From afar, this Purple Leaf Sand Cherry didn't have the usual deep purple leaves for this time of year. It was a dead giveaway of something wrong. Up close, I was in shock.
Sticky, bumpy and mouldy stems point to a major problem.
Black invaders were sucking sap on EVERY stem.
The worst on newer growth.
Then seeing scale nymphs all at the base too! These young, grey coloured, softer scale insects have emerged from underneath old brown female scale insects, and were making their way up the main branch to the tender stems to feed. This could be Lecanium Scale, but I am not 100% certain.
Here, you can see both sizes and life cycles. I am not sure if they have females which can reproduce parthenogenetically (without mating), but boy oh boy - there were thousands.
The females usually lay eggs in spring and the crawlers hatch from May to June in most species of Scale insects. Now, they molt and turn into instar (smaller juveniles) before becoming large adults. They feed by sucking sap and excrete honey dew which drips on branches below; causing sooty mould. It's quite the mess maker at this stage.
Here, I removed some large black females and you can see some nymphs coming from her underside.
HOW TO CONTROL
I made a tough decision:
A treatment of dormant oil before buds began to swell in March would of been ideal. It was too late.
Cutting away and removing from the location was the only way I could control such heavy populations of scale.
One small stem remained. In a few weeks time, many more will emerge again.
Thank you. Your information is the best with the pictures mixed with the simple descriptions. I looked at all the other sites, and I'm so thankful forr how you've presented yours. Diagnosis and solution were so easy to follow. and so specific. No threatening paragraphs overwhelming to understand.ReplyDelete
I am relieved to have your blog to come to when I have any other problem. Bravo!
Alaskan facing first illness and freaked out.
Thanks L.Susan Miller! I do this blog to help those of us who are all learning in the process! Don't freak out! lolReplyDelete
Thank you for your information I have this same problem with my sand cherry tree in addition to an infestation of ants going up and down the branches I am assuming one has to do with the other going to cut the tree down todayReplyDelete
Thank you for the information I am going to cut down my sand cherry tree today as I have the same problem in addition to an infestation of ants going up and down the branches I tried treating the ants with insecticide but they came right backReplyDelete
Given that it's now mid-July, folks, be aware that during the heat of the next month or two, the plant may not respond in the same way during cooler temperatures. Last year when I did this, it was a cooler, wet summer and the sand cherry did develop shoots from the base. This summer has been exceptionally dry and hot. Perhaps wait until next spring and try to dislodge some of the scale with a heavy blast of water spray. Cut harsh, right down in the spring. It will bounce back much more readily and not be stressed as it would this hot summer. Cheers.ReplyDelete
Thanks for this infoDelete
My Sand cherry is like all the rest mentioned here - just noticed the sap and mould on the edge pf my porch where the tree grows. I have been blasting with water and also wondered if the ants and the new infestation of giant black wasps in the soil below ( look like giant flying ants!)were related. Considering how hot its been this summer and calling for another heat wave this coming week, I will continue to scrape it/wash it away and cut down next spring. I would be interested to know how other people's sand cherries have done as these posts were 2 years ago...? did they come back healthy?
