Relative abundance of insect pests and loss assessment of rice seeds at different storage conditions

An investigation on abundance of storage insects of rice seeds and loss assessment were made In Aman during February to July, 2002 and Boro during May to October, 2002 in different storage structures viz. Dole, Motka, Kolshi, Steel Drum, Kerosene Tin, Polythene/Plastic Bag, Gunny Bag and Plastic Drum at three villages of Mymensingh Sadar upazila. Analysis of seed sample of 250g from each storage structure at monthly interval showed four insect species namely, Sitotroga cerealella Oliv., Rhizopertha dominica Fab., Sitophilus oryzae L. and Tribolium castaneum Hebst. Higher insect population was recorded in Boro seeds. In Aman, the mean number of S. cerealella, R. domonica, S. oryzae, T. castaneum was recorded as 13.8, 2.1, 0.38, 0.6, respectively and in Boro, it was 18.6, 1.6, 2.7, 1.0 in 250g of seeds, respectively. The highest insect population, seed damage and weight loss were recorded in Gunny Bag and the lowest were in metal structures (Steel Drum in Aman or Kerosene Tin in Boro) followed by Polythene/Plastic Bag. Seed damage and weight loss was increased with storage period in Aman but decreased after initial increase in Boro. Highest moisture content was also found in Gunny Bag. More than 80% germination was recorded in all structures except in Gunny Bag in both seasons after six month. The germination was decreased with increasing storage period. Therefore, the storage structures, Steel Drum, Kerosene Tin and Polythene/Plastic Bag could be used for safe storage of rice seeds