cucumber plants have many leaves “laced” to the extent of tuning brown and falling off-a few spotted beetles

Question

I use neem oil and pyrethrins- nothing helps

Answer 1

Without knowing the insect that you are dealing with, I would suggest using Neem Oil to treat the plants.
These links have more information

https://www.gardeningknowhow.com/edible/vegetables/cucumber/protecting-cucumber-plants.htm
https://www.gardeningknowhow.com/edible/vegetables/cucumber/cucumber-beetle-control.htm
https://www.gardeningknowhow.com/plant-problems/pests/insects/leaf-miner-control.htm