Spatial distribution of benzimidazole resistance of Cercospora beticola Sacc. in Serbia

In order to check distribution of resistance of C. beticola isolates to benzimidazole fungicides we collected samples from four distinct geographical districts with different fungicides history in Serbia. From all localities about 40 - 50 isolates of C. beticola were collected and subjected to testing sensitivity to benzimidazoles in the laboratory. Due to RG of isolates on the discriminatory concentrations of carbendazim and thiophanate methyl we concluded level of resistance to benzimidazoles. Discriminatory concentration for carbendazim was 1 mg/l while for thiophanate methyl was 5 mg/l. Very high frequency of resistance of C. beticola isolates to benzimidazole fungicides on locality West Bačka (98 %), Srem (100%) and Moravica (97%), while on locality Rasina decrease frequency of benzimidazole resistance with 18% was established. Frequency of resistance of C. beticola populations to benzimidazoles was stable on locality where benzimidazoles were applied in the past, while on locality where they have never been applied it varies

Spatial distribution of benzimidazole resistance of Cercospora beticola Sacc. in Serbia

In order to check distribution of resistance of C. beticola isolates to benzimidazole fungicides we collected samples from four distinct geographical districts with different fungicides history in Serbia. From all localities about 40 - 50 isolates of C. beticola were collected and subjected to testing sensitivity to benzimidazoles in the laboratory. Due to RG of isolates on the discriminatory concentrations of carbendazim and thiophanate methyl we concluded level of resistance to benzimidazoles. Discriminatory concentration for carbendazim was 1 mg/l while for thiophanate methyl was 5 mg/l. Very high frequency of resistance of C. beticola isolates to benzimidazole fungicides on locality West Bačka (98 %), Srem (100%) and Moravica (97%), while on locality Rasina decrease frequency of benzimidazole resistance with 18% was established. Frequency of resistance of C. beticola populations to benzimidazoles was stable on locality where benzimidazoles were applied in the past, while on locality where they have never been applied it varies

Optimalni rokovi primene fungicida za suzbijanje Podosphaera leucotricha, prouzrokovača rđaste mrežavosti plodova breskve u Srbiji

