Application of Bioactive Coatings Based on Chitosan and Propolis for Pinus spp. Protection against Fusarium circinatum

Iosody Silva-Castro,Jesús Martín-Gil,Pablo Martín-Ramos,Jorge Martín-García,Julio Diez,Artur Alves,Glória Pinto

doi:10.3390/f9110685

Iosody Silva-Castro, Jesús Martín-Gil + Show 5 more

Open Access

https://doi.org/10.3390/f9110685

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Abstract

Pine pitch canker (PPC) is a major threat to pine forests worldwide because of the extensive tree deaths, reduced growth, and degradation of timber quality caused by it. Furthermore, the aggressive fungus responsible for this disease (Fusarium circinatum) can also infect pine seeds, causing damping-off in young seedlings. This study proposes an approach based on coating treatments consisting of natural products to ensure seed protection. Seeds from two pine species (the most sensitive to this disease, Pinus radiata D. Don, and a more resistant one, Pinus sylvestris L.) were coated with single and binary mixtures of low and medium molecular weight chitosan and/or ethanolic-propolis extract. The germination rate, pre- and post-emergence mortality, total phenolic content, and radical scavenging activity were assessed. All treatments, and especially the one based on chitosan oligomers, had a beneficial impact on P. sylvestris seedlings, significantly enhancing survival rates and displaying a positive influence on the total phenolic content and on the seedlings’ radical scavenging activity. Conversely, non-significant negative effects on germination percentages were observed in the case of P. radiata seeds. The proposed treatments show promise for the protection of P. sylvestris seedlings against PPC.

Highlights

Fusarium circinatum Nirenberg & O’Donnell is a quarantine fungus according to the European and Mediterranean Plant Protection Organization (EPPO) [1] that causes pine pitch canker (PPC)and which has been deemed as one of the most damaging pathogens for Pinus spp. throughout the world [2]
The highest germination percentage (GP) (85.7%) for P. sylvestris was attained for the control and propolis ethanolic extract (PEE) treatments
The study presented demonstrated that the application of bioactive coatings based on chitosan and propolis could be helpful for protecting certain Pinus species’ seeds against F. circinatum

Summary

Introduction

Fusarium circinatum Nirenberg & O’Donnell is a quarantine fungus according to the European and Mediterranean Plant Protection Organization (EPPO) [1] that causes pine pitch canker (PPC)and which has been deemed as one of the most damaging pathogens for Pinus spp. throughout the world [2]. Fusarium circinatum Nirenberg & O’Donnell is a quarantine fungus according to the European and Mediterranean Plant Protection Organization (EPPO) [1] that causes pine pitch canker (PPC). In forest nurseries, F. circinatum causes pre- and post-emergence damping-off, wilting of seedlings, shoot and tip dieback, and it leads to the death of the infected seedlings [3]. F. circinatum can be found in nurseries of North and South America, South Africa, Asia, and Southern. The use of seeds from orchards poses a serious threat of spread of this fungus to nurseries. There are no effective means of controlling PPC in nurseries and forest plantations. An integrated management plan should include both adequate quarantine measures and appropriate nursery and silvicultural management strategies. The implementation of seed protection in nursery health practices would be of paramount importance

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