Kidney beeans

Not a spelling mistake! Just Lincs dialect!

Anyway, I went to my parents' today and my Dad took me to show me the kidney bean plants. I said it looked like they were coming along nicely but he said they weren't and he'd be lucky if he got a single bean from them! 

They have an infestation of rape beetle, apparently! He's tried soapy water on them to no avail, and doesn't know what else to use! He says the only chemical solutions that are effective are illegal!