Assessment of Commercial Fungicides against Onion (Allium cepa) Basal Rot Disease Caused by Fusarium oxysporum f. sp. cepae and Fusarium acutatum.

Ofir Degani,Ben Kalman

doi:10.3390/jof7030235

Ofir Degani, Ben Kalman

Open Access

https://doi.org/10.3390/jof7030235

Copy DOI

Abstract

The onion basal rot disease is a worldwide threat caused by species of the genus Fusarium. Today, Israel’s control of this disease is limited to a four-year growth cycle and Metam sodium soil disinfection. Here, commercial chemical fungicides were evaluated as control treatments against two of the primary pathogens involved, F. oxysporum f. sp. cepae and F. Acutatum. Out of 10 fungicides tested on culture plates, 3, Prochloraz, Azoxystrobin + Tebuconazole, and Fludioxonil + Sedaxen, had strong inhibitory effects on mycelial growth and were selected and tested in seeds in vitro. The preparations were applied as a seed coating and tested in two commercial cultivars, Riverside (Orlando, white cv.) and Noam (red cv.). Prochloraz (0.3% w/w concentration), the most promising compound, was efficient in reducing the Noam cv. sprouts’ disease symptoms. This preparation had no harmful in situ-toxicity effect and did not influence the plants’ seed germination and early development. In Noam cv. potted 30-day-old sprouts, the Prochloraz treatment was able to reduce the harmful impact of F. oxysporum f. sp. cepae. on the seedlings’ wet biomass, but was not effective in the Riverside cv. or against the F. acutatum pathogen. This suggests that future protective strategies must include an effective protective suit tailored to each of the pathogen species involved and the onion cultivar. The methods presented in this work can be applied for rapidly scanning multiple compounds while gradually ruling out ineffective ones. Eventually, this screening will enable field testing of the highest potential fungicides that successfully pass the pot experiments.

Highlights

Onion Allium cepa L. is a member of the Amaryllidaceae family known as the common onion or bulb onion
Tebuconazole alone (Orius 25) or in mixture with Azoxystrobin (Azimut), Prochloraz (Sportak), and Fludioxonil + Sedaxen (Vibrance), revealed significant pesticide potential in inhibiting the pathogen F. acutatum series of experiments that would gradually increase the investment in time and work without wasting effort if the treatment had not successfully passed the early steps
Reports have accumulated from farmers about an increase in cases and the spread of Fusarium onion basal rot disease (FBR) in fields in Israel

Summary

Introduction

Onion Allium cepa L. is a member of the Amaryllidaceae family known as the common onion or bulb onion. Onion is an important vegetable crop globally and accounts for 23.8%. Of the world’s total vegetable production area (FAOSTAT, 2019 Food and Agriculture Commodity Production data). In Turkey, the world’s largest onion producer, onion Fusarium basal rot disease (FBR) is considered a significant threat to this cultivar. In Amasya, a prominent Turkish onion production region, more than 80% of onion fields are infected [1]. In India, which ranks second in global onion production, FBR is one of the most devastating onion diseases, and yield losses in the field and post-harvest storage can reach 50% [2]. In Israel, the cultivation area of dry onions was 4,024 hectares in 2019

Methods

Results

Discussion

Conclusion