Massimo Galli

Liberomyces pistaciae sp. nov., the causal agent of pistachio cankers and decline in Italy

Abstract A new canker and decline disease of pistachio (Pistaciavera) is described from Sicily (Italy). Observations of the disease and sampling of the causal agent started in spring 2010, in the area where this crop is typically cultivated, Bronte and Adrano (Catania province) and later extended to the Agrigento and Caltanissetta provinces. Isolations from the margins of twig, branch and stem cankers of declining plants resulted in fungal colonies with the same morphology. Pathogenicity tests on 5-year-old potted plants of Pistaciavera grafted on P.terebinthus reproduced similar symptoms to those observed in nature and the pathogen was confirmed to be a coloniser of woody plant tissue. Comparison of our isolates with the type of the apparently similar Asteromellapistaciarum showed that our isolates are morphologically and ecologically different from A.pistaciarum, the latter being a typical member of Mycosphaerellaceae. Asteromellapistaciarum is lectotypified, described and illustrated and it is considered to represent a spermatial morph of Septoriapistaciarum. Multi-locus phylogenies based on two (ITS and LSU rDNA) and three (ITS, rpb2 and tub2) genomic loci revealed isolates of the canker pathogen to represent a new species of Liberomyces within the Delonicicolaceae (Xylariales), which is here described as Liberomycespistaciaesp. nov. (Delonicicolaceae, Xylariales). The presence of this fungus in asymptomatic plants with apparently healthy woody tissues indicates that it also has a latent growth phase. This study improves the understanding of pistachio decline, but further studies are needed for planning effective disease management strategies and ensuring that the pathogen is not introduced into new areas with apparently healthy, but infected plants.

Teratosphaeria stem canker disease on Eucalypt in Italy

The disease originally named as Coniothyrium canker was observed in Italy for the first time in late summer 2015. The outbreak involved several trees of a hybrid clone of E. camaldulensis × E. viminalis, and few E. camaldulensis trees, while the parental species E. viminalis as well as other eucalypts species, including E. grandis, did not show any symptoms. The pathogen was identified as Teratosphaeria gauchensis on the basis of morphological and molecular evidences, and Koch’s postulates were fulfilled. Bayesian phylogenetic analysis of the sole T. gauchensis strains based on four concatenated genes (ITS, β-Tub, TEF-1α, and ATP6) grouped all the Italian isolates together with those from Hawaii, Ethiopia in one paraphyletic group, which included a South-American subclade. A further Bayesian analysis based on two genes (ITS and TEF-1α) which included 81 sequences of closely related species besides T. gauchensis namely, T. stellenboschiana and T. zuluensis, showed a certain level of variability within T. gauchensis clade in which T. stellenboschiana was nested. South-American strains confirmed to be high variable in both analysis. The outbreak of Teratosphaeria stem canker in Italy appears to be as a result of a recent introduction, from several independent introductions. This is consistent with the fact that the Italian isolates do not form a single monophyletic group but are interspersed by other geographical isolates.

Phytophthora σε Juglans spp. (καρυδιες)

Το γένος Juglans αποτeλeίται από πeρίπου 21 eίδη που απαντώνται στη Βόρeια και Νότια Αμeρική, την Eυρώπη και την Ασία (http://www.discoverlife.org). Πέντe eίναι τα κύρια eίδη που μπορούν να θeωρηθούν ως αντιπροσωπeυτικά των τριών βασικών ηπeίρων, τα eίδη J. hindsii και J. nigra eίναι από τη Βόρeια Αμeρική και πeριλαμβάνονται στην ομάδα της ≪μαύρης καρυδιάς≫, τα eίδη J. mandshurica και J. sieboldiana eίναι από την Ασία και πeριλαμβάνονται στην ομάδα των ασιατικών ≪butter nuts≫, eνώ το eίδος J. regia , που eίναι γνωστή ως κοινή καρυδιά ή αγγλική (πeρσική) καρυδιά, μπορeί να συμπeριληφθeί στα eυρωασιατικά eίδη. Το eίδος Juglans regia eίναι το πλέον κοινό eίδος καρυδιάς που καλλιeργeίται eυρέως σe όλο τον κόσμο, για τούς καρπούς του ή την παραγωγή ξυλeίας. Η φυσική eξάπλωση της πeρσικής (αγγλικής) καρυδιάς eπeκτeίνeται από την Ασία μέχρι την ανατολική Eυρώπη, όπως τα Βαλκάνια και τα Καρπάθια. Πάνω από το 10% του παραγωγικού δυναμικού της καρυδιάς, σe eτήσια βάση διeθνώς, χάνeται λόγω προσβολών από έντομα και ασθένeιeς. Για πολλές από τις σοβαρές ασθένeιeς, η χημική αντιμeτώπιση eίναι eίτe ανύπαρκτη ή αναποτeλeσματική. Οι προσβολές Phytophthora στο ριζικό σύστημα και το λαιμό των δένδρων θeωρούνται ότι αποτeλούν μια βασική αιτία απωλeιών σe πeριοχές μe eκτeταμένη καλλιέργeια καρυδιάς στην Eυρώπη και την Αμeρική. Η συχνότητα eμφάνισης και η έκταση σηψιρριζιών σχeτίζeται άμeσα μe την υγρασία στο έδαφος. Για ορισμένα eίδη Phytophthora και συγκeκριμένα υποκeίμeνα eμβολιασμού (π.χ. J. regia ), ο παρατeταμένος κορeσμός του eδάφους μe υγρασία αυξάνeι σe μeγάλο βαθμό την ένταση της προσβολής.

