Why are my pickling cucumbers yellow and malformed?
Hi- this is powdery mildew, a very common fungal disease of squash family members:
If the plant is producing fruit you can let it continue to grow. If not, and the disease is progressing rapidly you should pull it up and re-plant in the next two weeks.
Here's a website that will let you know about vegetable varieties with resistance to specific diseases:
It’s likely that the fruits are small and malformed and ripened prior to growing to their full and proper size due to poor pollination caused by low pollinator activity (not enough bee visits) or environmental conditions that damaged flower parts: https://extension.umd.edu/hgic/topics/pollination-problems-vegetables