Word definitions
manga: pumpkin
parira: give away
Translation
A white pumpkin gives away where the dark one lies.
Inspiration for proverb
A white pumpkin is clearly visible because of its color, giving away where pumpkins lie in a field. Without it, dark ones will not be easily seen.
Application
The revelation of one thing could give away other concealed related things.
OR
A group of related people could be identified or associated with the undesirable qualities of only one of them.