Monitoring soil fungus disease

The EU dominates the world's olive sector, both in production and consumption. Yet, the small businesses involved suffer from low profit margins, and are vulnerable to international competition and drops in productivity.

Verticillium dahliae (VD), a soil-borne pathogen, is the greatest threat to productivity. The disease affects yield in many crop species, including olives, and in recent years outbreaks have been occurring with increasing frequency.

Conventional methods of detection are complex and slow, plus require trained technicians. Thus, the EU has funded the project 'Inexpensive and reliable on-site solution for olive oil producers to contain Verticillium wilt' (VERTIGEEN). The goal is to develop a rapid, on-site system for VD detection, combining DNA amplification and electrochemical methods. The resulting device is affordable, easy to use and quick.

Progress to date is on track. The study team initially surveyed the European market's requirements for detection. The questionnaire-based information obtained from small and medium-sized enterprises in four countries helped tailor the device to the sector's needs. The information will also determine the business plan to be completed during the project's second half.

Protocols for sample collection and processing have been defined for soil and plant samples. Other processing methods were also compared, and the effects of seasonality have been studied. Initial primers for DNA amplification have been designed, yet further optimisation work will be needed.

The team prepared designs for hardware components, including a polymer reaction tube and screen-printed electrodes. Electrical diagrams for the detection unit have also been prepared, and the housing box has been designed and constructed. A user interface involving a seven-inch touchscreen is under development.

Substantial project efforts went into literature searches concerning how soil inocula levels affect disease incidence, disease risk and incidence factors. The information will yield a disease risk category system.

The VERTIGEEN project will yield a system allowing olive growers to quickly and simply test soil and plant samples for VD. The information will allow growers to minimise infection risks and outbreaks, and thus maximise yield and competitiveness.