| dc.description.abstract | Tea looper (Hyposidra talaca) is one of the most important pests of tea and causes significant yield losses. Population of H. talaca in the field is affected by the presence of Nucleopolyhedrovirus (NPV). Nucleopolyhedrovirus is an entomovirus that infects caterpillar and causes polyhedrosis. Hence, it can be used as a biological agent for controlling tea looper caterpillar population. The objective of this research is to study the effect of instar and harvesting time of polyhedra on the production of polyhedra. The HtNPV concentration used was 1.59 x 107 PIBs/ml as an initial inoculum. Third, fourth, and fifth instar H. talaca larvae were inoculated and reared in room temperature, and harvested on the 4th, 5th, and 6th day after inoculation. Then polyhedra from different H. talaca instars and harvesting time were extracted and purified using differential centrifugations resulting in the partially purified polyhedra. The concentration of polyhedra from different instars and harvesting time was counted using Neubauer haemocytometer. Mortality rates on 3rd instar larvae were the highest because 3rd instar larvae were more susceptible to NPV compared to 4th and 5th instars. The concentration of polyhedra harvested from 4th instar larvae on the 6th day after inoculation was the highest. There was a signifigant effect of larval instars and polyhedra harvesting time on polyhedra production | en |
