Fusarium Dry Rot in Garlic: Hidden Infection of Planting Material Leading to High Infestation Rates During Storage of the Resulting Harvest

Abstract Fusarium dry rot is a post-harvest disease of garlic that is becoming increasingly important worldwide. This fungal disease can be transmitted through planting material, however, the significance of this transmission route on the harvested crop remains unclear. Therefore, this study aimed to analyse the infection rate of commercially available planting material and the resulting infection rate of stored garlic. The methodology comprised a visual examination, isolation and molecular identification of the pathogen from peeled cloves of the planting material and the subsequently harvested and stored garlic produced in two farms. The storage conditions encompassed non-temperature-controlled storage and refrigerated storage at −2 °C in both instances. The results demonstrated that all bulbs of the planting material and the stored garlic exhibited symptoms of Fusarium dry rot. Fusarium proliferatum and F. oxysporum were the predominant species in both the garlic planting material and the stored garlic. The disease incidence for Fusarium dry rot was found to be 100%, and the isolation rate for Fusarium spp. was 98%, which are higher than the previously documented values. Despite these high infection rates, the disease remained hidden underneath the garlic skin. Furthermore, mechanical damage was observed on cloves along with Fusarium dry rot symptoms covered by intact skins. However, the significance of mechanical damage caused by harvesting and post-harvest handling remained uncertain. Further studies are needed to elucidate these dynamics and develop strategies for managing the consequences of Fusarium -infested planting material when Fusarium- free material is not available.