A survey of the scientific literature on preventative practices provided a range of disease-control efficacies (DCEs), which were calculated from multiple experimental trials on different trunk diseases (see table below). DCE is the proportion of pruning wounds which do not become infected as a result of a preventative practice. In the empirical analysis, DCEs of 25, 50, and 75% were used, which reflect the range of natural variation across study years [e.g., DCEs ranging from 29 to 88% for delayed pruning against Phaeoacremonium minimum (Larignon and Dubos, 2000)] or across pathogens [e.g., DCE of 52% for Topsin against Phaeomoniella chlamydospora vs. DCE of 80% against Lasiodiplodia sp. (Rolshausen et al., 2010)]. The high extreme of the range in DCEs is truncated at 75% to reflect that all infections may not arise through pruning wounds. For example, planting material may be infected in the nursery (Gramaje and Armengol, 2011) and, thus, it is unrealistic to assume a practice can prevent 100% of infections.
Disease control efficacies (DCEs; % pruning wounds protected) for preventative practices against three trunk diseases and six trunk pathogens. Ranges reflect data from replicated studies in the same vineyard across two years.
| Trunk disease | Preventative practices | ||
|---|---|---|---|
| Trunk pathogen | Topsin | Delayed pruning | Double pruning |
| DCE (% pruning wounds protected) | |||
| Botryosphaeria dieback | |||
| Lasiodplodia sp. | 80%a | 59 – 75%c | - |
| Neofusicoccum luteum | 60%b | - | - |
| Neofusicoccum parvum | - | 55 – 79%c | - |
| Esca | |||
| Phaeoacremonium minimum | 57%a | 29 – 88%d | - |
| Phaeomoniella chlamydospora | 52%a | 40 – 58%d | - |
| Eutypa dieback | |||
| Eutypa lata | 100%a | 90%e | 33 – 75%f |
a When applied to Chardonnay in 2005 and Zinfandel in 2006; averaged across both cultivars/years (Rolshausen et al., 2010).
b When applied to Chardonnay (Amponsah et al., 2012).
c When pruning Cabernet Sauvignon and Chardonnay in March versus December, in 2007 and 2008 (Urbez-Torres and Gubler, 2011).
d When pruning Cabernet Sauvignon in March versus January, in 1997 and 1998 (Larignon and Dubos, 2000).
e When pruning Grenache in March versus December (Petzoldt et al., 1981).
f When pruning Chardonnay and Merlot in February versus December, in 2001 and 2002 (Weber et al., 2007).
Amponsah, N.T., Jones, E., Ridgway, H.J., Jaspers, M.V., 2012. Evaluation of fungicides for the management of Botryosphaeria dieback diseases of grapevines. Pest Manag. Sci. 68, 676–683.
Gramaje, D., Armengol, J., 2011. Fungal trunk pathogens in the grapevine propagation process: Potential inoculum sources, detection, identification, and management strategies. Plant Dis. 95, 1040–1055.
Larignon, P., Dubos, B., 2000. Preliminary studies on the biology of Phaeoacremonium. Phytopathol. Medit. 39, 184–189.
Petzoldt, C.H., Moller, W.J., Sall, M.A., 1981. Eutypa dieback of grapevine: Seasonal differences in infection and duration of susceptibility of pruning wounds. Phytopathology 71, 540–543.
Rolshausen, P.E., Urbez-Torres, J.R., Rooney-Latham, S., Eskalen, A., Smith, R.J., Gubler, W.D., 2010. Evaluation of pruning wound susceptibility and protection against fungi associated with grapevine trunk diseases. Amer. J. Enol. Vitic. 61, 113–119.
Urbez-Torres, J.R., Gubler, W.D., 2011. Susceptibility of grapevine pruning wounds to infection by Lasiodiplodia theobromae and Neofusicoccum parvum. Plant Pathol. 60, 261–270.
Weber, E.A., Trouillas, F.P., Gubler, W.D., 2007. Double pruning of grapevines: a cultural practice to reduce infections by Eutypa lata. Amer. J. Enol. Vitic. 58, 61–66.