The etiology cluster of the PROPHYLE platform offers solutions to emerging or poorly explained diseases encountered mainly by professionals of agricultural sectors. PROPHYLE implements a rational diagnostic approach from the field to the laboratory in order to distinguish problems of biotic origin from abiotic disorders by symptom observations, taking into account the farming context, laboratory investigations and using bibliographical resources.

Diagnostic and etiology of crop diseases

In response to expertise requests, the etiology cluster offers a "first-line" diagnosis (following the submission of photographs and/or samples) that can lead either to services or research projects. A wide range of tools is available:

• Visual observation (light and electron microscopy)
• Inoculation of test plants
• Microbiological isolation
• Serological analyses (ELISA, strip tests)
• Molecular analyses (PCR, sequencing…)

Figure: Etiology of vascular disease of eggplant
- canker on stems, with formation of cream to pinkish cottony pads (sporodochia) producing numerous spores (top, left),
- development of Fusarium oxysporum f. sp. melongenae strains after microbiological isolation from symptomatic vessels (top, right),
- observation of Fusarium oxysporum f. sp. melongenae spores using an optical microscope (bottom, left),
- reproduction of symptoms after inoculation on young eggplant plants (bottom, right).

Biological material ressources

As part of its research, the Plant Pathology unit develops and manages in-house collections of plant pathogens in its areas of expertise: bacteria, fungi and viruses.The etiology cluster offers:

• Isolation and collection of pathogens
• Provision of isolates of pathogens, as well as insect vectors (whitefly, aphid) and positive controls (e.g. DNA or RNA extracts)
• Fungal and bacterial inoculum production.

Resources for diagnostic

The etiology cluster also offers:

• Diagnostic training courses, which may include classroom theory sessions and practical sessions involving observation in the field and examination of samples in the laboratory.
• Free access to diagnostic resources via the ephytia applications, also available on the web and downloaded from the Apple & Play Store mobile platforms. You can access:
  • to several plant health applications, in particular to identify diseases and pests by proposing a multi-criteria diagnosis, to understand their biology and to choose appropriate protection methods
• to Di@gnoview: a free remote diagnosis service that allows sending digital photos and receiving expert advice by e-mail.