On our national gardening show (on ABC tv) Peter Cundall was talking about pumpkins, and said growers should not to be reluctant to pinch off the tips of long runners, this forces side runners to grow and it is these side runners that bear the female flowers. So you will have more pumpkins if you pinch off the tips of the main runners.
Anyone heard of this before?
Note: Americans would refer to these as "winter squash", I think.