Table C.1: Lag period

Overview of the results of the Expert Knowledge Elicitation (1st EKE question)
Parameter	Duration of the lag period
Stratification	Grapevine production areas in the EU with average yearly temperature above 17°C as average of the coming 30 years
Question	How long is the average duration of the lag period, i.e. the time from the first infectious plant(s) present in a vineyard to the expression of symptoms in enough plants to allow spread between vineyards by natural means, e.g. by rain, wind? [months]
Results	P1%	P2.5%	P5%	P10%	P16.7%	P25%	P33.3%	P50%	P66.7%	P75%	P83.3%	P90%	P95%	P97.5%	P99%
Elicited values	3					19		35		47					60
EKE results	2.99	4.31	6.29	9.90	14.3	19.6	24.6	34.1	43.2	47.6	52.0	55.4	58.0	59.2	60.0
Fitted distribution	BetaGeneral (1.1563,1.0001,1.9,60.5)
Figure (C.1a): Comparison of elicited and fitted values/density function to describe the remaining uncertainties of the parameter							Figure (C.1b): Cumulative distribution function (CDF) of the likelihood of the parameter

Summary of the evidence used for the evaluation
The experts considered several factors influencing the presence and the length of a lag phase, in particular Literature on the incubation time of Xcv, esp. Naue et al. (2014) and Zucal et al. (2016). Production seasons, esp. the length of the winter dormancy period, in the EU. The probability of bacterial transmission via pruning, e.g. manual and mechanic. Agricultural practices in the EU, esp. pruning, mechanisation, treatments (esp. with copper), rain/hail protection. Product profile of vineyards in the area under consideration, i.e. the EU area with average yearly temperature above 17°C as average of the coming 30 years.
Main uncertainties
Unknown susceptibility of EU cultivars, esp. with/without seeds. Pest development of Xcv under EU climatic conditions, e.g. efficacy of the inocula, number of infection cycles per year. Expression of symptoms / duration of a latent phase under EU climatic conditions. The role of viticultural practices for local spread, e.g. mechanisation.
Reasoning for a scenario which would lead to a reasonable high duration	The judgement on the upper limit considers that Spread within a vineyard is triggered by natural means compared to human activities, e.g. pruning, machinery. Natural events, e.g. hail, thunderstorms, are less frequent. High proportion of vineyards, esp. table grapes, are protected. Regular treatments with copper are effective against evaded Xcv.
Reasoning for a scenario which would lead to a reasonable low duration	The judgement on the lower limit considers that Large number of infected plants are introduced in the vineyard. During the vegetation period Xcv will quickly develop and spread within the vineyard due to its polycyclic nature. High degree of mechanisation for pruning and harvest. Prolonged vegetation period of the production system.
Fair estimate as judgement on the weighted evidence	The judgement on the median considers that EU climatic conditions are less favourable for pest development than in the tropical countries of origin, e.g. Brazil, India. EU viticultural practices include several measures delaying the development/spread of Xcv.
Precision of the judgement as description of remaining uncertainties	The judgement on the interquartile range considers that High uncertainties on lower values due to possible high infectivity and unknown starting conditions. High uncertainties on higher values due to unknown effect of EU climatic conditions and viticultural practices.