A novel format (Fig. 2) was designed for RIGS kit, so that it enables the detection of TBSV on a single strip. Thecolloidal-gold-conjugated solution of antisera raised against TBSV was mixed in equal quantities and applied on 26 × 1.7 cm conjugate pads (Standard 14) and dried under dry air for 10 - 15 min. TBSV IgG–ovalbumin conjugate was diluted in 0.02 M sodium phosphate buffer, (pH8.0) containing 1% sucrose to a final concentration of 2 mg/mL and applied as a 0.5 mm thick, 26 cm line, centrally
at 1.25 cm from the top and bottom ends on one side of a 2.5 × 26 cm nitrocellulose plastic backed membrane strip, using a locally fabricated airbrush device (Innovative Biosciences, India). Nitrocellulose membrane was cut into sections (2.5 cm × 26 cm). Test line was coated with TBSV-IgG conjugate, which was applied to each membrane in 1 g/L TBSV using TLC conjugate sampler (Sambrook
et al., 1989). The distance between the test line and control line was 6 mm. The test strips were dried at 37oC for 30 min. TBSV IgG–ovalbumin conjugate was diluted in 0.02 M sodium phosphate buffer (pH8.0) containing 1% sucrose to a final concentration of 3 μg/mL and applied as a 1mm thick, 26 cm line, at 0.5 cm from the top end of the membrane. The membrane was dried at 50oC under a dry