Diseases Pests
ESCA

ESCA is caused by the basidiomycete fungi Stereum hirsutum and Phellinus igniarius, which are responsible for the degradation of the wood. Throughout the years this disease has reached all wine regions, thus becoming worrisome. ESCA can manifest itself in two ways: slowly or suddenly (also called apoplexy).
It is currently believed that ESCA is caused by the combined action of the fungi Phaeoacremonium aleophilum and Phaeoacremonium chlamydosporum, which is followed by the action of the ESCA fungi. The precursor fungi are responsible for the formation of the hard, dark necrosis that comprises the soft, light necrosis and can be transported through living material. The ESCA fungus (Fomitiporia punctata = Phellinus igniarius) causes soft, light necrosis located in the central area; it is not a parasitic fungus, since it does not develop in living wood, but the secretions it produces kill the wood.
Contamination can occur through basidiospores or mycelium of the fungi that enter through the wounds on the grapevine. The destruction of the wood involves two different stages:

- an oxidase (secreted by the fungus) acts in tannic compounds and darkens the wood, since it kills the cells
- the mycelium degrades the cellular walls destroying the wood lignin (white spongy tissue that becomes yellow and soft)

Trunk:

- White, spongy necroses. Through the longitudinal cut one can see that the spots spread throughout the entire pruned area. These spots are accompanied by black striations, which correspond to the points observed in transversal cut. The necrosed area is limited by a black line
- The transversal cut shows the centre of the branch occupied by a light brown spongy mass

Leaves:

- Slowly: necrosed marginal spots and yellowish-reddish spots between the ribs; marbled appearance; the leaves at the base of the branches are the first to be affected. 

- Apoplexy: the leaves become greyish-green from the stalk end and dry quickly. It may reach the entire vine. 

Berries:

– necrosed purplish points near or after veraison, usually only in white grape varieties.

Cultural control:

Besides avoiding major pruning cuts, one should root up the sick vines to check if the grapevines were attacked by ESCA. One of the oldest techniques to prevent the grapevines from becoming affected by ESCA is to split the trunk and keep it open with a stone to dry the wound and afterwards remove the soft part. This technique should be repeated every 2 years. 

Chemical control:

Carbendazim + flusilazole

 (NOTE: some literature suggests the use of fosetyl-aluminium, since it has shown good results in the restriction of ESCA precursor fungi. However, this active substance is not homologated for this purpose)

A animação “Comportamentos de acasalamento e postura da traça da uva, Lobesia botrana, faz parte de uma colecção intitulada “Ciclo de Vida da Traça da Uva Lobesia botrana e modo de acção de auxiliares”.

Estes materiais multimédia foram desenvolvidos sob a coordenação científica da Professora Ana Aguiar, e produzidos pela Universidade do Porto para integrarem os materiais de apoio ao processo pedagógico de disciplinas de Protecção de Culturas.

Neste momento, esta e outras animações, integram um curso on-line de formação contínua da U.Porto intitulado “Protecção Integrada da Vinha U.Porto – curso on-line”.


 
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