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Subject: Others × Author: Sonowal, Supriya × Start date: 2017 × Type: Thesis × Thesis Type: Ph.D ×
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    ThesisItemOpen Access
    Efficacy of nano bioformulation for the management of red spider mite (Oligonychus coffeae) in tea
    (2021) Sonowal, Supriya; Sahewalla, I. P.
    The present investigation was conducted in the Department of Tea Husbandry and Technology, Nano Lab of Department of Plant Pathology and field experiment were conducted in Experimental Garden for Plantation Crops (EGPC), Assam Agricultural University (AAU), Jorhat, Assam during 2016-2020 to carry out the experiments to obtain nanoparticle and characterization. The nano particles were synthesized from Fusarium oxysporum, fish and crab and used as NP-1, NP-2 and NP-3 respectively. The nanoparticle used were characterized by UV-VIS, Zeta Sizer, TEM and DLS. UV-VIS spectroscopy of chitosan nanoparticles was carried out a range of wavelength of 314.00, 340.00, 348.50 nm 200- 600 nm and results showed maximum absorption at critical wavelengths for a particular nanoparticle respectively for F. oxysporum, fish and crab chitosan nanoparticles. Zeta potential values of the present nanoparticles were recorded positively charged with zeta potential of 3.85, 16.89 and 20.48 respectively for chitosan nanoparticles of F. oxysporum, fish and crab. Similarly, TEM study showed the present nanoparticles were smooth surfaced with spherical in shape. On the other hand DLS study showed the size of the nanoparticles as 105.6, 98.0, 285.0 nm respectively for F. oxysporum, fish, crab. In vitro evaluation of chitosan NPs synthesized from F. oxysporum, fish and crab in combination of M. anisopliae and V. lecanii against red spider mite was tested at different doses (5 ml/lit, 7 ml/lit and 10 ml/lit) at 100 ppm concentration. At first day after treatment highest per cent mortality recorded from M. anisopliae + NP-2 (38.55%) at dose of 7 ml/lit. At third days of spray the highest per cent mortality was recorded from M. anisopliae + NP-2 (65.42%) at 7 ml/lit .This was followed by M. anisopliae + NP-2 (58.79%) and (58.05%) at 10 ml/lit and 5 ml/lit respectively. At fifth days after treatment M. anisopliae + NP-2 showed maximum mortality against O. coffeae (81.66%) at 7ml/lit followed by M. anisolipae + NP-2 (79.76%) and (76.48%) at dose of 10 ml/ lit and 5 ml/lit respectively and lowest mortality per cent (21.51%) was observed at control.