One of my Prime Ark Freedom blackberry plants began to slightly wilt from the top. This was the tallest of the 5 and had bud clusters. I thought maybe it was heat stress or that had been shortchanged on water the last go round. So, watered it well. Next day it was more wilted. There appeared to be 2 girdling marks just over an inch apart a bit farther down the cane, but they were not from hitting the sides of its protective cage.
Today it was in worse shape. My worst worry was that it was a bacterial or viral infection. I cut through the cane just below the top “girdling”. It was hollow with what appeared to be a moist brown fras I didn’t know whether young blackberry canes were supposed to be solid or hollow, but suspected that it should be solid. When digging slightly into the hollow portion of the still standing cane where there was more brown frass, I found a small white “worm” with a brown head. If I’d had presence of mind, I would have saved it and had someone snap a pic, but I removed and immediately squished the pest between my fingers in retaliation. I then cut off a bit more of the cane in case there were more, since there had been 2 girdling marks. At that point, it was still slightly hollow, but there was no more frass. I didn’t find another wormy invader. I was also reluctant to cut any lower because I’d already brought it down to around 2.5 ft. just above a leaf joint.
The questions are - What lays eggs inside blackberry or raspberry tender growth? How do I avoid and/or eliminate this pest. What does the adult look like? Do I need to hack this back even farther.
The neighboring plant also had a visitor on top. In this case it was a very tiny preying mantid - just a baby. Where there is one, there are usually hundreds more.
The raspberry cane borer is probably the least common of the three borers
in our area. It also has a two year life cycle. From June to August the adult
beetles, after laying an egg in the cane, girdle the cane just above and below the
egg puncture, causing the tip of the shoot to wilt and die. After hatching, the
larvae tunnel down a short distance past the point of girdling and then
overwinter. The following season the larvae continue boring to the crown. If
pruning is done within a few days after the characteristic wilted tips appear, only
the wilted tip and a few inches below it need be removed.
I had that one year and was Internet diagnosed as a cane borer. I pruned off a couple of inches below each one and inspected each cane and pruned any with the girdle marks even if not wilted.
I thought I was giving too much info, but from what you said and the link, it describes exactly what I saw. Looks like I did the right thing. Figures that I’d get the least common my first year with them.
I did check all bramble canes after that & didn’t see more. I guess I’ll have to do this very frequently now.
Argh! Found another one this afternoon. Again it was on a PAF (Prime Ark Freedom) - the next one over. This time, though, it wasn’t on the main cane, but on a the young top side branch. It snapped right off on the lower girdle when I touched it.Opened it up and saw that the egg hadn’t even had time to hatch. If it did, the worm was still too small for me to see. Top and bottom inside the section were still solid. The leaves hadn’t even wilted, yet.
Is there any way to control these borers outside of giant enclosures around each bramble? (The enclosure thing isn’t going to happen, anyway) I don’t think it will be possible for me to patrol every branch of everything each day.
I have the same problem here with the PAF blackberries.
This is the Raspberry Cane Borer (Oberea bimaculata).
Guess she really likes not having any thorns to deal with.
They bore down fast, Just a few days and they hatched and were 2 ft down the cane.
You can use pyrethrin but it will need reapplying after rain.
I tried a bit of Monterey white oil to see if the oily texture and smell would make her think i wasn’t a blackberry.
The Joy of bugs in the garden continues…
I swear I could start a blog A BUG A DAY and not run out for 5 years.
My first two years of growing blackberries went well. Then the bores started showing up and I lost about 80% of my berries. I’m still learning to deal with the borers but I feel like I’m making progress. After they invaded my plants I started cutting the borers out as soon as I saw the swelling. The first year I cut about half my canes out which set my plants back. This year as of now I have not seen any swelling and I feel like I’m in a recovery mode. Good luck, Bill
I’m attempting to outsmart the borers but right now they seem to have an edge on me. One of the things I’m trying is to head my vigorous varieties such as triple crown and natchez back to 6-10" and force several branches on each crown instead of one or two. My thoughts were to still cut out the borers as they are noticed and let the remainder of branches grow. The triple crown is a vigorous plant and puts out many branches. It is to early to determine if this method will help. Bill
Bill, I’ve been examining every cane, every branch, and every leaf stem every day. After the first two days, there was one day when I didn’t find any. Then next day there was one on a Navaho prmocane, and one of the raspberries. The following day there were so many that I lost count. Somewhere over 10 but less than 20, mostly on the tender raspberries. It was painful to pinch the blossom and fruit bearing tips off of those raspberries! I’m only going to get a few handfuls of berries from those little first year starts, and I had to sacrifice so many of them in order to give them a chance to make it until next year. I think we both know it’s a gamble to get those beauties to survive and produce the following year here in the southeast. I knew I was destroying the “sure thing” to have a chance at the long shot. Since that day I’ve only found 2 more. I haven’t found any new ones for 3 days now.
I believe that sine finding that first borer, all of the others have been fresh strikes with no opportunity to hatch. I’ve gotten them before any wilting or swelling, and the stems below them have been solid. I believe this is because as soon as I see the thin marks where the adult attempted to double girdle the stem, I’ve removed them. There hasn’t been an actual worm in any after the original find.
I haven’t sprayed them with anything but water to remove aphids and whiteflies. Mostly, I’ve just been hand crushing those. I looked up other state extension office recommendations for commercial growers and other than destroying plants, it seemed the most appropriate recommendation that would apply to home growers was to apply a systemic in the fall.
Here’s hoping that the borer’s egg laying season is a short one. The PAFs that I first had to trim have started putting out laterals. So, they’ll be shorter overall, may wind up with no actual loss.
I snap the wilted tops off below the larvae. Then snap where the larvae is and hang it up to dry it out. Last year I threw them all in the trash. This year seams like 75% of my raspberries are wilting!!! I even sprayed but they keep on coming. The canes will keep on growing with a new bud.