Effect of okra fruit blocks, seeds and pericarp on post-embryonic development ofEarias vittella (Fab.) in relation to some phytochemicals of selected okra genotypes
Post-embryonic development of the spotted bollworm,Earias vittella (Fab.) studied on pericarp, seeds and fruit blocks of 8 okra genotypes, revealed significant differences in larval survival, larval period, pupation and adult emergence among genotypes as well as fruit components. First instar larval survival on fruit components was in the order of fruit blocks> seeds> pericarp> axil. Mean total developmental period was 24·20, 21·33 and 21·09 days on pericarp, seeds and fruit blocks, respectively. Likewise pupation was 25·30, 65·42 and 71·58% on pericarp, seeds and fruit blocks, respectively. Primary phytochemicals, like protein, free amino acids, total sugars, non-reducing sugars and moisture content in pericarps were in higher concentrations in comparison to seeds and whole fruits. These compounds also differed significantly among genotypes. There were positive correlations between the pest survival and these nutritional compounds. Tannins were 0·35, 0·23 and 0·29% in pericarp, seeds and whole fruits, respectively. Tannin content was significantly higher in pericarps of tolerant genotypes and showed significant negative correlation (r=−0·81) with fruit borer survival.
Ram Singh1 2