phomopsis phaseoli), i to: D. phaseolorum var. sojae (syn. P. sojae), prouzrokovač paleži mahuna i stabla (pod and stem blight), zatim D. phaseolorum var. caulivora i D. phaseolorum var. meridionalis prouzrokovači 'severnog' i 'južnog' tipa raka stabla (soybean stem canker). Phomopsis longicolla (teleomorf nepoznat) je najčešći prouzrokovač truleži semena (soybean seed decay), mada ovo oboljenje izazivaju i sva tri varijeteta gljive D. phaseolorum. Svi pomenuti pripadnici roda, izuzev D. phaseolorum var. meridionalis, prisutni su na soji u Srbiji, a najveći značaj ima D. phaseolorum var. caulivora, prouzrokovač raka stabla. Poslednjih nekoliko decenija sprovedena su brojna, sveobuhvatna proučavanja parazita roda Diaporthe/ Phomopsis na soji u našoj zemlji. Nedavno započeta istraživanja na molekularnom nivou ukazuju da su pored pomenutih na soji prisutne i druge vrste ovog roda. U ovom radu su analizirani rezultati višegodišnjih istraživanja u svetu i kod nas

Gljive iz roda Fusarium na semenu soje

The isolation of fungi of the genus Fusarium was done using seeds of the four most commonly grown soybean varieties in the Vojvodina Province: Afrodita, Ravnica, Balkan and Vojvođanka. The analysis of morphological and growth properties confirmed that the isolates belonged to the following species: Fusarium graminearum, F. semitectum, F. equiseti, F. sporotrichioides, F. acuminatum and F. proliferatum. Pathogenicity of the fungi of the genus Fusarium was tested on the sterile filter paper in the laboratory and the sterile substrate in the glasshouse. All isolates on the filter paper decreased germination and the germ length in the inoculated seeds, and they also caused seed necrosis at a very high percentage. In the greenhouse, all isolates caused greater or lesser deterioration of soybean seedlings and the occurrence of rotten seeds.Gljive roda Fusarium izolovane su iz semena četiri sorte soje: Afrodita, Ravnica, Balkan i Vojvođanka. Determinacija je izvršena na bazi morfoloških i odgajivačkih karakteristika pri čemu je utvrđeno da izolati pripadaju sledećim vrstama: F. graminearum, F. semitectum, F. equiseti, F. sporotrichioides, F. acuminatum i F. proliferatum. Provera patogenosti ovih gljiva je ispitana na sterilnom filter papiru u laboratoriji i u sterilnom supstratu u staklari. Na osnovu rezultata inokulacionih ogleda utvrđeno je da su svi izolati u manjoj ili većoj meri ispoljili patogenost prouzrokujući trulež semena, nekrozu klice i propadanje ponika ili zaostajanje biljaka u porastu

Soybean seed-borne fungal diseases in Vojvodina province

Numerous phytopathogenic microorganisms are associated with soybean seeds. Seed serves as a means of survival for pathogens and can provide primary inoculum for infected the new crop. The most significant and the most harmful are fungi. Soybean seed-borne diseases are present in Vojvodina province too. Occurrence of seed mycoflora is typically low, but intensive disease attacks may occur in some years. The aim of this paper was to determine the presence of phytopatogenic fungi on and in soyabean seed originating from 6 different seed companies in Vojvodina region. The following varieties most commonly used in production were tested: {2001-2002) 75 seed lots were tested. Fungi determination was done on the basis of morphological and growing characteristics. Presence of P. manshurica was determined by inspection of dry seeds. From soybean seeds were isolated fungi belonging to genera Diaporthe/ Phomopsis ( Phomopsis longicolla, D. p. var. caulivora and Phomopsis sojae) and Fusarium (F. graminearom, F. semitectum, F. equiseti, F. sporotrichoides, F. acuminatum and F. proliferatum). In most of the soybean seed samples fungi belonging to Al­ ternaria, Aspergilus and Penicillium genera were present. Besides above mentioned micoflora, a certain number of bacteria was also found on soybean seed, but they did not investigated further. Degree of soybean seed infection by parasitic mycoflora in both years of ob­ servation was relatively low. From 75 tested seed lots 11were free from parasitic fungi. Most of the samples had small percentage of seed infected by parasitic fungi (1-2%). Percentage of seed infection per sample with P. manshurica ranging from 1-53, Diaporthe/Phomopsis complex 1-113, and Fttsarium species 1-7%. Seed of Afrodita variety had the lowest percentage of infection, then comes Vojvodjanka, while Balkan and Ravnica varieties had the highest percentage of seed infection. Humidity, relatively high air temperature during maturation and harvesting time (August-Sepember) in 2001favoured intense appearance and distribution of para­ sites compared with the same extremely dry period in 2002 and significantly lower infection by parasitic fungi

