Killing Cycad Scale With Coffee Grounds
In the spring of 2012, my beautiful (before Aulacaspis yasumatsui cycad scale) queen sago (Cycas rumphii) was beautiful no more. All the leaves were covered with scale, and the fronds were cascading, dying-like, all around the trunk. I am not showing you what the plant looked like as I am somewhat humiliated at the sight of it. However, if you have one in trouble, you already know what it looked like; even so, you can find pictures of inflected plants on the Internet.
I had tried all that I knew to kill the scale—several kinds of oils, scale insecticides, flea and tick spray, and a strong stream of water. The water treatment worked best, but the plant was suffering badly from year to year. Furthermore, with any of these, I had to treat the plant over and over. Nothing killed the little buggers completely. Searching the Internet, I came across an article by Tom Broome, who suggested using coffee grounds.
So, with seemingly little to lose, off to Starbucks I went to see if I could get some of their spent grounds. It’s hard to believe, but they are glad to give the grounds to anybody just to get rid of them. Believe me, spent coffee grounds are like gold to us cycad scale victims.
My Simple Coffee Grounds Experiment
My cycads suffered terribly during the winter of 2011/2012. They had been slowly dying over the previous 4 years while I fought the dreaded scale Aulacaspis yasumatsui. I had been able to keep them barely alive using a jet spray from the hose, cleaning leaf to leaf, top side and bottom side. During that winter, two of the younger plants died. I knew something had to be done, or I would lose all of them. So, I decided to cut all of the offending leaves off. A smaller pup that I had been grooming for years had just put out new leaves, and since it was winter in Florida, they didn’t have many scale insects on them, so I left those leaves alone. (See photo.) The larger mother plant was covered, and I cut off all those leaves. The small pups on the side that I hadn’t cut off I left, even though they had scale all over them and several had died.
About this time, I found the article by Tom Broome, who used coffee grounds to kill the scale. My wife who drinks coffee and loves Starbucks got me two bags, and I used one to make coffee grounds tea and another to put the pure grounds on the plant.
I made tea and sprayed it on the scale, but I saw no change in the next week or so, and I assumed it had done no good. I don’t know if it did or not, but I found out later that I didn’t need the tea anyway.
Finally, feeling somewhat defeated, I started just globbing coffee on the crown of the cycad. Starbucks includes the paper filters in the bags of grounds, and they come in handy for what we want for our cycads. It’s messy, but I took out the papers and intertwined them around the bases of the old leaves in order to help hold the coffee grounds in place. It worked like a charm. Most of the grounds were still there three months later after many waterings and a good rainy season.
I did the same for the large pup, cutting off some old leaves, but I left the brand new leaves. Then, the crown was packed just like the mother plant.
For the mass of smaller pups on the side, I just put grounds in every crevasse I could find. I had some grounds left and just put them on the ground around the base of the plant.
A note about infected fronds: The surfaces of the fronds facing directly to the sun seem to be comparatively free of scale even with the undersides virtually covered. I attribute this to their vulnerability to ultraviolet rays, although the scientific proof is probably not available. (If this interests you, check out this article on how UV light kills cells.)
I let the plant grow new leaves during the 2012 growing season without any interference, and there was little scale, but the leaves were still of the shorter variety we get used to with the scale. By March of 2013, I had my first leaves without any scale. I then packed the crowns with coffee grounds as before, preparing the plant for another growing season.
During the summer, I had the most growth I have ever had with the resulting beautiful Queen Sago that you see below. Needless to say, I am delighted!
I know you might think that I slipped a ringer in on you, but this is the same two plants and pups as we started with. Notice that the fronds are all of the healthy, deep green, shiny, long variety, even those from the pups. The plant was fertilized twice, once in May and again in September, and we had a good rainy season this year.
As you can see from the next two pictures, the scale is completely gone.
For me, this little study is enough “proof” that coffee grounds can be used to protect cycads from the cycad scale Aulacaspis yasumatsui.
I would recommend that botanists consider doing some research on the subject. Furthermore, insecticide researchers might consider looking at the insect-killing ingredient in coffee that produces the results noted in this article. I would not be surprised to find more uses for coffee grounds in our quest for happy, healthy plants.
There are many kinds of cycads that you can raise, both indoors and outside or in pots and in the ground, but this article deals only with the Sago Palm. There are other cycads that are immune to scale infestation.
You might find cycads at some local nurseries, but up north they probably would not be readily available. If you have a friend who has a mature plant, usually one that is planted in the ground, it might have pups on the side that can be cut off. They are very hardy and usually grow easily.
Growing a cycad in a pot as a bonsai makes a beautiful presentation, although they grow better in the south outdoors in the ground.
Research on the Internet
The research, whether university scientists or unscientific storytellers (as this work is), runs from completely ignoring coffee to wondering if it might work to exclaiming at the wonderful way it does work. However, a definitive scientific study is still to be completed. Reading the following websites and following up on the citations will give you a good idea of the problem at hand.
Cycads Overview: A surprisingly well done summary with an abridged bibliography of cycads can be found at Wikipedia.
Coffee, Cycad’s Newest Best Friend: This is the groundbreaking article by Tom Broome found in The Cycad Newsletter 30(4) December 2007, page 46, which describes his experimentation with coffee grounds. Mr. Broome is the owner of The Cycad Jungle in Florida, and his article shares the methods he uses with grounds and ground sprays. For cycad lovers over the world, this article is worth printing out and keeping close at hand. It can be the saving of your magnificent cycads.
This content is accurate and true to the best of the author’s knowledge and is not meant to substitute for formal and individualized advice from a qualified professional.
Questions & Answers
© 2014 Wes Rouse