Development of Sitotroga cerealella (Olivier) on certain cereal grains in Botswana

Abstract

The development of Sitotroga cerealella (Olivier) was studied on maize (kalahari early pearl and yellow maize varieties), sorghum (segaolane and sephala varieties) and millet (serere 6A and legakwe varieties), under ambient laboratory conditions (temperature range: 25-30 °C and 64-70% R.H.). This study was done on whole, broken/cut and ground grains. The mean developmental period of S. cerealella on the food commodities ranged from 26.67± 0.70 days to 50.40± 1.90 days in legakwe whole and ground millet, respectively. The sex ratio (male: female) of S. cerealella ranged from 1:1 (millet: serere 6A), 1:1.06 (sorghum: sephala), 1.12:1 (sorghum: segaolane), 1.39:1 (millet: legakwe) and 1.82:1 (maize varieties: KEP). Egg hatchability was observed to be 81.7%. The mean adult longevity of males ranged from 5.62± 0.26 days on broken legakwe millet to 9.42± 0.48 in segaolane sorghum, while longevity of females ranged from 6.31± 0.54 in serere 6A to 9.73± 0.75 in legakwe millet. The average percentage damage for two months storage period caused by S. cerealella on kalahari early pearl maize was 4.99% and 5.38% on segaolane sorghum.