Proučavanje crvenila kukuruza u Banatu

Corn reddening was observed for the first time in Serbia in 1957. After that, it occurred periodically, mainly in the region of Banat. In 2002 and 2003, severe corn reddening occurred in late July / early August. Initial symptoms were the occurrence of a red-violet color on the leaves, leaf sheaths, husks and the bare portion of internodes. The symptoms typically appeared at the milk stage of grain maturity, and the discoloration was the most intensive at top leaves, around the main vein and along the edges, from leaf base to tip. Soon after the occurrence of the symptoms, the affected plants wilted, the foliage dried rapidly, the red pigmentation disappeared for a greater part and finally plant died off. The ears were underdeveloped and gummous and kernels were shriveled and unfilled. Clashing opinions are still exists on what is the main cause of corn reddening.Crvenilo kukuruza je u Srbiji prvi put registrovano 1957. godine. Nakon toga, javljalo se periodično uglavnom u regionu Banata. Tokom 2002. i 2003. godine crvenilo kukuruza se pojavilo u jakom intenzitetu krajem jula, početkom avgusta. Inicijalni simptomi bili su pojava crveno-ljubičaste boje listova, lisnih rukavaca, ovojnih listova klipa i otkrivenih delova internodija. Simptomi su se uglavnom javljali u fazi mlečne zrelosti s tim da je najintenzivnija pojava crvene boje bila na gornjim listovima, oko glavnog nerva i uzduž ivica listova od osnove prema vrhu. Nakon pojave prvih simptoma, biljke su ubrzo počinjale da venu, lisna masa da se suši, crvena pigmentacija nestaje i konačno biljke su uginjavale. Klipovi biljaka zahvaćenih crvenilom su bili nerazvijeni, gumozni sa smežuranim i nenalivenim zrnom. Još uvek postoje oprečna mišljenja o tome šta je glavni prouzrokovač crvenila

Examination of seminal qualities of oilseed rape (Brassica napus L.) treated with insecticides and fungicides

Uljana repica se uzgaja na velikim površinama u svijetu, a u posljednjem desetljeću zabilježen je i značajan rast površina u području jugoistočne Europe. Najčešće se siju nove sorte u tipu kvalitete “00” bez eruka kiseline i niskog sadržaja glukozinolata. Konstantan je porast površina pod sjemenskom uljanom repicom. Tretiranje sjemena uljane repice insekticidima i fungicidima koristi se u sve većoj mjeri kao ekološki i ekonomski prihvatljiviji vid kemijskog suzbijanja bolesti i štetnih kukaca u ranoj fazi vegetacije. U radu je ispitivan utjecaj različitih kombinacija fungicida i insekticida na klijavost sjemena sorte Banaćanka, nakon 15 mjeseci i 21 mjesec skladištenja od dana tretiranja. Klijavost i energija klijanja testirani su na filter papiru, a životna sposobnost sjemena na smjesi perlita i pijeska. Korišteno je šest najzastupljenijih pripravaka u doradi sjemena. Dužina skladištenja izazvala je pad sjemenskih kvaliteta kod svih kombinacija pesticida, kao i kod netretirane varijante. Na osnovu rezultata istraživanja izdvojene su formulacije pesticida i njihove koncentracije koje nisu pokazale negativan utjecaj na sjemenske kvalitete.Oil seed rape is cultivated on great areas in the world, and in the last decade, a significant growth of the sown areas in the region of south east Europe was recorded. New sorts in quality type “00” without eruca acid and a low content of glucosinolate are most frequently sown. The growth of areas under seminal oilseed rape is constant. The treatment of oilseed rape with insecticides and fungicides has been highly used as ecologically and economically acceptable way in chemical control of disease and harmful insects in early stage of vegetation. The review has examined the effect of different combinations of fungicides and insecticides on seed germination of Banacanka sort after 15 and 21 months of storage, from the day of treatment. Germination and energy of germination have been tested on filter paper, and life ability of seed has been tested on mixture of perlite and sand. Six most represented preparations in seed processing have been used. Storage length caused decline of seminal quality with all pesticide combinations as well as with the untreated variety. Based on research results, pesticide formulations and their concentrations which haven’t shown a negative effect on seminal qualities have been singled out

