Uticaj tretmana micelije ('semena') šampinjona (Agaricus bisporus L.) - bakterijom Bacillus subtilis QST713 na prinos i zaštitu od zelene plesni

A biofungicide based on Bacillus subtilis QST713 was tested for impact on yield and efficacy against a Trichoderma aggressivum f. europaeum T77 strain from Serbia by coating mushroom grain spawn and comparing the results with the chemical fungicide prochloraz manganese in a mushroom growing room. The tested B. subtilis QST713 strain did not inhibit mycelial growth of Agaricus bisporus in plots free of the pathogen, showing an impact on yield of 91.95%, which was not significantly different from an untreated control. As for the efficacy of the fungicides used against T. aggressivum f. europaeum T77, there were no significant differences between a prochloraz manganese casing treatment, and B. subtilis QST713 coating on mushroom grain spawn, as the efficacy was 70.37 and 53.09%, respectively. These results implied that the biofungicide based on B. subtilis could serve as a harmless alternative to synthetic fungicides in mushroom production, especially during serious compost green muold outbreaks caused by T. aggressivum. Furthermore, the biofungicide should be applied alone because an antagonistic reaction was detected between the fungicide prochloraz and B. subtilis QST713.Biofungicid na bazi Bacillus subtilis QST713 je odabran za testiranje uticaja na prinos i efikasnosti u suzbijanju Trichoderma aggressivum f. europaeum T77 iz Srbije, kada je primenjeno za tretiranje micelije ('semena') šampinjona u poređenju sa fungicidom prohloraz manganom u oglednom gajilištu. Testirani soj B. subtilis QST713 nije inhibirao rast micelije Agaricus bisporus, u tretmanima bez prisustva patogena, sa uticajem na prinos 91.95% i nije se statistički značajno razlikovao od neinokulisane kontrole. U pogledu efikasnosti fungicida u suzbijanju T. aggressivum f. europaeum T77, nije bilo statistički značajne razlike među tretmanima sa fungicidom prohloraz manganom primenjenim na pokrivku i tretmanom B. subtilis QST713 primejenim na miceliju ('seme') šampinjona, sa odgovorajućim vrednostima 70.37 i 53.09%. Ovi rezultati ukazuju da se biofungicid na bazi B. subtilis može primenjivati kao alternativa sintetičkom fungicidu u proizvodnji šampinjona, posebno kod značajne pojave zelene plesni u kompostu za gajenje šampinjona koju izaziva T. aggressivum. Takođe, preporuka je da se biofungicid primenjuje samostalno jer je uočena antagonistička reakcija između prohloraz mangana i B. subtilis QST713

Efikasnost biofungicida Polyversum™ u suzbijanju Botrytis cinerea Pers. na plodovima maline

Efficacy of a biological fungicide product, Polyversum™ (Pythium oligandrum Drechsler), in controlling grey mould of raspberries Botrytis cinerea Pers. was tested at sites around Valjevo, Požega and Šabac in 2004, 2005 and 2006. The experiments were conducted and data processed using EPPO methods. Efficacy was found to be significantly lower statistically in the experimental variants involving Polyversum™ biofungicide (E = 18.0%-53.9%) than the standard botricide Ronilan- DF (E = 56.6%-90.3%). Our results show that the biological product Polyversum™ achieved significant efficacy, although poorer than the standard fungicide Ronilan-DF. As it is a biological product almost entirely free of any toxicological and ecotoxicological limitations, it offers a significant advantage for widespread usage in plant protection.U toku 2004, 2005. i 2006. godine, na lokalitetima Valjeva, Požege i Šapca, ispitivana je efikasnost biološkog preparata PolyversumTM (Pythium oligandrum Drechsler) u suzbijanju prouzrokovača sive truleži plodova maline Botrytis cinerea Pers. Eksperimenti su izvedeni i podaci obrađeni po metodama EPPO. Utvrđeno je da je u varijantama primene biofungicida PolyversumTM efikasnost (E = 18.0%- 53.9%) statistički značajno slabija od standardnog botriticida Ronilan- DF (E = 56.6%-90.3%). Ispoljena efikasnost biološkog preparata Polyversum je značajna, iako slabija od standardnog fungicida Ronilan- DF. S obzirom da je reč o biološkom preparatu koji gotovo da nema toksikoloških i ekotoksikoloških ograničenja, to mu daje značajnu prednost za širu upotrebu u zaštiti bilja

Rubbery taproot disease (RTD) severe threat for sugar beet production in Central Europe

