The effect of fertiliser on detection of Apple stem grooving virus and Tobacco ringspot virus by herbaceous bioassay

Herbaceous indicator bioassays are used to screen for unwanted plant viruses on imported plant material To optimise virus detection the effect of plant nutrition was investigated to determine whether this plays a role in virus symptom expression and severity Apple stem grooving virus and Tobacco ringspot virus were inoculated onto a range of herbaceous indicator species grown in potting mix supplemented with differing rates of slowrelease fertiliser Higher rates of fertiliser resulted in better plant nutrition and a greater incidence of virus expression and more severe expression of disease in the seven indicator plant species Overall disease assessments indicated that plant nutrition affects plant growth virus infection rate and virus symptom expression As virus infection affects plant growth and leaf colour good plant nutrition is important to avoid masking virus symptoms and to optimise the detection of viruses in postentry quarantine facilities