Development and damage potential of Sitotroga cerealella (Olivier) (Lepidoptera: Gelechiidae) to different indigenous aromatic paddy varieties

The study was aimed to find the reaction of a major insect pest of stored paddy viz., Angoumois grain moth Sitotroga cerealella (Olivier) (Lepidoptera: Gelechiidae) to different indigenous aromatic paddy varieties. The grains of 11 paddy varieties commonly grown in Terai region of West Bengal (India) were evaluated in May-September in 2011 and 2012. The results showed that the insect completed four generations during the period. The favourable season for the development of S. cerealella was May-July when it takes only 29.17–35.21 days to complete the generation. The insect development was significantly fast in paddy variety ‘Gobindobhog’, ‘Kolajoha-small’ and ‘Mohanbhog’ (33.33, 34.35 and 34.59 days) and caused higher damage to grain number (5.05–6.51%) and weight (3.764.44%). The insect development was prolonged in paddy cv. ‘Tulaipanji’ (36.23 days) with less damage to grain number (2.99%) and weight (1.98%). All the developmental stages showed significantly negative relation with temperature but significant positive relation with relative humidity.