Gross Pathology of SpliNPVs and Alterations in Spodoptera littoralis Boisd. (Lepidoptera:Noctuidae) Morphology Due to Baculoviral Infection*

Baculoviruses are invertebrate-specific pathogens and baculoviral infections cause alterations in the physiology, metabolism and morphology of insects. It is important to recognize these physiological and symptomatologic changes to understand baculovirus infection cycle and biology. For this reason, in our study Spodoptera littoralis Boisd. (Lepidoptera: Noctuidae) larvae were inoculated with the SpliNPV to doses of 3000 and 20,000 OBs for third instars and to concentrations of 10 6 and 3x 10 6 OBs/ml for neonates and the alterations due to NPV infection in larvae were then examined. Bioassays carried out with the third instar S. littoralis larvae revealed that no symptoms were detected during the first three days post-inoculation due to SpliNPV infection. Approximately, in the 4th day, infected larvae began to respond much more slowly than healthy larvae. This symptom was followed by whitening and slimming of cuticula, failure in molting, swelling of the body, diarrhoea, climbing to high places and hanging, liquefaction of the body and death. Infected neonates exhibited limited symptoms of distension and the failure of molting. The larvae died in approximately 8-8.5 days for third instars and in approximately 3-3.5 days for neonates due to baculoviral infection for the both doses and concentrations. On the other hand, different doses or concentrations did not cause an alteration in the occurence time of symptoms. To associate the NPV biology with the genes involved in baculovirus genome and understand their life cycle will improve their efficacy as biopesticides and help to the effective use of baculoviruses.