Hi
Use yellow and blu color sticky traps which will attract white flies, thrips, leaf minors, jassids which otherwise severely infest Cowpea
Spray Carbendazium 1 g/Ltr + Fipronyl 1.5 ml/Ltr to take care of Pest/Diseases
Drench with humic acid @ 2 ml/Ltr, you can give with drip for better crop performance
During flowering use LIBREL micronutrient spray @ 2 grams/Ltr for better fruitset and higher seed yield and quality
Regards
Harish