Istorijski razvoj biljne virusologije u Srbiji

Otkriće biljnih virusa vezuje se za 1898. godinu kada je Martinus Willem Beijerinck proučavajući mozak duvana ukazao na novi svet infektivnih agenasa („contagium vivum fluidum“). U Srbiji tridesetih godina prošlog veka, proučavanja biljnih virusa započela su naučnim radom Mladena Josifovića na šarki šljive. Posle Drugog svetskog rata, Dragoljub Šutić, Veljko Nikolić i Mitar Jordović uvode naučne eksperimentalne metode u istraživanja viroza, i time postavljaju temelje razvoja proučavanja biljnih virusa kod nas. Razvoj virusologije u Srbiji, kao i u većini zemalja, obuhvatao je nekoliko faza: početnu deskriptivnu (otkrivanje i opisivanje brojnih viroza), potom epidemiološku (proučavanje načina održavanja i širenja virusa), fizičko-hemijsku (proučavanje morfoloških osobina i hemijskog sastava virusa), molekularno-biološku fazu (razumevanje strukture i funkcije genoma virusa, mehanizama replikacije, unapređenje starih i uvođenje novih metoda detekcije i identifikacije virusa i njihovih sojeva, pravilna taksonomija virusa u skladu sa poreklom i evolutivnim međuodnosima)

Bolesti semena soje

Numerous phytopathogenic microorganisms cause soybean seed diseases which negatively affect seed yield and quality. In turn, seed serves as a vehicle to transmit parasites from year to year and from location to location. Phytopathogenic fungi are most numerous and most harmful agents of soybean seed diseases. Seed parasites are present on soybeans in Serbia too, but the intensity of their occurrence is typically low. Intensive disease attacks and large damage occur only in some years. The most frequent disease is downy mildew caused by Peronospora manshurica. Direct damage to soybean seed is insignificant, but use of infected seed causes the occurrence of systemically infected plants resulting in secondary leaf infections. Parasites from the genus Diaporthe/Phomopsis (P. longicolla, P. sojae, D. Phaseolorum var. caulivora) gain increasing importance. They cause seed rot and latent infections. Continued periods of high air humidity and temperature at the time of soybean maturation favor the outbreak and spread of seed rot symptoms. Intensive attacks of purple seed stain (Cercospora kikuchii) and anthracnose (Colletotrichum spp) occur periodically in our country. Correct cultivation practices such as the strict adherence to crop rotation, use of less susceptible or resistant varieties in infection-prone regions, use of healthy seed, removal of harvest residues, etc. are typically recommended for control of soybean seed diseases. Chemical measures of disease control are not common. They are used on certain occasions, mostly in seed crops. Such crops are typically treated at the stages of seed forming and filling.Daje se kraći pregled najznačajnijih parazita semena soje u Srbiji. Obrađena je njihova rasprostranjenost, ekonomski značaj, simptomi, biološke i epidemiološke karakteristike, kao i mogućnosti suzbijanja. Nabrojane su i ostale parazitne gljive od manjeg ekonomskog značaja, koje mogu parazitirati seme soje ili se njime prenositi

