Evaluation of phytotoxicity indicators of cowpea seed treated with selected botanical insecticides

Abstract

Phytotoxicity is a major problem associated with the preservation of seed with synthetic insecticides. Thus, the aim of this study was to evaluate the safety of some selected plant derived insecticides on treated seed. Seed of SAMPEA 11, SAMPEA 14 and SAMPEA 12 were each divided into five (5) lots of 50 grams/lot identified, as L1, L2, L3, L4 and L5. L1 and L2 were treated with 50 and 12.5 µg/mL of myristicin and alpha-humulene based-insecticides respectively. L3 was treated with 6.25 µg/mL of azadirachtin based insecticide. L4 was not treated, while L5 was treated with diluted chlorpyrifos. In SAMPEA 12 and 11, the catalase activity and seed protein content were significantly (P<0.05) reduced compared to what obtained for L4. While in SAMPEA 14, catalase activity was not significantly (P>0.05) different from that reported for L4. Similar trend was observed on the protein content of the said cultivars treated with the aforementioned botanical insecticides. This study established similarity and variation in varietal responses to the effect the aforementioned insecticides to which the studied seed of cowpea cultivars were exposed to.