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advid excoriose control strategies in integrated protection associação para o desenvolvimento da vi cultura duriense introduction excoriose is a disease caused by two different fungi phomopsis viticola and macrophoma flaccid the european form of excoriose also known in portugal as desnoca caused by macrophoma flaccida is better known than the american form caused by phomopsis viticola its incidence has become significant in some varieties and regions particularly in years of high rainfall at the time of budbreak which is a factor of development of the disease together with lack of care in the selection of scions and the replacement of powdered sulphur by other products damage excoriose is responsible for a reduction in production mainly due to the breakage of canes and vine shoots desnoca and consequent difficulties in pruning in subsequent years as well as the elimination of wood tissue in canes and branches leading to their progressive death although rarely it may also affect inflorescences or small clusters and berries resulting in their destruction close to ripening symptomatology in the spring the fungus may settle on all the herbaceous parts of the grapevine in general the more visible symptoms are small more or less deep round or linear black spots on the internodes at the base of the vine shoots photo 1 and this symptomatology may also appear on the petioles and main veins of leaves and on cluster stalks the leaves present small spots black with a yellow halo which may be mistaken for symptoms of mite damage photo 3 in the summer the vine shoot lesions develop to form brownish necroses with spindleshaped stripes with clearly marked dark surphoto 2 symptom of excoriose on the cane source srpv reims photo 4 excoriose on a cane in the winter photo 1 symptom of excoriose on the base of vine shoots information bulletin 05-10 · douro region wine cluster april 2010 photo 3 excoriose on leaves diseases and pests 1994 face scabs and extensive lesions with perpendicular stripes with a cork-like appearance resembling bars of chocolate photo 2 the grape berries may also be attacked presenting light and then dark brown areas with spots frutifications that eventually dry out the appearance of these symptoms being very rare in the region in the autumn the bark in the affected areas whitens photo 4 and the black spots pycnidia that subsequently appear develop in the winter to ensure infections in the following spring biology the fungus is preserved during the winter in the form of mycelium and pycnidia on canes and also on trunks and branches in high humidity conditions the pycnidia exude white gelatinous tendrils of spores that may penetrate herbaceous parts fig 1 germination of the spores does not require the presence of water relative humidity above 95 being sufficient their dissemination occurs over short distances through wind and rain the disease thus remaining quite localised around the infection the dissemination of excoriose over greater distances requires the transport of infected plant material and infected pruning waste infections only occur in the phenological stages d and e first leaf unfolded up to 2-3 leaves unfolded with favourable temperatures 8-10 ºc and rain for at least 12 hours · the touriga nacional and tinta barroca varieties among other have shown greater sensitivity to the disease and should be more closely monitored for symptoms advid · quinta de santa maria · apartado137 · 5050-106 godim peso da régua · tel +351 254 312940 · fax +351 254 321350 · e-mail advid@advid.pt · www.advid.pt

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fig 1 biological cycle of excoriose control strategies risk estimate the risk estimate uses sampling based on visual observation of secondary symptoms of the disease at the time of pruning splitting and excoriation on canes black spots this observation must cover the first four internodes of each vine shoot to determine the intensity of the attack by the disease and its distribution on the grapevine means of control cultural control identify affected vine stocks in the summer and mark them for future intervention in the winter use healthy or disinfected grafting scions cut affected arms down to healthy tissue this infected material should not be left on the ground but instead burned along with dead vines which should be grubbed up and burned avoid large pruning wounds and disinfect pruning tools whenever they are used on affected vines chemical control treatments against excoriose should be carried out at the post-budbreak stage in order to ensure protection of new parts against contamination by the mycelium in integrated protection post-budbreak treatments should be carried out with the active substances referred to in table 1 as strategies to be adopted the following treatment schemes can be implemented two treatments one with 30 to 40 of shoots at stage d first leaf unfolded and the second treatment with 40 at stage e 2 to 3 leaves unfolded with contact and penetrant products or a single treatment at stage d with phosethyl-al associated with a contact product folpet or mancozeb these associations ensure with a single treatment at stage d the same protection as other fungicides applied twice the systemic effect of phosethyl-al provides sufficient protection during the shoots period of maximum receptivity table 1 active substances approved for integrated protection to control excoriose active substance contact products sulphur folpet mancozeb metiram propineb cpi a a a2 a2 a2 penetrant products azoxystrobin azoxystrobin+folpet metiram+pyraclostrobin a2 a2 a2 systemic products folpet+aluminium phosethyl aluminium phosethyl+mancozeb a2 a2 caption cpi criteria for use in integrated protection a active substance recommended in ip a2 active substance recommended in ip for no more than two applications for further information on plant protection products to be used against excoriose please refer to the advid list of fungicides approved in integrated protection 2009 publishing details coordina on fernando alves texts fernanda almeida produc on and prin ng advid april 2010 print run 250 copies advid · quinta de santa maria · apartado137 · 5050-106 godim peso da régua · tel +351 254 312940 · fax +351 254 321350 · e-mail advid@advid.pt · www.advid.pt

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