Rasprostranjenost Diaporthe/Phomopsis vrsta na semenu soje u Srbiji

Soybean seed samples were analyzed for the presence of seed borne fungi from the genus Diaporthe/Phomopsis in the period 2002-2004. The samples were collected following a geographical principle, from large-plot trials located in the main soybean-growing regions of Serbia. The study included four soybean cultivars from different maturity groups: Afrodita (O), Balkan (I), Vojvođanka (II) and Morava (III). Isolation on nutritive medium (PDA) and determination of the isolated fungi were performed using conventional phytopathological methods. it was shown that parasites from the genus Diaporthe/Phomopsis were present in most soybean-growing regions of Serbia. Intensity of seed infection varied considerably depending on year and location. For example, an intensive infection (over 65% in some samples) was registered in 2002, while very weak infection was found in 2003 (Tables 1, 2 and 3). Large differences were found between disease intensities per location in the same year. The year 2002 was characteristic i-that respect, with no infection on several locations and high percentage of infected seed on others. Obviously, the intensity of seed infection with fungi from the genus Diaporthe/Phomopsis is determined mostly by weather conditions. Continual high air humidity and temperature from the beginning of soybean maturation till harvest encourage the infection and development of seed decay. Accordingly, high infection rates were registered in the rainy year of 2002 and in humid regions, especially along large rivers. The presence of two varieties of the fungus Diaporthephaseolorum, i.e., D. phaseolorum var. caulivora, the agent of soybean stem canker, and D. phaseolorum var. sojae, anamorph Phomopsis sojae, the agent of pod and stem blight, as well as of the species Phomopsis longicolla, the agent of soybean seed decay, was confirmed in the analyzed seed samples. These pathogens had already been reported on soybean seeds in Serbia. The intensity of their occurrence depends on year, location and cultivar (Figs. 1, 2 and 3). For example, D. phaseolorum var. caulivora predominated in 2002, P. longicolla in 2003 and P. sojae in 2004. On the three-year average, the presence of these seed pathogens was fairly uniform (Fig. 3).Tokom trogodišnjeg perioda (2002 - 2004. godine) analizirani su uzorci semena soje na prisustvo parazita iz roda Diaporthe/Phomopsis. Uzorci su prikupljeni po geografskom principu, iz sortnih makroogleda lociranih u glavnim regionima gajenja soje u Srbiji, istraživanjima su obuhvaćene četiri sorte različitih grupa zrenja; Afrodita (0), Balkan (l), Vojvođanka (II) i Morava (III). Izolacije na hranljivu podlogu (PDA) i determinacija izolovanih gljiva vršene su uobičajenim fitopatološkim metodama. Pokazalo se da su paraziti ovog roda prisutni u većini regiona gajenja soje u Srbiji. Intenzitet infekcije semena znatno varira u zavisnosti od godine i lokaliteta. Tako je u 2002. godini konstatovana veoma jaka zaraza (preko 65%, u pojedinim uzorcima), dok se u sledećoj, 2003. godini, pojavila samo u tragovima (tabele 1, 2 i 3). Međutim, evidentne su velike razlike u intenzitetu pojave oboljenja između pojedinih lokaliteta, u istoj godini. Karakterističan primer je 2002. godina, kada na nekoliko lokaliteta nije bilo infekcije semena, dok je na drugim procenat zaraženih zrna vrlo visok. Očigledno je da intenzitet infekcije semena parazitima iz roda Diaporthe/Phomopsis u najvećoj meri opredeljuju vremenski uslovi. Naime, utvrđeno je da kontinuirana vlažnost i povišena temperatura vazduha, od početka sazrevanja useva do žetve soje veoma pogoduju nastanku infekcije i širenju truleži semena. Shodno tome, potpuno je razumljivo da u kišovitoj 2002. godini, kao i humidnijim regionima koji gravitiraju većim rekama, intenzitet infekcije bude najjači. Iz analiziranih uzoraka semena izdvojena su dva varijeteta gljive: Diaporthe phaseolorum, i to: D. phaseolorum var. caulivora, prouzrokovač raka stabla soje i D. phaseolorum var. sojae, anamorf Phomopsis sojae, prouzrokovač paleži mahuna i stabla, kao i vrsta Phomopsis longicolla, prouzrokovač truleži semena. Svi pomenuti i paraziti već su ranije opisani na semenu soje u Srbiji. Zastupljenost navedenih vrsta varira u zavisnosti od godine, lokaliteta i sorte (Slike. 1,2 i 3). Tako je u 2002. godini najčešće izolovana D. Phaseolorum var. caulivora, u 2003. - R longicolla, a u 2004. godini P sojae. U prošeku za tri godine zastupljenost navedenih patogena semena je prilično ujednačena (Slika 3)