Peach rusty spot has regularly occurred in Serbia in recent years, causing significant economic losses in the production of late maturing cultivars (Summerset, Suncrest, Fayette and O’Henry). Concerns regarding the etiology of this disease have been solved using molecular identification and cross-pathogenicity tests, which have proved that peach rusty spot is caused by Podosphaera leucotricha. The usual recommended strategy for its control, by multiple treatments starting from petal fall phenophase, has not proved satisfactory in agro-ecological conditions in Serbia. After testing the fungicide efficacy, a three-year study was carried out to determine the precise treatment terms and make the control of P. leucotricha more efficient. The investigation was conducted in the conditions of natural infection in a Summerset cultivar orchard at the locality of Bela Crkva, during the period 2006-2008. Nine different variants of both single and mixed treatments were tested, covering six defined peach growth phenophases - from green top, until the phenophase of second fruit falling. In the conditions of high levels of natural infection in the control plots, in all three investigation years the most efficient was the variant in which kresoxim-methyl was applied three times: in green top, pink bud and full bloom phenophases (91.69 - 91.92%), followed by the variant of treatments in the phenophases of rose bud, full bloom and petal fall (86.3-87.87%) and the variant of two treatments, performed in the phenophases of pink bud and full bloom (79.3-83.09%). The other tested variants showed significantly lower efficiency. The results obtained could significantly contribute to better peach fruit production, without losses caused by peach rusty spot which is commercially very important disease in Serbia.Rđasta mrežavost plodova breskve poslednjih godina u Srbiji redovno se javlja i u proizvodnji poznih sorti (Summerset, Suncrest, Fayette i O’Henry) nanoseći značajne ekonomske gubitke. Nedoumice u pogledu etiologije ove bolesti razrešene su na osnovu molekularne identifikacije i unakrsnih testova patogenosti čime je dokazano da rđastu mrežavost breskve izaziva Podosphaera leucotricha. Strategija kontrole P. leucotricha primenjena u svetu, po kojoj suzbijanje treba sprovoditi u višekratnim tretmanima od fenofaze precvetavanja, nije dala zadovoljavajuće rezultate u agroekološkim uslovima Srbije. Nakon izvršenih ispitivanja efikasnosti fungicida, obavljeno je trogodišnje istraživanje u cilju određivanja preciznih rokova tretiranja breskve radi uspostavljanja efikasne kontrole P. leucotricha. Ispitivanje je obavljeno u periodu od 2006. do 2008. godine, u zasadu breskve sorte Summerset, u uslovima prirodne zaraze na lokalitetu Bela Crkva. Testirano je devet različitih varijanti, koje su se sastojale iz kombinovanih i pojedinačnih tretiranja, tako da je pokriven period od šest definisanih fenofaza razvoja breskve, počevši od fenofaze zeleni vrh do fenofaze drugo opadanje plodova. U uslovima visokog nivoa prirodne zaraze u kontrolnim parcelama, najvišu efikasnost u sve tri godine ispitivanja ispoljila je varijanta u kojoj je kresoksim- metil primenjivan tri puta, u fenofazi zeleni vrh, roze pupoljak i cvetanje (91,69-91,92%), odmah zatim varijanta u kojoj su izvođeni tretmani u fenofazi roze pupoljak, cvetanje i precvetavanje (86,3-87,87%) i varijanta u okviru koje su bila vršena dva tretmana u fenofazi roze pupoljak i cvetanje (79,3-83,09%). Ostale varijante u ogledu ispoljile su znatno nižu efikasnost. Dobijeni rezultati značajno doprinose poboljšanom načinu proizvodnje breskve bez gubitaka izazvanih rđastom mrežavosti ploda, ekonomski sve značajnijeg oboljenja u Srbiji

Optimalni rokovi primene fungicida za suzbijanje Podosphaera leucotricha, prouzrokovača rđaste mrežavosti plodova breskve u Srbiji