Phytophthora na Juglans spp. (vlašsky orech)

Rod Juglans zahrnuje asi 21 druhů vyskytujicich se v Severni a Jižni Americe, Evropě a v Asii (http://www.discoverlife.org). Pět hlavnich druhů lze považovat za zastupce třech hlavnich kontinentalnich skupin - J. hindsii a J. nigra ze Severni Ameriky jsou řazeny do skupiny tzv. Ořesaků cerných, J. mandshurica a J. sieboldiana z Asie jsou řazeny do skupiny ořesaků popelavých, zatimco J. regia, znamý jako ořesak kralovský resp. vlasský nebo tež anglický (perský) ořesak, může být zahrnut do skupiny Euroasijských druhů. J. regia j e celosvětově nejvice rozsiřený a pěstovaný druh, ať už pro produkci plodů nebo dřeva. Za původ ořesaku kralovskeho lze považovat oblast od Asie po východni Evropu – oblast Karpat a Balkanu. Vice než 10% potencialni rocni produkce vlasských ořechů je ztraceno kvůli chorobam a skůdcům. Pro mnoha onemocněni je chemicka ochrana buď nedostupna nebo neucinna. Hniloby kořenů a kořenoveho krcku jsou považovany za původce zvysujicich se ztrat v hlavnich pěstitelských oblastech v Evropě i Americe. Výskyt a važnost hnilob kořenoveho krcku a kořenů jsou uzce vazany na půdni vlhkost. Pro druhy rodu Phytophthora a některe druhy podnoži stupeň nasyceni půdy vodou a delka vlhkeho obdobi dramaticky ovlivňuji chorobu, jejiž važnost stoupa s delkou vlhkeho obdobi.

Phytophthora na orehih Juglans spp.

Rod Juglans obsega okoli 21 vrst, ki so razsirjene v Severni in Južni Ameriki, Evropi in Aziji (http://www.discoverlife.org). Pet vrst zastopa tri glavne skupine orehov: J. hindsii in J. nigra, ki izvirata iz Severne Amerike, sta predstavnika crnih orehov, J. mandshurica in J. sieboldiana izvirata iz Azije in zastopata t. i. ‘Asian butternuts’, J. regia, navadni ali evropski (perzijski) oreh pa se uvrsca v azijsko-evropsko skupino. J. regia je v svetovnem merilu najbolj razsirjena vrsta orehov. Gojijo ga predvsem kot sadno drevo, cenjen pa je tudi orehov les. Obmocje naravne razsirjenosti navadnega oreha se razteza od Azije do predelov vzhodne Evrope (Balkan in Karpati). Zaradi skodljivcev in bolezni propade letno prek 10% pridelka orehov. Za zatiranje skodljivih organizmov marsikdaj nimamo primernih kemicnih sredstev ali pa so premalo ucinkovita. V vseh vecjih pridelovalnih obmocjih orehov v Evropi in Ameriki nastajajo zaradi trohnobe korenin in koreninskega vratu, ki ju povzrocajo patogeni iz rodu Phytophthora, vse vecje izgube. Pojav in jakost bolezni sta tesno povezana s talno vlago. Pri nekaterih podlagah (npr. J. regia ) ima trajanje zasicenosti tal z vodo velik vpliv na trohnobo korenin in koreninskega vratu, saj obseg in jakost bolezni izrazito narascata s trajanjem zasicenosti tal z vodo.

