Bioimpedance Parameter as a Risk Factor to Assess Pine Decay - An Innovative Approach to the Diagnosis of Plant Diseases

Abstract

Electrical impedance spectroscopy, EIS, has been proving efficacy and utility in a wide range of areas, from the characterization of biological tissues to living organisms. Several commercial solutions, with high precision and resolution, are available. Nonetheless, the typical equipments are expensive, unfeasible for in vivo and in field applications and unspecific for concrete applications. These features, together with the lately demands in the vegetal field, fundament this work. Actually, the fast spread of asymptomatic forest diseases, with no cure available to date, such as the pinewood disease, PWD, constitute a problem of economical and forestall huge proportions. Herein is proposed a portable EIS system, for biological applications, able to perform AC current or voltage scans within a selectable frequency range. The procedure and the results obtained for a population of 24 young pine trees (Pinus pinaster Aiton) are also presented. Pine trees were kept in a controlled environment and were inoculated with the nematode (Bursaphelenchus xylophilus Nickle), that causes the PWD, and also with bark beetles (Tomicus destruens Wollaston). Some degree of discrimination between different physiological states was achieved. These results may constitute a first innovative approach to the diagnosis of such types of diseases.