RESPONSE OF COWPEA POD BORER, Maruca vitrata FABRICIUS (LEPIDOPTERA: CRAMBIDAE) LARVAE TO SPROUTED COWPEA SEEDS

Abstract

The effect of two sprouted cowpea seeds varieties (SAMPEA 7 and ‘Dan Shika’) and artificial diet (control) on growth and development of Maruca vitrata was determined for two generations (1st and 8th) in the laboratory. The aim was to identify a cheap source of diet for laboratory rearing of M. vitrata for scientific research. Fifty grams each of the sprouted cowpea seed varieties and artificial diet were infested with twenty-five 1st instars larvae of M. vitrata which were allowed to develop to adult stage. Data was collected on the growth and developmental parameters of the insect. The result indicated that the mean percentage larval survival in artificial diet was significantly higher (p<0.05) than the larval survival on SAMPEA7 and ‘Dan Shika’ sprouted seeds. The mean weight of larva on SAMPEA 7 sprouted seeds and artificial diet were at par (p>0.05) but significantly higher (p<0.05) than ‘Dan Shika’ sprouted seeds. The mean percentage pupa survival in artificial diet and SAMPEA 7 sprouted seeds were at par but were significantly higher (p>0.05) than ‘Dan Shika’sprouted seeds. The mean percentage pupal survival, larval survival and weight gain of the 8th generation was significantly higher (p<0.05) than the 1st generation. There was no significant difference (p>0.05) in mean percentage egg hatchability among the different Maruca diets and SAMPEA 7 sprouted seeds had the highest benefit-cost ratio (BCR) than other Maruca diets. The result indicates that SAMPEA7 sprouted seeds was as good as artificial diet in rearing M. vitrata, thus could be used as an alternative to artificial diet.