Comparison of viral infection risk between organic and conventional crops 1 of tomato in Spain

Abstract

The harmful effects of conventional agriculture on the environment and human health have been an increasing concern, resulting in the search for alternative and more sustainable agricultural systems in the last decades. Organic farming is the fastest growing system worldwide, but there is a controversial debate on the ability of the agroecological practices to cope with diseases and pests and produce food for the world population. However, comparative studies on the effect of organic farming on plant disease are almost non-existent particularly concerning plant virus diseases. In this work, a survey of Tomato mosaic virus (ToMV), Cucumber mosaic virus (CMV) and Tomato spotted wilt virus (TSWV) was performed in tomato crops under organic or conventional management by sampling 40 small farms in Eastern Spain. ToMV had the highest incidence whereas few plants were infected by CMV and none by TSWV. Viral infection risk was estimated as the probability of a plant being infected by at least one of the three viruses or by each virus separately according to a Bayesian logistic regression model. Our analysis showed that the infection risk by these viruses was lower in organic than in conventional farms in two non-consecutive years.