Improvement of a diagnostic test to allow more precise localisation of Tobacco Rattle Virus in fields

A sensitive PCR-based method was used to map the occurrence of virus in the roots of weeds in fields prior to potato cropping (2004). Spraing susceptible potatoes were then used to assess the predictive ability of the test (2005). 

TRV was successfully identified in weeds at the sites studied. Risk areas, where high levels of virus were detected in 2004, were correlated with high levels of spraing in 2005. However, in areas with low levels of virus infection there was a weaker relationship between the test results and the levels of spraing that developed in 2005. It was concluded that the assay offered benefits compared to some methods available at the time. However, in areas with low level virus infection environmental factors that influence nematode feeding/virus transmission may have a disproportionate influence on the occurrence of spraing.