Biosynthesised silver and copper nanoformulation as foliar spray to control bird's eye spot disease in tea plantations

Abstract

Tea leaves have economic importance in preparation of the popular beverage of the world "tea". Bird's eye spot disease of tea leaves creates significant revenue loss in tea trade of many tea plant cultivating countries. Management of this disease by silver (AgNps) and copper (CuNps) nanoparticles that are biosynthesised by efficient antagonists was studied. The biocontrol agents like Pseudomonas fluorescens, Trichoderma atroviride and Streptomyces sannanensis were evaluated for nanoparticle synthesis against Cercospora theae isolates namely KC10, MC24 and VC38. Initially, the freshly prepared extracellular AgNps showed high disease control (59.42 - 79.76%), but the stability of antagonistic property in stored nanoparticles were significantly high in CuNps (58.71 - 73.81%). Greenhouse studies on various treatments imposed also showed reduced disease incidence percentage of 13.4, 7.57 and 10.11% when treated with CuNps synthesized by P. fluorescens, T. atroviride and S. sannanensis respectively. Various treatment schedule in fields suggested the use of Bionanocopper@1.5 ppm for highest yield (3743 kg/ha) with 66.1% disease prevention. The results suggest the use of biosynthesised CuNps using Streptomyces sannanensis for controlling the tea plant pathogens causing foliar disease with higher stability in releasing the antagonistic activity during sporadic disease incidence of bird's eye spot disease in tea plants.

Biosynthesis of Silver Nanoparticles from Streptomyces Spp., Characterization and Evaluating of Its Efficacy against Phomopsis theae and Poria hypolateria in Tea Plants (Camellia sinensis)

“…69.90% was the highest percentage inhibition found against Poria on the 15th day of incubation by silver NPs at 5 ppm concentration in comparision with Carbendazim which showed 90.12% inhibiton of Poria at the same stage ( Table 2). The percentage inhibition of P. theae isolates which was high at initial stage for Ag Nps synthesized culture filtrate was in the range from 59.42 to 79.76%, followed by Cu NPs (43.66 -76.19%) [14]. Against Phomopsis, 67.47% was the highest percentage inhibition found by silver NPs on the 15th day at 5 ppm (Table 3), as compared with the green synthesized silver nanoparticles which were found highly toxic against pathogenic bacteria and fungi at a concentration of 30 ppm [24].…”

“…The average size was determined to be around 50 nm in size, similar to the analysis in which the biosynthesised Ag NPs and Cu Nps were determined using PS analyser. The curve reveals that Ag NPs were polydispersed in natue, with average size ∼250 nm [14].…”

“…Alternatively the biological synthesis of nanoparticles is eco-friendly, economic and appreciable [13]. The Cu NPs and Ag NPs biosynthesized extracellularly from the antagonists were characterized and its biocontrol activities was determined against P. theae which emphasizes and recommends the use of Cu NPs synthesized by indigenous biocontrol agent S. sannanensis for the control of bird's eye spot disease [14]. It has been reported that many kinds of metallic nanoparticles such as copper, silver, and gold show strong antimicrobial activities [15].…”

Effects of spraying nano‐materials on the absorption of metal(loid)s in cucumber

“…According to the study of Gnanamangai et al [9], it was found that the application of 1.5 ppm (1.5 mg/L) Bionanocper had the greatest effect on the yield of tea. At the same time, Mamyandi et al [10] chose the concentration of 1, 2, and 3 mg/L to study the foliar spraying of nano-iron.…”

The Efficacy of Green Synthesized Nanosilver in Reducing the Incidence of Post-Harvest Apple Fruit Brown Rot

“…However, [8] recently reported that green synthesis of AgNPs using plant extracts produces NPs that have different morphological characteristics, including sizes, stability, and electronegativity, which contribute to their bacteriostatic and fungistatic inhibitory potentials at significantly low concentrations. Black tea extract used in the current study for the synthesis of AgNPs is a brain stimulating beverage that is extracted from the leaves of the tea plant (Camellia sinensis), which is widely cultivated in several Asian countries [9].…”