Table 1.

Variables used in the study.

Variable	Definition
ISi= Number of infected plants/ Number of singly inoculated plants	Infection rate after single inoculation
ITot= (Number of singly infected plants + Number of co-infected plants) / Number of simultaneously inoculated plants	Total infection rate of a virus
ITh= ISi(BYDV-PAV) x ISi(WDV)	Theorical co-infection rate according to Lacroix et al.(2014)
ISim= Number of co-infected plants/ Number of co-inoculated plants	Co-infection rate after simultaneous inoculation
ISeq= Number of co-infected plants/ Number of pre-infected plants submitted to second inoculation step	Co-infection rate after sequential inoculation
TSi= Number of infected plants/ Number of plants inoculated from singly-infected source plant	Transmission rate from singly-infected plants
TCi= Number of infected plants/ Number of plants inoculated from co-infected source plant	Transmission rate from co-infected plants