Peach rusty spot has regularly occurred in Serbia in recent years, causing significant economic losses in the production of late maturing cultivars (Summerset, Suncrest, Fayette and O'Henry). Concerns regarding the etiology of this disease have been solved using molecular identification and cross-pathogenicity tests, which have proved that peach rusty spot is caused by Podosphaera leucotricha. The usual recommended strategy for its control, by multiple treatments starting from petal fall phenophase, has not proved satisfactory in agro-ecological conditions in Serbia. After testing the fungicide efficacy, a three-year study was carried out to determine the precise treatment terms and make the control of P. leucotricha more efficient. The investigation was conducted in the conditions of natural infection in a Summerset cultivar orchard at the locality of Bela Crkva, during the period 2006-2008. Nine different variants of both single and mixed treatments were tested, covering six defined peach growth phenophases - from green top, until the phenophase of second fruit falling. In the conditions of high levels of natural infection in the control plots, in all three investigation years the most efficient was the variant in which kresoxim-methyl was applied three times: in green top, pink bud and full bloom phenophases (91.69 - 91.92%), followed by the variant of treatments in the phenophases of rose bud, full bloom and petal fall (86.3-87.87%) and the variant of two treatments, performed in the phenophases of pink bud and full bloom (79.3-83.09%). The other tested variants showed significantly lower efficiency. The results obtained could significantly contribute to better peach fruit production, without losses caused by peach rusty spot which is commercially very important disease in Serbia.Rđasta mrežavost plodova breskve poslednjih godina u Srbiji redovno se javlja i u proizvodnji poznih sorti (Summerset, Suncrest, Fayette i O'Henry) nanoseći značajne ekonomske gubitke. Nedoumice u pogledu etiologije ove bolesti razrešene su na osnovu molekularne identifikacije i unakrsnih testova patogenosti čime je dokazano da rđastu mrežavost breskve izaziva Podosphaera leucotricha. Strategija kontrole P. leucotricha primenjena u svetu, po kojoj suzbijanje treba sprovoditi u višekratnim tretmanima od fenofaze precvetavanja, nije dala zadovoljavajuće rezultate u agroekološkim uslovima Srbije. Nakon izvršenih ispitivanja efikasnosti fungicida, obavljeno je trogodišnje istraživanje u cilju određivanja preciznih rokova tretiranja breskve radi uspostavljanja efikasne kontrole P. leucotricha. Ispitivanje je obavljeno u periodu od 2006. do 2008. godine, u zasadu breskve sorte Summerset, u uslovima prirodne zaraze na lokalitetu Bela Crkva. Testirano je devet različitih varijanti, koje su se sastojale iz kombinovanih i pojedinačnih tretiranja, tako da je pokriven period od šest definisanih fenofaza razvoja breskve, počevši od fenofaze zeleni vrh do fenofaze drugo opadanje plodova. U uslovima visokog nivoa prirodne zaraze u kontrolnim parcelama, najvišu efikasnost u sve tri godine ispitivanja ispoljila je varijanta u kojoj je kresoksim- metil primenjivan tri puta, u fenofazi zeleni vrh, roze pupoljak i cvetanje (91,69-91,92%), odmah zatim varijanta u kojoj su izvođeni tretmani u fenofazi roze pupoljak, cvetanje i precvetavanje (86,3-87,87%) i varijanta u okviru koje su bila vršena dva tretmana u fenofazi roze pupoljak i cvetanje (79,3-83,09%). Ostale varijante u ogledu ispoljile su znatno nižu efikasnost. Dobijeni rezultati značajno doprinose poboljšanom načinu proizvodnje breskve bez gubitaka izazvanih rđastom mrežavosti ploda, ekonomski sve značajnijeg oboljenja u Srbiji

Sličnosti i razlike u molekularnom paternu ITS regiona nekih Globodera rostochiensis populacija

Evolutionary relationships of organisms in the past are based on morphological, biogeographical, and paleontological data. The emergence of molecular tools has enabled the study of the genetic structure of organisms and study of their phylogeny using protein or nucleotide sequences, which is especially important for organisms such as cyst nematodes that have no fossil records and are morphologically very similar. This paper presents molecular characterization of some G. rostochiensis populations in our region based on molecular pattern of ITS region. Molecular characterization of the studied populations showed similarities with the previously characterized populations but also some differences.Evolutivni odnosi organizama u prošlosti su zasnivani na morfološkim, biogeografskim i paleontološkim podacima. Pojava molekularnih alata omogućila je izučavanje genetičke strukture organizama i proučavanje njihove filogenije uz pomoć proteinskih ili nukleotidnih sekvenci, što je posebno značajno kod organizama kao što su cistolike nematode koje nemaju fosilnih ostataka a morfološki su veoma slične. U ovom radu je data molekularna karakterizacija nekih populacija G.rostochiensis sa naših prostora u molekularnom paternu ITS regiona. Molekularna karakterizacija ispitivanih populacija je pokazala sličnosti ispitivanih populacija sa već ranije okarakterisanim populacijama ali i neke razlike

Učestalost rezistentnosti Cercospora beticola (Sacc.) prema benzimidazolima i DMI fungicidima