Phytophthora em Juglans spp. (nogueiras)

O genero Juglans inclui 21 especies que se distribuem ao longo do Norte e Sul da America, Europa e Asia (http://www.discoverlife.org). Existem cinco especies principais que podem ser consideradas como representativas dos tres principais blocos continentais como, J. hindsii e J. nigra* que sao da America do Norte e estao incluidas no grupo das nogueiras negras, J. mandshurica e J. sieboldiana que sao oriundas da Asia e estao incluidas nas “butternuts” asiaticas, enquanto J. regia* tambem denominada como nogueira inglesa, persa ou comum, e o membro do genero Juglans com maior importância a nivel economico, sendo cultivada em regioes temperadas nao so pela qualidade da madeira mas tambem pelos frutos que produz, incluindo-se no grupo das especies Asiatico-Europeias. A nogueira persa e originaria de uma regiao localizada entre as montanhas da Asia Central tendo-se estendido para a zona Este da Europa, como Peninsula dos Balcas e Carpatos. Anualmente, mais de 10% do potencial de producao de nozes e perdido atraves dos prejuizos causados por pragas e doencas. Na maior parte das doencas o controlo com recurso a quimicos encontra-se indisponivel ou e ineficaz. A podridao radicular e da copa causada por Phytophthora pode ser considerada como uma importante forma de destruicao das maiores areas de producao de nogueiras na Europa e na America. A incidencia e a severidade da podridao do sistema radicular e do colo causada por Phytophthora estao diretamente relacionadas com a humidade do solo. Para algumas especies de Phytophthora e para alguns porta-enxertos (i.e. J. regia ) o encharcamento do solo afeta dramaticamente a doenca cuja severidade aumenta com o aumento do periodo de duracao do encharcamento. * Cultivadas em Portugal

Phytophthora sur Juglans spp. (noyer)

Le genre Juglans comprend environ 21 especes presentes en Amerique du Nord et du Sud, en Europe et en Asie (http://www.discoverlife.org). Les cinq principales especes de ces trois continents sont J. hindsii et J. nigra, originaire d’Amerique du Nord et appartenant au groupe des noyers noirs, J. mandshurica et J. sieboldiana , originaire d’Asie, et enfin J. regia , le noyer commun, qui fait partie des especes eurasiatique. J. regia est l’espece cultivee la plus repandue dans le monde, a la fois pour la production de fruits et de bois. Son aire d’origine s’etend de l’Asie a l’Est de l’Europe, jusqu’aux Balkans et aux Carpates. Chaque annee, les maladies et insectes provoquent la perte de plus de 10% de la production. La lutte chimique contre les principales maladies est soit inexistante soit inefficace. Les necroses sur racines et collet causees par Phytophthora spp . sont responsables de pertes de plus en plus importantes dans les parcelles de noyer en Europe et en Amerique. L’incidence et la severite de cette maladie est fortement correlee a la teneur en eau du sol. Pour certains Phytophthora spp. et porte-greffes ( J. regia ), plus la duree de saturation en eau du sol est longue, plus la severite de la maladie augmente.

Juglans spp. (cevizler) de Phytophthora

Juglans cinsi Kuzey ve Guney Amerika, Avrupa ve Asya’ da bulunan yaklasik 21 turden olusmaktadir (http://www.discoverlife.org). Bes ana tur, uc ana kita blogunun temsilcileri olarak kabul edilmektedir cunku J. hindsii ve J. nigra Kuzey Amerika kokenlidir ve onlar siyah ceviz grubuna mensupturlar, J. mandshurica ve J. sieboldiana Asya beyaz cevizi olarak bilinirken J. regia yaygin ceviz veya Ingiliz (Iran) cevizi Asya-Avrupa turu grubuna girmektedir. Juglans regia hem meyvesi hem de kerestesi icin dunyada en yaygin yetistirilen turdur. Iran (Ingiliz) cevizinin orijininin Asya’ dan Balkan ve Karpatlar gibi dogu Avrupa’ ya kadar uzandigi rapor edilmektedir. Hastalik ve zararlilardan dolayi yillik %10’ un uzerinde bir potansiyel ceviz kaybi olmaktadir. Ana hastaliklarin cogu icin kimyasal mucadele sekli ya yoktur ya da etkisizdir. Phytophthora kok ve kok bogazi curuklugu, Amerika’ da oldugu kadar Avrupa’ da da artan bir kayip kaynagi olarak kabul edilmektedir. Phytophthora kok, kok bogazi curuklugu cikisi ve siddeti toprak rutubeti ile yakin iliskilidir. Bazi Phytophthora spp. ve bazi anaclar (or. J. regia ) icin toprak doymuslugunun suresi hastaligi belirgin olarak etkiler yani siddet doygunluk suresi ile birlikte artmaktadir.