if the yellowing is more pronounced on the lower leaves and the yellowing progresses to browning and finally wilt, it may be fusarium. It is a common problem and the spores exist in the soil. Good sanitation and rotating cucurbits to another location will help. You can try solarization to reduce the fungal count and planting cucumbers in pots (preferably off the ground) in fresh potting mix
There are soil fumigants but most of those will require a license and are expensive.
Happy gardening in Hawaii. Gardens are where people grow.