Chitosan for Plant Growth Promotion and Disease Suppression against Anthracnose in Chilli

Abstract

Chitosan is naturally occurring compound potentially used in sustainable agriculture to control plant diseases and enhance growth. An attempt was made to control anthracnose or ripen fruit rot of chilli caused by Colletotrichum capsici in the field under inoculated condition and to increase the growth and yield of chilli by different concentrations of chitosan as seed treatment and foliar application methods. C. capsici isolate "So" was found to be the most virulent against chilli at the time of pathogenicity test. Chitosan at 1% concentration was found to be most effective against the radial growth of C. capsici. Subsequently, seed treatment or foliar spray was done with C. capsici spore suspension (5×10 6 ml -1 ) and different concentrations of chitosan as per requirement of the treatments. Anthracnose or ripen fruit rot of chilli and postharvest disease incidence (DI) and percent disease index (PDI) were significantly lowest in the treatment T8, where seeds were treated with 1% chitosan combination with foliar spray of chitosan (0.5%) in pathogen inoculated condition. On the contrary, anthracnose or ripen fruit rot of chilli and post-harvest DI and PDI were significantly highest in the treatment T1, where seeds were treated with C. capsici. Germination percentage, growth promoting components, yield and thousand seed weight (TSW) were also highest in treatment T8 compared to all other treatments. As a result, the combined use of chitosan as seed treatment (1%) and foliar spray (0.5%) appeared to be most effective in controlling anthracnose of chilli and increased yield and yield contributing characters.

Influence of clam shells and Tithonia diversifolia powder on growth of plantain PIF seedlings (var. French) and their sensitivity to Mycosphaerella fijiensis

“…The combination of clam shells and T. diversifolia powder show a synergic action with dual role both as a biofertilizer and a biopesticide since they affect the growth promotion of PIF plantain seedlings and their protection against M. fijiensis in nursery and could probably enhance agricultural yield in the field. Indeed, the major compounds present in T. diversifolia are nitrogen, magnesium, potassium, flavonoids, sesquiterpene lactone and lk loi s… (Oyerin e et al, 2009), while the ones in the clam shells are chitin, calcium and magnesium carbonate, proteins, (Khoushab and Yamabhai, 2010) and they all activated the growth promotion and natural defense systems through the increased synthesis of nutrients and defensive metabolites (Mondal et al, 2012;Akter et al, 2018;Malerba and Cerana, 2019). This association for plantain PIF seedlings treatment revealed significant increase of growth characters and less sensitivity to BSD compared to the controls, confirming a positive effect compared to the individual effects of T. diversifolia alone and clam shells alone.…”

Potential Biostimulant Effect of Clam Shells on Growth Promotion of Plantain PIF Seedlings (<i>var</i>. Big Ebanga & Batard) and Relation to Black Sigatoka Disease Susceptibility

“…Such effects of shells or chitin-source treatments on growth promotion and/or host resistance have also been reported for other pathosystems such as cocoa/snail shells/Phytophthora megakarya [9], tobacco/nanochitin/Fusarium spp. [21], chilli/chitosan/Colletotrichum capsica [22], millet/chitosan derivatives/Pyricola grisea [23], tomato/crab shells/Fusarium oxysporum [24] and cocoa/oyster shells/P. megakarya [20] through the possible triggering of biochemical pathways associated with growth promotion and disease resistance [8] [25] [26].…”

“…Shells, chitin sources and derivatives (chitin and chitosan-based polymers) contents chitin, calcium and magnesium carbonate, protein … [10]. It has been shown that this content provides excellent protection against diseases and has influence on growth promoting components, yield, thousand seeds weight and reduced post-harvest disease incidence and percent disease index [8] [22]. Due to its high nitrogen content and low carbon-nitrogen ratio (C/N), chitin can be directly used as a fertilizer to enhance crop growth [8].…”

Comparative analyses of plantain vivoplants responses to different clam shells and Tithonia diversifolia treatments in terms of growth promotion and induced resistance against Mycosphaerella fijiensis

“…Indeed, the T. diversifolia liquid extract (T5) and T. diversifolia mulch (T4) have shown growth promotion and antifungal activities in the plantain vivoplants 3,8 as well as the other treatments (T3, T4 and T5) despite the less global impact [2][3][4]7 . The five treatments based on clam shells and T. diversifolia are organic matter that have been shown to activate the growth promotion and natural defense systems of plants through the increase synthesis of nutrients and defensive metabolites 15,16 . The organic matter provides nutrients to plants which participate in osmotic regulation, cellular permeability, and may act as structural components and essential metabolites of growth and development 17 ; but also, defensive metabolites acting in plant such as the biofungicide effect of organic matter highlighted on the susceptible Musa spp.…”

“…The area of leaves is impacted regardless of the condition by treatments T1 and T2 both containing clam shells. Indeed, clam shells are a rich source of chitin and derivatives that have been shown to influence on growth promoting components, precisely the chitin direct action as fertilizer due to his low carbon-nitrogen ratio (C/N) and high nitrogen content 15,16 .…”