Our raspberry plants were very productive this year but now are being eaten alive by Japanese beetles. In Zone 5, is it too early to cut them way back to hopefully decrease this menace, and prepare them for next year's crop?
Well sure you can, but don't cut down next year's crop if summer bearing. And you will lose the summer crop of fall bearing types. Some fall bearers only have small summer crops, others huge summer crops. For example Fall Gold has a huge summer crop. What an excellent raspberry! And since you have the beetles now, your lawn will be full of grubs no doubt. And next year they will all hatch and if you think this years is bad.... Better kill the grubs, nematodes is organic and right now is the time to use them.
you don't say the variety, so I don't know if there are more berries to come. In my area the japanese beetles are wrapping up. So I would leave them. As stated you need to deal with the beetles. What I do is use beetle traps away from the good plants and I have a pan of soapy water that I knock bugs into from my good plants. I keep the soapy water water at the good plants, and hang the bags of dead bugs in the good plants. I learned this trick by observation, live bugs attract other live bugs, but dead repel. So you have to be fast to knock them into the soapy water once you have other dead ones in there. The dead repel is not 100%, but it clearly helps. Same with have in a bag of dead in your trap, it slows it way down in catching.
Thanks for the responses. Not sure of the variety other than they are summer bearing. Most beetles gone but moles are working overtime! Drew, you say cutting back now would destroy next year's crop....sure don't want to do that so I guess best leave them alone. Right now they are growing "wildly. I have taken out most of the older canes to clean up the patch a bit.
With summer bearing cut out an canes that fruted, and the canes that have not fruited leave alone. And you can thin them out. You want canes about 6 inches from each other. Any weak, dead canes can be pruned out. Even good ones if too close to each other.