With the common and scientific names of the insect pest
These articles should help. Bitter leaf repels most insects, however the bitterleaf weevil (Lixus camerunus Kolbe) can be a problem.
https://www.gardeningknowhow.com/edible/vegetables/gourd/nigerian-fluted-pumpkin.htm
https://www.gardeningknowhow.com/ornamental/shrubs/bitter-leaf.htm
https://plantvillage.psu.edu/topics/pumpkin/infos
http://projects.nri.org/adappt/docs/Vernonia_factsheet.pdf