Diagnostic samples are defined as ad hoc samples not categorised as official and/or certification samples. These samples normally consist of a few tubers/plants/pods/seeds/stalks/stems with or without disease symptoms. A unique benefit which Plantovita offers is that the Technicians become specialists in respect of the diagnosis of potato and dry bean diseases on account of their focussing on these crops.
Diagnostic samples must be accompanied by a Sample Investigation Form. If an official of Potato Certification Service or a SANSOR inspector submits a diagnostic sample, the official/inspector must complete the documentation. A sample number will be allocated, which will serve as reference in all communications in connection with the sample. Good practice is when a client identifies a submitted sample through his/her own unique number or description of the sample. This allows the laboratory and the client to match results and samples.
Diagnostic samples may also be submitted by private clients (producers and private companies). Private clients are requested to provide sufficient information for the completion of the Sample Investigation Form by the person who submits the sample or the Technician who receives and handles the sample. The laboratory allocates a unique number to the sample. This number serves as reference number in all communication with the client in connection with the sample.
Only one sample is handled at a time in order to limit the risk of contamination between samples. The sample is investigated properly for typical disease symptoms, for example wilt, necrosis, discolouration, rotting, mould (fungal growth) and any lesions or slime and moisture secretions typical of some pathogens.
As soon as the Technician can by means of this investigation ascertain which disease is involved, the sample is referred to a specific or even to more than one disease laboratory of Plantovita where it is tested in terms of the relevant protocols.
The techniques used at present entail conventional (biochemical) tests, serological tests (the ELISA test) and molecular tests (PCR).
Diagnostic samples are handled with the same care as official and other private samples. Attention is paid to a diagnostic sample until an answer can be provided to the client. If Plantovita does not have the necessary testing material or methodology at its disposal for the confirmation of a suspected diagnosis, the sample may, with the permission of the client, be sent to a university or the Department of Agriculture. This is communicated to the client and only done with his/her permission.
The results of the diagnostic investigation are conveyed to the client on the Sample Investigation Form.
To date the Diagnostic Section has identified the following pathogens and physiological deviations: