There are many bugsthat I never see that damage plants, I pick on the ones I find. Two of the most common are the cucumber beetle and the Mexican bean beetle.
This bug is also pictured in discussions as one state of the corn root worm, but I' don't know if this is correct. Anyway, this beetle eats leaves, particularly of beans, and is a special threat to seedlings.
The Mexican bean beetle is so like the cucumber beetle that I wondered at first if there was a difference. I noticed that the Mexican bean beetle shows up early and disappears, then the cucumber beetle takes over in a big way. They both affect seedlings as well as more mature plants.
The two differences between these two beetles are:
I tried spraying a 0.5% solution of Neem oil on beans this year. The kicker is that Neem oil doesn't repel bugs - it only affects them once they have had a few bites of the plant leaf that is covered in Neem oil.
My prime need for protection from bugs is just after they poke out of the soil. A single beetle can effectively kill a seedling.
I can't be sure of any success I have had with the Neem oil.
There's quite a circus of bugs in the garden, some quite attractive. I don't know the names of many.
Here is a gallery of bug photos.