questions: asking about control of corm weevil and  stem weevil 
 answers: advised him for corm weevil 
apply carbaryl 10 – 20 g/plant in the soil around the stem.
stem weevil 
spray malathion 50 ec @ 2 ml/lit of water. 

alternatively, dilute 54 ml of monocrotophos 36 wsc with 350 ml of water and inject 4 ml (2 ml at 45 cm from the ground level another 2 ml 150 cm from the ground level) in the pseudostem at monthly interval from 5th to 8th month.