NUTRITIONAL INDICES AS AN INDEX TO ASSESS THE FEEDING POTENTIALS OF FOREST INSECT PESTS, DEREODUS DENTICOLLIS AND MYLLOCERUS VIRIDANUS

Feeding preference of forest insect pests such as Myllocerus viridanus and Dereodus denticollis was studied using teak and acacia leaves in laboratory condition by analyzing the nutritional indices such as consumption index (CI), approximate digestibility (AD), efficiency of conversion of digested food (ECD) and efficiency of conversion of ingested food (ECI). The insect pests were collected from the plantations and maintained in the laboratory. Three types of experiments were conducted to understand the feeding potentials of the insects. In the first experiment, Dereodus sp. was fed with teak leaf for 24 and 48 hrs. In this experiment ECD and ECI were higher than the AD and CI.   In the second experiment, Myllocerus sp. was fed with the teak leaf where the ECD and ECI were very less when compared with the results of the first experiment. The third experiment showed the efficiency of the feeding nature of the Myllocerus with Acaica leaf where the food ingestion and food digestion were higher than the other two experiments whereas the AD and ECI were low when compared with the first two experiments. Food preference was assessed based on the results. Probably the Myllocerus prefers mostly the acacia leaf than the teak leaf.  The feeding potential indirectly reveals the nature of damage to the host plants. The results revealed to devise the strategy to control the plantations to avoid further damage in the form of growth and yield.