Cercospora leaf spot is the most important disease that occurs on sugar beet in the world. Damages caused by this disease can reduce yields up to 50 %. Resistance to the group of benzimidazole fungicide was determined in 1976. Last twenty years their use has been reduced but they're still used, mainly formulated in mixture with fungicides - sterol demethylation inhibitors (DMI). Sterol demethylation inhibitors (DMI) have been used extensively in the last two decades to control C. beticola in the world, and resistance to them was observed in 2000. The results showed that populations of C. beticola resistant to benzimidazole are present in sugar beet fields and are the dominant population, with the prevalence of resistance 83.87 - 94.28 %. The frequency of resistance to DMI fungicides is smaller, but highly significant and amounts to 12.90 - 14.29 %.Pegavost lišća šećerne repe je najznačajnija bolest koja se javlja na šećernoj repi u svetu. Štete koje nastaju usled pojave bolesti mogu smanjiti prinos i do 50%. Prema fungicidima iz grupe benzimidazola rezistentnost je utvrđena 1976. godine. Poslednjih dvadeset godina njihova upotreba je redukovana, ali se i dalje koriste uglavnom formulisani u mešavini sa fungicidima inhibitorima sinteze sterola (DMI). Fungicidi inhibitori demetilacije sterola (DMI), se zadnje dve decenije intenzivno koriste za suzbijanje C. beticola u svetu, a pojava rezistentnosti prema njima konstatovana je 2000. godine. Rezultati istraživanja su pokazali da su populacije C. beticola rezistentne prema benzimidazolima prisutne na poljima šećerne repe i čine dominantnu populaciju uz učestalost rezistentnosti 83.87 - 94.28 %. Učestalost rezistentnosti prema DMI fungicidima je manja, ali veoma značajna i iznosi 12.90 - 14.29 %

Morfološka i molekularna identifikacija Colletotrichum acutatum sa ploda paradajza

Colletotrichum gloeosporioides, Colletotrichum acutatum, Colletotrichum coccodes, and Colletotrichum dematium are the four main species of Colletotrichum that cause tomato anthracnose. In Serbia, the occurrence of anthracnose on tomato fruit has been recorded during the last several years. Typical fruit symptoms include dark, sunken, and circular lesion with orange conidial masses. Pathogen isolates were obtained from a diseased tomato fruits, on PDA medium forming a white to gray colonies. The cultures developed black acervuli around the center of the colony. Conidia were hyaline, aseptate, and fusiform or rarely cylindrical. Appressoria were smooth, simple, clavate to ovate, and varied from light to dark brown. Pathogenicity tests with representative isolates were conducted on symptomless, detached tomato fruits. All tested isolates caused anthracnose lesions on tomato fruit after 7 days of incubation. Koch's postulates were fulfilled by reisolation from inoculated tomato fruits. PCR analysis (using species-specific primer pair, CaInt2/ ITS4) of genomic DNA from tomato isolates resulted in an amplification product of 490 bp, specific for C. acutatum, further confirming the identity of the pathogen. Based on morphological and molecular characteristics, the isolates from tomato fruit were determined as C. acutatum.Četiri glavna prouzrokovača antraknoze paradajza iz roda Colletotrichum su: Colletotrichum gloeosporioides, Colletotrichum acutatum, Colletotrichum coccodes i Colletotrichum dematium. U Srbiji je tokom poslednjih godina zabeležena pojava antraknoze ploda paradajza. Tipični simptomi na plodu su tamne, ulegnute, kružne lezije sa masom narandžastih konidija. Sa obolelih plodova paradajza dobijeni su izolati patogena koji na KDA podlozi obrazuju bele do sivo obojene kolonije. Acervuli crne boje formiraju se u kulturi oko centra kolonije. Konidije su hialinske, neseptirane, fusiformne ili ređe cilindrične. Apresorije su glatke, jednostavne, okruglastog ili oblika izdužene palice, svetlo do tamno braon boje. Test patogenosti je obavljen sa reprezentativnim izolatima, na odabranim, zdravim plodovima. Svi ispitivani izolati prouzrokuju antraknozne lezije na plodu paradajza 7 dana nakon inokulacije. Kohovi postulati su zadovoljeni reizolacijama sa inokulisanih plodova paradajza. PCR analiza (korišćenjem para prajmera specifičinog za vrstu, CaInt2/ITS4) iz genoma DNA izolata sa paradajza rezultirala je amplifikacijom produkta od 490 bp, specifičnog za C. acutatum, što je potvrdilo identitet patogena. Na osnovu morfoloških i molekularnih karakteristika izolati sa ploda paradajza determinisani su kao C. acutatum

