The
stomach pain was so bad in US, that I stopped eating water melon
from California. The
stomach pain in France was different, intensity was less, and depended on "melon". Earlier , first coming "primers" melons, especially from Spain and Italy were the worse...
Conclusion: something is about agriculture and not the Melon itself.
Last month I visited my mother in Moldova, and driving near a field of melons, I could not drive by....and stopped.