Curious line on a Brandywine.

Good morning everyone,  so what is the cause of this line on this standard sized Brandywine tom' ?  Cheers,   Tony.

P.S. Just put this beastie to bed to change into a pupa.  It's a Eyed Hawkmoth caterpillar Smerinthus ocellata  I think!

It's called 'zippering', and like 'catfacing' is usually caused by unfavourable weather conditions at the time of pollination and/or fruit development.

I've seen it from time to time on most types of tomato, although strangely enough, hardly at all this year, which has not been perfect for tomatoes by any stretch of the imagination!