Hello Heidi, I work at a garden center in Toronto. A customer came in with a branch of a sand cherry that seemed to be going in to its fall colour. leaves look very similar as the ones in your photos but the branch didn't have any scales on it. Can't really seem to figure out what was wrong with it. just wondering if you had any ideas? Thank youReplyDelete
Hi there - trying to diagnose problems with Purple Leaf Sandcherry via wording - well, it won't happen. Purple Leaf Sandcherries are in "Prunus" family and have varying problems. Disease related and abiotic. Given this summer has been extremely dry and hot, Purpleleaf Sandcherries become susceptible to a variety of insect and disease problems - even dieback or another vascular disease. Sometimes, when it's so hot, the inner leaves change colour and drop. Hard to say over a blog conversation.ReplyDelete
http://www.apsnet.org/apsstore/shopapspress/Pages/42643.aspx This book would be an asset to have as a resource at your place of work. Try to source one.Delete
I sprayed my sand cherry with dish soap and water and blasted it with the hose numerous times. Some black bumps still remain but they appear to be dead. Now I'm spraying with watered down tea tree oil and hoping my tree is saved!ReplyDelete
CAN YOU TELL ME WHAT KIND OF DISH SOAP YOU USED? I HAVE TWO VERY SICK TREES -ONE IS TWO STORIES TALL THAT DESPERATELY WANT TO SAVE......Delete
Good! I would keep using the high pressure water spray and wash any remaining dead or eggs that may still be present. Keep the roots hydrated and perhaps mulch if you can! Cheers!ReplyDelete
We are in Thornhill, Ontario. We have the same conditions. This blog is great, but I don't want to cut it down :(ReplyDelete
I need to update this post, as the sand cherry is about 5 feet tall again. It took 2 years to bounce back. So, that is the risk to take if you want lush, thick growth again. If you don't want to cut it down, prune it back hard to secondary shoots. Rub off as many of the scale as you can with the water/soaking method and keep it watered during the heat. Add some good compost/shredded mulch to the base. This should help nurse it back. Pruning is quintessential to keep all sand cherries happy. They are like fruit trees. Pruning responses vary, but are beneficial in the long run. Cheers!Delete
Can this be a yearly problem? I'm wondering if it has anything to do with the health of my sand cherry or if it's more to do with weather. Are there any preventative methods you can take early spring to prevent this from happening again?ReplyDelete
I would love to see an updated picture of your sand cherry!
No, not yearly - but Purpleleaf Sandcherry bushes tend to be plagued with various issues as they get older. I was once told by a nursery grower that these bushes last about 15 years - tops. He called them his cash crop. We ordered them from his growing operation as his were the best! He mentioned it is key to keep pruning them, to encourage new growth. You see, we tend to plant shrubs and give them a lot of TLC and then forget about them once they are established. This is in error. One should prune regularly to promote good branching habit and good air flow between the stems. Adding compost or mulch at the root level would be the best thing. Also watering during drought periods. Scale attack weakened plants. A little more TLC will make the difference. Happy pruning.ReplyDelete
Hi Heidi. I reside in Whitby and have a small back yard with a small pond and purple sand cherry for shade from the summer sun. It was attacked by this black knot last year. I did prune as much of the branches as possible but would you suggest physically removing these little black knots in the spring if they reappear? Due to the roots and lack of space, I likely won't be able to plant anything else.ReplyDelete
Hi! I too am having similar difficulties with my purple leaf sand cherry. It distoryed my first bush I planted many years ago. It was beautiful then it slowly started dying. I noticed the black scale bumps all over it. I removed the plant all together. I waited a couple of years worked the soil and tried again with great results.ReplyDelete
Then summer of 2019 I notice my beautiful bush was infested again!!! So I did what you did and cut all affected branched off and carefully removed them in city garage. It’s slowly started again!!! Those black bumps. Not ready to give up I tried my own approach!
Last fall, I got my kitchen torch and blasted in quick strokes all over affected areas. The bumps either fell off or easily came off. I did my best to get them all. I excitedly checked this spring to see if they were back. There were some a couple of weeks ago so I torched those areas. I seems to have worked. Although it’s early days I am encouraged.
However I am now noticing orange ants all over the lower branches!!! I also notice they are coming in and out of small holes in thicker branches. Urge!! It can’t be good but are they harmful as well?
I’ll be sure to share results of my torching efforts in summer. Thanks for sharing this info.
Hi Heidi. I live in Ottawa and my sandcherry did not have the same problem, but it was very neglected and poorly shaped so last year I cut it down to about 10 inches from the ground. It's now May 22 and don't see any sprouts at all. Does this mean it's dead?ReplyDelete