Rubbery taproot disease (RTD) appearance and symptoms have been described in Bulgaria, Romania and Serbia more than 60 years ago. At that time disease symptoms were associated with abiotic factors (drought). Latest researches about RTD reveal that Candidatus Phytoplasma solani is the causing agent of the disease and the presence of the disease also in Croatia, Hungary and Slovakia. After declining of the plants, roots are prone to rotting due to the activity of saprobes. Symptoms and the progress of the disease differ depending on climatic conditions. The first symptoms usually start appearing by the end of July and beginning of August. In wet years yellowing of the oldest leaves and relatively slow progress of the beet deterioration can be observed on the edges of sugar beet fields. In dry years, because of the drought, oldest leaves are being discarded very fast and the first visible symptom of the disease is a loss of turgor in young leaves during the hottest part of the day. If dry conditions continue, all leaves become necrotic, which leads to the complete decline of the plant. Taproots of diseased plants wilt, become rubbery, and stay without any rot symptoms until complete plant decline. A yield loss in the same beet field varies spatially and is usually aggregated toward the edges. Epidemiological studies of the disease are in progress

Reptalus quinquecostatus (Dufour, 1833) (Fulgoromorpha: Cixiidae) plant preferences in Serbia

Reptalus quinquecostatus (Dufour, 1833) is one of several species from the planthopper family Cixiidae that are known as vectors of plant pathogenic bacteria that can cause severe agroeconomic losses. Records of this species in Serbia by Horváth, Tanasijević and Janković refer to Oliarus quinquecostatus Dufour, 1883 [sic]. The species was described as inhabiting meadows and grasslands and reported as caught on Salix sp., Ulmus sp., Quercus sp., and Malva sylvestris. Modern-day molecular identification of species, i.e. sequencing of cytochrome oxidase subunit 1 (COI) gene, revealed the presence of R. quinquecostatus nymphs in the rhizosphere of Koeleria macrantha (Poaceae family) in eastern Serbia. This cixiid has been found in Serbia on various crops affected by ‘Candidatus Phytoplasma solani’: corn, grapevine, potato, and most recently, sugar beet. The occurrence on sugar beet was first reported in 2020 in northern Serbia when its population was aggregated on a boundary strip with several weeds: Convolvulus arvensis, Chenopodium album, Amaranthus retroflexus, Ambrosia artemisiifolia etc. During the 2021–2022 survey, the presence of R. quinquecostatus on sugar beet was confirmed on other localities in Serbia. Moreover, its populations were recorded on parsnip, tobacco and corn. Prunus spinosa and Crataegus sp. in microhabitats permeating arable land were also found preferable for R. quinquecostatus adults. Its several populations on different hosts were repeatedly sampled in June–July 2022. Populations on P. spinosa and Crataegus sp. were highly abundant and infected with ‘Ca. P. solani’, whereas in the agroecosystems, R. quinquecostatus is present in mixed population with R. panzeri, displaying minor precedence in the emergence of adults. Data on R. quinquecostatus plant preferences in Serbia support the polyphagy that has been previously reported throughout Europe. Since the genus Reptalus Emeljanov, 1971 has recently undergone nomenclatural and taxonomic revision, the use of the valid species name and proper morphological species identification, which in some cases should be supplemented with molecular tools, are crucial in biodiversity and insect pest research

Gumoza šećerne repe: dugo poznata, ali nedavno razjašnjena bolest

Pojava bolesti gumoze šećerne repe je primećena u Srbiji prvi put u Banatu i Bačkoj šezdesetih godina prošlog veka. Koren obolelih biljaka ispoljava različit stepen gumoze uz uvenuće listova. Iako je koren zaraženih repa inicijalno bez truleži, nakon uvenuća ili vađenja biljke, podložan je napadu saprofita. Simptomi gumoze repe su zabeleženi takođe u Bugarskoj i Rumuniji i primarno su dovođeni u vezu sa sušom. Narušene fizičke karakteristike korena obolele šećerne repe mogu dovesti do odbacivanja kompletnog prinosa od strane šećerana. Nakon perioda epidemijske pojave, bolest je bila sporadično prisutna. U periodu 2018-2020 godine gumoza je zabeležena u svim područjima gajenja šećerne repe u Srbiji, u epidemijskoj ili neepidemijskoj razmeri, ukazujući na periodičnu pojavu oboljenja što je karakteristično za bolesti izazvane stolbur fitoplazmom (‘Candidatus Phytoplasma solani’). Epidemijska pojava gumoze repe je u ovom periodu zabeležena i u Slovačkoj, a sporadična u Mađarskoj i Hrvatskoj. Šećerne repe sa simptomima gumoze sakupljene u navedenim zemljama su testirane na prisustvo stolbur fitoplazme primenom molekularnih metoda. Svi detektovani izolati fitoplazme su dalje genotipizirani na tri epidemiološki informativna gena tuf, stamp i vmp1. Prisustvo fitopatogene bakterije ‘Ca. Arsenophonus phytopathogenicus’, uzrokovača bolesti repe “basses richesses” (SBR) u Francuskoj, Nemačkoj i Švajcarskoj, takođe je testirano i nije utvrđeno u analiziranim uzorcima. Etiologija gumoze šećerne repe je rasvetljena u Novom Sadu (Rimskim Šančevima) gde je utvrđena asocijacija stolbur fitoplazme i tipičnih simptoma ove biljne bolesti

