Keywords: Sitophilus zeamais, IPM, storage structure, botanical and chemical pesticides

Varietal screening, comparative study of storage structures and evaluation of botanicals were conducted to find out the eco-friendly and suitable management of maize weevil from February to May 2006. Studies were carried out in Entomology Laboratory of the Institute of Agriculture and Animal sciences, Rampur, Chitwan. In varietal screening, seven varieties, viz. Pool-15, Pool-16, Sheetala, Arun-4, Pool-17, Upahar and Manakamana-1 were tested under no choice condition in Completely Randomized Design (CRD). The numbers of F₁ progeny were low in varieties Pool-16 and Manakamana-1. They were less preferred varieties and had less damage (3.67% and 4.33%, respectively), where as Sheetala (15.33%) was the most preferred variety by the weevil. In comparative study of storage structures, five structures were included and 20 weevils were inoculated as a test insect in each treatment. Jute bag with inner plastic lining was found the best structure in all aspect for the tested period of 75 days. There was less weevil population (85 adults), damaged grain (10%) and weight loss (2.89%). The highest weevil population 148 and 141, more grain damage 18.5% and 18% and more weight loss 5.68% and 5.3% were found in plastic jar and plastic bag, respectively. In the evaluation of botanical pesticides, six botanical origins and one chemical 'malathion' were tested against maize weevil. Botanicals were treated at the rate of 10 g/kg of maize grain, where as malathion was treated at the rate of 2 g/kg of maize grain. Among the tested botanical materials, bojho (Acorus calamus L.) rhizome dust (powder) was highly effective in weevil mortality (100%), weevil population (0), 100 grain weight more (32.81 gm), less grain infestation (1.33%) and nominal weight loss (0.25%) superior to other botanicals, which were at par with chemical pesticides malathion. The black pepper (Piper nigrum L.) was also effective botanical pesticide for weevil mortality (66.67 %), less weevil population (185 adults), and less net weight loss (5.98%) as compared to other botanicals neem (Azadirachta indica A. juss), bakaino (Melia azedarach L.), eucalyptus (Eucalyptus spp.) and timur (Zanthoxylum armatum DC.). These four botanicals were not effective in weevil management. The integration of tolerant maize varieties, suitable storage structure and effective botanical pesticides like bojho (Acorus calamus L.) could be effective method for the management of maize weevil. This study has indicated ample scope of management of maize weevil using botanical materials along with the integration of suitable storage structures.