Many of my cucumbers, after they shed the bloom are hooking, the ends
are turning up like a fish hook.

The variety is Burpless, I have bought my plants at the same nursery
for the past several years, they are planted where they were last two
years. I have read about this somewhere, but can't find it.

Is this caused by a deficiency(mineral), or maybe an insect or even
not using crop rotation(I have a special trellis built for them that
makes it difficult to use rotation.

Thanks for your help--SodB!