Identification of Eutypa lata, a grapevine parasite

Abstract

The phytopathogenic fungus Eutypa lata (Pers.: Fr.) Tul. and C. Tul., the causing agent of eutypa dieback, has been increasingly often identified in recent times as a cause of grapevine disease. It was first discovered and identified in Australian vineyards (Carter, 1973), where it represented one of the most dangerous fungus pathogens of this plant. A few years later it was discovered in European vineyards as well. This polyfagous fungus, known originally as E. armeniaca (Honsf. & Carter), was first discovered on apricot, on which it caused the "gummosis disease". In Serbia, Eutypa lata has not been determined officially. However, bearing in mind the form of its spreading (anemochory), as well as the fact that our country is a major producer of grape and fruit, we need to pay special attention to this dangerous pathogen since there are indications that it is already present in our vineyards. During the period between 2003 and 2005, an inspection of a great number of vineyards in the areas of Vršac, Fruška Gora and Kruševac, was conducted. Many of them had grapevines with typical eutypa dieback symptoms. The aim of the inspection was to find grapevines with this disease, to mark them and take samples for laboratory analysis. Marking suspicious grapevines enabled us to monitor the volume of symptoms, as well as other changes on grapevines. Different colors were used for markings, according to the principle "same color - same year" The procedure revealed that the average period between early and mild disease symptoms and extreme changes, including withering of entire vines, was 2 to 3 years. The signs of eutypa dieback on diseased grapevines are manifested: on leaves in the form of chlorosis, twisting, necrosis of the edges, drying out and falling off; on shoots, where the shortening of internodia is noticeable, as well as color change and "zig-zag" distribution of internodes; on blossoms and clusters, where absence of flowering, partial bareness and irregular berry size are observed; and on trunks, where necrosis appears on the cross section in a typical "V" form. These studies also established that there is not a single grapevine plant with symptoms indicating eutypa dieback or a similar disease that is older than 8-10 years. The research results, based on examination and monitoring of disease development in the studied vineyards in previous years, indicate that the fungus Eutypa lata, the inducer of grapevine eutyposis, is most probably present in Serbia, and that our viticulture is facing yet another serious threat. In most European and other viticultural centers, highly specialized research teams are being organized to deal with the phenomenon of eutypa dieback, and its inducer Eutypa lata, which is more and more frequently classified as a top priority disease of wooden tissue, especially considering that the economic losses are very significant and occur in all vineyards, regardless of their location. Therefore, in order to prevent infection and fight the disease successfully, we need to take immediate measures of integral protection of grapevine without any delay.

Među prouzrokovače bolesti vinove loze u novije vreme sve češće se ubraja i fitopatogena gljiva Eutypa lata (Pers.: Fr.) Tul. i C. Tul., uzročnik eutipoze. Prvi put je otkrivena i identifikovana u australijskom vinogorju (Carter, 1973), gde predstavlja jednu od najopasnijih mikoza ove biljke. Nekoliko godina kasnije otkrivena je i u vinogorjima Evrope. Ranije je ova polifagna gljiva, pošto je prvi put nađena na kajsiji, bila poznata pod imenom E. armeniaca (Honsf. & Carter), na kojoj prouzrokuje "gumoznu bolest". U Srbiji Eutypa lata još nije zvanično konstatovana. Međutim, imajući u vidu način njenog širenja (anemohorija), kao i činjenicu da je naša zemlja značajan proizvođač grožđa i voća, potrebno je obratiti naročitu pažnju na ovog opasnog patogena, jer ima indicija da je prisutan i u našim vinogorjima. U periodu 2003-2005. godine obavljen je pregled većeg broja vinograda u vršačkom, fruškogorskom i kruševačkom vinogorju. U mnogima od njih nađeni su čokoti sa tipičnim simptomima eutipoze. Cilj ovih ispitivanja bio je pronalaženje ovako obolelih čokota, njihovo obeležavanje, kao i uzimanje uzoraka za dalje laboratorijske analize. Obeležavanje sumnjivih čokota omogućilo nam je da pratimo jačinu izraženosti simptoma, kao i sve ostale promene tih čokota. Za obeležavanje su korišćene različite boje, a primenjen je princip: jedna boja - jedna godina. Ovim postupkom je ustanovljeno da od pojave početnih, blažih simptoma oboljenja, pa do pojave izuzetno izraženih promena, uključujući i izumiranje celih čokota, treba da prođe 2 do 3 godine. Znaci eutipoze na napadnutim čokotima manifestuju se na lišću u vidu hloroze, kovrdžanja, nekroze oboda, sušenja i opadanja listova, na lastarima se uočava skraćivanje internodija, promena boje, "cik-cak" raspored internodusa, na cvastima i grozdovima primetno je izostajanje cvetanja, rehuljavost i neujednačenost veličine bobica, dok se na drvetu javlja nekroza na poprečnom preseku u obliku slova V, tipičnom za ovu bolest. U ovim ispitivanjima je takođe utvrđeno da nema zasada vinove loze starijeg 8-10 godina a da se ne nađu čokoti sa ovakvim simptomima koji upućuju na eutipozu ili slično oboljenje. Rezultati istraživanja dobijeni na osnovu obavljenih pregleda i praćenja razvoja simptoma oboljenja proteklih godina u proučavanim vinogorjima, upućuju na zaključak da je gljiva Eutypa lata, prouzrokovač eutipoze vinove loze, najverovatnije prisutna u Srbiji, i da je naše vinogradarstvo suočeno sa još jednom ozbiljnom opasnošću. U većini evropskih i ostalih vinogradarskih centara organizovani su timovi visokospecijalizovanih stručnjaka koji se bave istraživanjem fenomena eutipoze i njenog prouzrokovača - Eutypa lata, jer se ona sve češće ubraja u najznačajnije bolesti drvenastog tkiva, posebno kada se uzme u obzir da su ekonomski gubici veoma značajni i da se javljaju u svim vinogradima bez obzira na njihovu lokaciju. Zbog toga, a u cilju sprečavanja zaraze, kao i uspešne borbe protiv ove bolesti, neophodno je, bez odlaganja, primeniti mere integralne zaštite vinove loze.