Can somebody please help me identify this disease??

[Drewbis12]

I recently planted cucumber watermelon and tomato and they all are showing signs of some disease. I am very new to gardening and would appreciate help from anyone

[Drewbis12]

Here are more pictures

[ButterflyLady29]

Need more info. Are they transplants or were they directly seeded into the garden? It looks to me like a small case of sunburn or windburn which might be the case if they were transplants in the process of being hardened off.

[Drewbis12]

I grew them from seeds and transplanted them into bigger pots a few weeks ago I live in the Caribbean and it IS extremely sunny and windy