Efikasnost rokova primene fungicida za suzbijanje Taphrina deformans, prouzrokovača kovrdžavosti lista breskve u Srbiji

The causal agent of peach leaf curl Taphrina deformans, in recent years in Serbia occurs regularly and causes significant economic losses. As the leaf curl important in many areas of growing peaches in the world, great attention is focused on finding a measure of control. According to recommendations from the literature sources of chemical protection against this pathogen should be carried out in several treatments, ie. in the fall after the leaves fall and the spring just before and during the swelling buds. As is well known that the pathogen T. deformans infection achieved solely through the undifferentiated tissue swelling in the bud stage of development, there were determined the effectiveness of fungicides recommended in all phenological stages of development. The study was conducted during fall 2006. and spring of 2007. year, the Summerset peach orchards cultivars in conditions of natural infection at the site of Bela Crkva. We tested seven different varieties, which are comprised of individual and combined treatments, so that the period covered by the three defined phenological stages of peach, starting from autumn treatment stage of development in 50% of leaves yellow and dorman and growth stages of vegetation where the applied fungicide copper hidroksid, and phenophase bud swell to when fungicide was applied ziram. In conditions of high levels of natural infection in the control plots, the highest efficiency demonstrated the variant that contained the treatment of swelling in the bud stage of development (96.22 - 97.84%), while other variants did not show satisfactory efficiency (7.78 - 16.85% ). These results significantly contribute to an improved method of groweing peach with substantial savings on chemicals without losses caused by disease, peach leaf curl.Prouzrokovač kovrdžavosti lista breskve Taphrina deformans, poslednjih godina u Srbiji redovno se javlja i nanosi značajne ekonomske gubitke. Kako je kovrdžavost lista značajna u mnogim područjima gajenja breskve u svetu velika pažnja usmerena je na iznalaženje mera kontrole. Prema preporukama iz literaturnih izvora hemijsku zaštitu protiv ovog patogena treba sprovoditi u nekoliko tretmana, tj. u jesen nakon opadanja lišća i u proleće neposredno pre i u toku bubrenja pupoljaka. Kako je poznato da patogen T. deformans ostvaruje infekciju isključivo preko nediferenciranog tkiva u fenofazi bubrenja pupoljka, vršena su ispitivanja efikasnosti primene fungicida u svim preporučenim fenofazama razvoja. Ispitivanje je obavljeno u periodu jesen 2006. i proleće 2007. godine, u zasadu breskve sorte Summerset, u uslovima prirodne zaraze na lokalitetu Bela Crkva. Testirano je sedam različitih varijanti, koje su se sastojale iz kombinovanih i pojedinačnih tretiranja, tako da je pokriven period od tri definisane fenofaze razvoja breskve, počevši od jesenjeg tretmana u fenofazi 50% lišća žuto i opalo i fenofaze mirovanja vegetacije gde je primenjen fungicid bakar hidroksid do fenofaze bubrenje pupoljka kada je primenjen fungicid ciram. U uslovima visokog nivoa prirodne zaraze u kontrolnim parcelama, najvišu efikasnost ispoljile su varijante koje su sadržale tretman u fenofazi bubrenja pupoljka (96,22 - 97,84%), dok ostale varijante nisu pokazale zadovoljavajuću efikasnost (7,78 - 16,85%). Dobijeni rezultati značajno doprinose poboljšanom načinu proizvodnje breskve uz značajnu uštedu hemijskih sredstava bez gubitaka izazvanih oboljenjem kovrdžavosti lista breskve

Identifikacija rasa Pseudomonas savastanoi pv. phaseolicola na domaćim sortama pasulja

