Are there any controls for Cucumber Beetle.
They have to have a enemy
None that will have any kind of meaningful impact. It is not so much the beetles feeding that is the problem. It is the bacterial wilt and virus' that they transmit. It only takes a few infected beetles to kill an entire field.
The "best" control I have found, without blanket spraying every few days, is to use trap crops and only spray the trap crops and small perimeter around the trap crop. Blue hubbard squash is the favorite of cucumber beetles. If you plant a 100% perimeter (no gaps) of blue hubbard squash around your melons, the beetles will prefer the blue hubbard. You can then use IPM principals to know when to kill the beetles in the trap crop. This keeps the lions share of the beetles out of the main crop AND you reduce the spray amounts.
Whether you use organic sprays or conventional, the result is hopefully the same. Less spray on the food crop and hopefully less spray on the hubbard. If they don't kill the hubbard then you get a bonus crop to sell.
Seed is very cheap for hubbard as well so the cost to try this and see how it works in your field/location is a pretty low investment.
Yes, there is hope! I used to have terrible problems with cucumber beetles! I got beneficial nematodes and the next year I hardly saw a cucumber beetle. You see the cucumber beetle lays eggs in the soil and the beneficial nematodes eat their larvae.
Only a VERY SMALL amount of beetles will emerge from your own soil. The VAST majority migrate from southern states in the jet stream during June and July. There is no real bio-rational to control them effectively.
Cucumber beetles transmit bacterial wilt. It takes less than 10% of the cucumber beetle population to be infected to almost wipe out most cucurbits that are sensitive to it. Row covers, pyganic (more of a repellant now due to resistance), neem (mostly repellant) will help the home grower. It is NOT effective on a large scale.
I usually start by keeping a very clean field. NO WEEDS that beetles like to feed on. Transplant MOST crops. They are most susceptible when they are less than four weeks old. Plant trap crops and then spray the trap crops when thresholds for treatment are crossed. Lambda-Cyhalothorin is VERY effective at killing them dead. I usually start with Pyganic at the max rate. This works for ONE treatment. Any beetles left will be immune. Next spray will be lambda (Silencer, Warrior, etc.). This is USUALLY enough to keep them under control until the crop is in.
For those people who like systemics, you can buy seed treated with Farmore and that will take care of many of the larval versions. It will kill adults too, but once they feed on the plant any bacterial transmission will have occurred and your screwed even if the bug dies.
The only beneficial I would work on improving would be bats. They are VERY effective at eating huge numbers of beetles.