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

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.

White-Rot Fungi Control on Populus spp. Wood by Pressure Treatments with Silver Nanoparticles, Chitosan Oligomers and Propolis

“…Moreover, it has other very interesting properties, including biocompatibility, high biodegradability, bioactivity, and non-toxicity in humans [24,27]. Chitosan can be chemically and/or enzymatically modified [28] to prepare chitosan oligomers (pentamers and heptamers), which present enhanced antifungal behaviors [21,[29][30][31].…”

“…Partially purified propolis extracts have been investigated for wood protection due to their antimicrobial effects against yeasts, molds, bacteria, and parasites [10,32]. Propolis' activity against wood-decay fungi has been demonstrated in previous works [21,30,31].…”

Environmentally friendly methods for controlling pine pitch canker

“…Moreover, coating of propolis on seeds enhanced survival by approx. 45% of P. sylvestris seedlings grown in F. circinatum ‐infested soil (Silva‐Castro et al ., ). The resin of P. radiata and specifically five monoterpene components of this resin (limonene, α‐pinene, β‐pinene, camphene and myrcene) inhibited mycelial growth, or affected survival and germination of F. circinatum spores (Slinski et al ., ).…”

“…Prophylactic chitosan application reduced disease incidence in P. radiata seedlings subsequently inoculated with F. circinatum at low inoculum levels (100 spores per wound). Moreover, chitosan coating also enhanced the survival of P. radiata and P. sylvestris seedlings grown in F. circinatum -infested soil (Silva-Castro et al, 2018a). Systemic induced resistance to F. circinatum in seedlings of P. radiata treated with chitosan lasted c. 42 days (Reglinski et al, 2004) and 6 weeks in Pinus patula (Fitza et al, 2013).…”

The effects of salicylic acid, oxalic acid and chitosan on damping-off control and growth in Scots pine in a forest nursery

“…Research on CH, SA and OA as plant protection products and growth stimulants has so far concerned various herbaceous crop plants (Wang et al 2009, El Hadrami et al 2010, Rivas-San Vicente & Plasencia 2011, while only few studies have focused on woody plants, including forest trees (Reglinski et al 2004, Fitza et al 2013, Aleksandrowicz-Trzcinska et al 2015, Silva-Castro et al 2018a. The aim of this work was thus to assess the effects of these three natural substances on the control of damping-off and growth among Scots pines at a bare-root nursery.…”