Halo blight caused by the phytopathogenic bacterium Pseudomonas savastanoi pv. phaseolicola is economically important disease of bean in our area. In the present study, the pathogen was isolated from the leaves of the diseased bean plants, with the leaf samples having been collected from cultivars Oplenac, Slavonski žutozeleni and Zlatko using a nutrient agar (NA) and the medium enriched with 5% sucrose (NSA). Pathogenicity of the obtained isolates was proved by inoculation of young bean pods and by hypersensitive reaction (HR) on tobacco and geranium leaves. Biochemical and physiological characteristics were tested by conventional phytobacteriological methods. The race identity of the isolates was determined using a differential set of Phaseolus spp.: Canadian Wonder, ZAA54 (A52), Tendergreen, Red Mexican U13, 1072 P. acutifolius, ZAA55 (A53), ZAA12 (A43) i Guatemala 196-B). Inoculation was performed with atomizer, by spraying of bacterial suspension onto the undersurface of primary leaves. Obtained results indicated that strains showed the most similarity to race 1 of this bacterium.Oreolna plamenjača pasulja čiji je prouzrokovač fitopatogena bakterija Pseudomonas savastanoi pv. phaseolicola ekonomski je štetno oboljenje ove gajene kulture kod nas. U ovom radu vršena je izolacija patogena iz obolelog lišća pasulja sorti Oplenac, Slavonski žutozeleni i Zlatko na hranljivi agar (NA) i podlogu obogaćenu saharozom (NSA). Patogenost izolata je dokazana infiltracijom bakterijske suspenzije u mlade mahune boranije i pozitivnom hipersenzitivnom reakcijom (HR) na listu duvana i muškatle. Biohemijsko-fiziološke odlike ispitane su standardnim bakteriološkim metodama. Pripadnost dobijenih izolata fiziološkim rasama određena je korišćenjem diferencijalnog sortimenta Phaseolus spp.: Canadian Wonder, ZAA54 (A52), Tendergreen, Red Mexican U13, 1072 P. acutifolius, ZAA55 (A53), ZAA12 (A43) i Guatemala 196-B. Inokulacija je vršena atomizerom, prskanjem naličja primarnog lišća bakterijskom suspenzijom. Dobijeni rezultati ukazuju na najveću sličnost izolata sa rasom 1 ove bakterije

Osetljivost izolata Cercospora beticola prema karbendazimu i flutriafolu u Srbiji

The sensitivity of 110 Cercospora beticola (Sacc.) isolates to carbendazime (benzimidazoles) and flutriafol (triazole DMI) was investigated. Isolates on PDA were obtained from diseased sugar leaves collected in 11 localities in Serbia during the August 2007. The medium effective concentration (EC50), the relative sensitivity (b) and the level of resistance (NR) in relation to the most sensitive isolate were calculated the method applied by Karaoglanidis et al. (2000). The obtained results confirmed already resistance of Serbian isolates of C. beticola to carbendazime, but for the first time isolates from Erdevik and Maradik showed a significantly decreased sensitivity to flutriafol.Ispitivana je osetljivost izolata Cercospora beticola (Sacc.), prouzrokovača pegavosti lišća šećerne repe iz 11 lokaliteta u Srbiji prema karbendazimu (grupa benzimidazola) i flutriafolu (grupa triazola DMI) tokom 2007. godine. Uzorkovanje je obavljeno tokom avgusta meseca. Za ispitivane izolate izračunate su srednje efektivne koncentracije (EC50), relativna osetljivost (b) i nivo rezistentnosti (NR) u odnosu na najosetljiviji izolat, po metodi Karaoglanidis i sar. (2000). Dobijeni rezultati su potvrdili već ranije dokazanu rezistetnost izolata C. beticola poreklom iz Srbije na karbendazim, ali po prvi put i značajno smanjenu osetljivost izolata poreklom iz Erdevika i Maradika prema flutriafolu