Why do the leaves and fruits of my greenhouse tomatoes have papery brown patches on them?

Some of my greenhouse tomatoes have pale-brown patches on them.

Sow ageratums, aubergines and greenhouse tomatoes in a heated propagator.

Economically, the upside of bumblebee pollination includes enhanced yields, reduced costs of production (previously greenhouse tomatoes were pollinated by humans wielding vibrating 'wands'), and perhaps even tastier fruit.

Sometimes, greenhouse tomatoes fail to ripen properly and parts remain green (usually at the stalk end) or yellow.