If I might offer a suggestion, perhaps feeding the afflicted plants with a complete, but lower nitrogen foliar spray once a week, starting the week they are planted might do a lot more that trying to deal with the pests later.
But do check the nitrogen level as too much nitrogen will make the problem worse...
That is a very good tip about nitrogen. thanks! I will consider it very much in the next season's planting. We are nearing Fall now so I will start in Spring. Have great days in gardening.
Actually it's the end of the season when the plants most need fed....
Unfortunately, I had to throw all the plants after I made the harvest especially when the planting season has ended. I need to clear the pot, remove the plant and roots and store the soil in containers for the next season. I can do what you suggest for the blackberries and the raspberry since I just leave them in their own pots in the balcony. They are winter hard so they can survive the minus degree temps. Thank you.