I use Rhubab water as they don't like the smell, however after heavy rain the fluid has to be reapplied, works for me and it's free.
Just put Rhubab leaves in a barrel, top up with water, allow to rot, when it smells awfull, apply with watering can. Water can be sived through tights or HGV Air filter to stop the watering can from clogging too often.
Improvise, adapt and overcome.
All the best to all,
Fred P xxx