Host plant preference of army worm (Spodoptera litura) on crops and weeds.
A study was conducted to determine the preference and host range of a polyphagous lepidopteron, Spodoptera litura, collected during a search for biocontrol agent of Trianthema portulacastrum L. Culture of S. litura was maintained on T. portulacastrum leaves at 26±2°C and 70±5% RH. The experiment was done using 10 days old larvae of S. litura obtained from the laboratory reared nuclears culture. Forty five plant species of crops and weeds belonging to 21 families were used for host preference study. In each replication, 10 larvae were placed on bouquet of various crop and weed plants in well aerated large size containers (2×3×2 ft). Out of the 45 crop and weed plants tested, larvae of S. litura showed high, moderate, low and nil preference for 15, 12, 7 and 9 plant species, respectively. Among the crop plants, maximum preference was observed on Lycopersicon esculentum Mill., Spinacea oleracea L., Brassica oleracea L. var. capitata and Trifolium alexandrium L. Among the 25 weed plants tested, high feeding preference was observed on Alternanthera philoxeroides Mart., Euphorbia hirta L., Eichhornia crassipes Mart., Trianthema portulacastrum L., Parthenium hysterophorus L., Cichorium intybus L., Rumex obtusifolius L. Chenopodium album L., and Ipomoea fistulosa Mart.