author(s)
Shiva Shankar Bhattarai

abstract
Laboratory experiment was conducted in completely randomised design to determine the inactivation curve that consisted of five different virus concentrations (20, 3.33, 0.55, 0.0925 and 0.015432 LE/l) of purified and raw type of viruses which were added with lignin (1%) to play UV (ultraviolet) protectant role and without mixing lignin were also prepared and again the solutions were applied to potato and egg bioassay. These solutions were subjected to artificial UV radiation through UV lamp for different time i.e., 0, 2, 4, 8, 16, 32 and 64 minutes. PhopGV larvas were harvested from different bioassays: purified PhopGV in egg, raw PhopGV in egg, purified PhopGV in potato and raw PhopGV in potato. Hiatt modelling gave the common intercept between the lignin treated and non-treated i.e., -1.53288 which indicated that there was no difference in the effect of lignin on the activity of different type of virus, i.e. raw and purified virus. The parameters of egg and potato bioassay i.e., intercepts, inactivation coefficients (k1, k2) and proportion of virus particles against increased resistance (log ) had the same value i.e., -1.53288, k1= 0.538571, k2= 0, 0.065673 and log  = -1.67081 respectively. This pointed out that these bioassays had no differences in the inactivation curves. Half inactivation speed with lignin was 4.58 days compared to 0.559 days without lignin in lab condition. The decrease in inactivation speed in case of lignin applied in lab condition proved the reduction of potato tuber moth with virus combined with lignin through the use of low dosage.