Comparison between IF and PCR for the detection of Ralstonia solanacearum
A comparison study has been carried out in France between IF (with polyclonal antibodies) and PCR for the detection of Ralstonia solanacearum (EPPO A2 quarantine pest). 701 samples of potatoes from various origins have been tested: 293 from Mediterranean countries (Egypt, Morocco, Israel, Turkey), 378 from the Netherlands, and 30 from France. Each sample consisted of 200 tubers taken from 25 tons. Details of the two testing methods are given in this paper. Only four samples from Egypt were found infected. The results showed that the levels of sensitivity of IF and PCR are comparable, as well as the costs. PCR is more specific as some cross-reaction can occur with IF. Concerning the practical aspects of both methods, PCR is less cumbersome and can be more easily automated. Per day and per person, a maximum of 24 samples can be analysed by IF, compared to 48 with PCR. In addition, once nucleic acids have been extracted for PCR, another test can be made to detect Clavibacter michiganensis subsp. sepedonicus (EPPO A2 quarantine pest). The authors concluded that both methods should be kept because they are complementary. They felt that PCR is probably easier to use routinely, as it is rapid and reliable, and that IF can be used as a complement when some difficulties are encountered.
Martin, J.; Ollivier, F.; Chaumette, E.; Hervé, A. (1997) Pourriture brune de la pomme de terre. Evaluation de la méthode de diagnostic 'PCR'.
Phytoma - La Défense des Végétaux, n° 491, 49-52.