Field trial evaluation to RTD susceptibility/tolerance to RTD in Serbia: Is there a tolerance to RTD in current varieties?

Sugar beet is the second most important source for the sugar industry, particularly important in temperate climate zones of Central, West, and East Europe. However, its production has declined recently due to various factors of which the most important are subsidy cuts and the spread of various plant diseases. In the Pannonian Plain (Slovakia, Hungary, Romania, and Serbia), a disease called rubbery taproot disease (RTD) has been observed for along time. The variability in RTD symptoms and the extent of damage it causes have made its detection quite challenging, often leading to misdiagnoses as other diseases. However, the identification of Candidatus Phytoplasma solani as the cause of RTD has resolved the issue of its diagnosis. The latest outbreak in Serbia has had a significant economic impact on sugar beet production, prompting an urgent response to aid the industry and growers. In our study, conducted during the 2022 and 2023 seasons, we assessed the susceptibility/tolerance of thirty registered sugar beet hybrids in Serbia, evaluating their impact on root yield and quality in naturally infected experimental fields

First Report of 'Candidatus Phytoplasma solani' Infecting Parsnip in Serbia

The parsnip is a biennial plant native to Eurasia. During August and September 2016, typical phytoplasma yellows symptoms were observed on parsnip plants grown in Serbia. To our knowledge, this is the first report of phytoplasma infecting parsnip in Serbia

Phytoplasmas infecting sugar beet in central Europe

In Europe, the cultivation of sugar beet faces significant challenges due to the emergence of basses richesses syndrome (SBR) and rubbery taproot disease (RTD) which are associated with fastidious bacteria Candidatus Arsenophonus phytopathogenicus and Candidatus Phytoplasma solani, respectively. A comprehensive study conducted from 2018 to 2022 aimed to elucidate the prevalence and distribution of these pathogens in sugar beet in central Europe, focusing on the Pannonian Plain (particularly Serbia and Slovakia where RTD has been present in epidemic scales) and Germany

Rubbery taproot disease of sugar beet in Serbia associated with 'Candidatus phytoplasma solani'

Rubbery taproot disease (RTD) of sugar beet was observed in Serbia for the first time in the 1960s. The disease was already described in neighboring Bulgaria and Romania at the time but it was associated with abiotic factors. In this study on RTD of sugar beet in its main growing area of Serbia, we provide evidence of the association between 'Candidatus Phytoplasma solani' (stolbur phytoplasma) infection and the occurrence of typical RTD symptomatology. 'Ca. P. solani' was identified by PCR and the sequence analyses of 16S ribosomal RNA, tuf, secY, and stamp genes. In contrast, the causative agent of the syndrome “basses richesses” of sugar beet-namely, 'Ca. Arsenophonus phytopathogenicus'-was not detected. Sequence analysis of the stolbur strain's tuf gene confirmed a previously reported and a new, distinct tuf stolbur genotype (named 'tuf d') that is prevalent in sugar beet. The sequence signatures of the tuf gene as well as the one of stamp both correlate with the epidemiological cycle and reservoir plant host. This study provides knowledge that, for the first time, enables the differentiation of stolbur strains associated with RTD of sugar beet from closely related strains, thereby providing necessary information for further epidemiological work seeking to identify insect vectors and reservoir plant hosts. The results of this study indicate that there are differences in hybrid susceptibility. Clarifying the etiology of RTD as a long-known and economically important disease is certainly the first step toward disease management in Serbia and neighboring countries.This is the peer reviewed version of the following article: Ćurčić Ž., Stepanović J., Zübert C., Taški-Ajduković K., Kosovac A., Rekanović E., Kube M., Duduk B. Rubbery taproot disease of sugar beet in Serbia associated with 'Candidatus phytoplasma solani'. Plant Disease 2021, 105 (2), 255 – 263. [https://doi.org/10.1094/PDIS-07-20-1602-RE]