what's happening to SP's new growth?

[Pachrian]

My Simple Pleasures is trying very hard to get bigger (it's in a 6" pot). Unfortunately something happens to the new growth as soon as it emerges. Is it insects or too much water? The poor plant is getting so bushy from losing all its tips and then trying to grow new branches, which is nice, but I'd just like the branches and leaves to grow.

Occasionally I see it on a few other plants too

[Doll]

I had this on my BonTemps shortly after I received it. It has corrected itself on my BonTemps. I think it is a fungus.

[Pachrian]

Uh-oh, fungus always sounds so bad to me. I'm glad it corrected itself for you, hopefully my problem will do the same.

[Charlie]

I see a little of this from time to time and, like on Doll's Bon Temp, it goes away as mysteriously as it arrives.

You could try changing the conditions - mainly more sun or less sun or more or less wind - since a lot of micro-organisms (which I think are involved in this) have a narrow range of conditions that they flourish in.

Charlie

[Pachrian]

Thanks, Charlie. I put the pot in the afternoon sun, hopefully that does the trick.

[Pachrian]

I finally caught the evil-doer in the act. I've seen him around, usually after I pinch off the affected tips. I noticed that if I don't pinch down far enough the stem is hollowed out. Also, and I don't know if it is just from the dried up new growth, but it seems I find poop-like grains in the area.

So, here he is...all 5mm of it.

Btw, Charlie, one of the new plants I brought home from open house had a tip like this also. So you might want to look out for these guys too Hopefully we can id what it is and find a good spray.

[roadrunner]

Great pics. I've never seen any literature about stem borers in hibiscus.  I wonder what it is a larva of?  Can you get a side view pic showing the legs or have you already pulverized the little monster?  Wonder if it's an imported pest.

dave

[Pachrian]

Stem borer? Thank you so much, Dave, it's so much easier to google for it if you have something else besides larva and hibiscus.

Yup, you guessed it...I squished him. I found this picture with a bit of a side view though. Funny, in all shots I only see the front 3 pairs of legs, this shot shows them the best.

[Charlie]

That's fascinating, although a little scary, too. I never saw anything like that. How did you happen to catch him in the act? Did you cut into the stems to look or??

If I learn anything about this I will surely share it. In general, the standard and least toxic way to treat for caterpillars is to spray any product containing BT (Bacillus thuringiensis), a bacteria that only effects certain insects like caterpillars. I have no idea if this creature will be susceptible to it but hopefully it would. Spinosad might also work. However, if the creature lives inside the stems it might be protected from sprays. In that case Safari might get to it if it feeds on plant sap.

Uli, thanks for these great photos!

Charlie

[Cindy]

Those are fantastic pictures, Uli!  Wow!  I just sent them off to an entomologist at UC Davis. Hopefully we'll be able to find out what they are.

Now I'm going to start inspecting every growing tip with a magnifying glass! Yikes!

Cindy

[Pachrian]

I agree, Charlie, it's a bit scary. My little bit of research has not come up with much other than that stem borers are not good and that researchers are still trying to find a way to get rid of them.

When I notice newly growing tips to change color I usually pinch them off. I noticed that often the remaining stem will be hollow and I pinch off a bit more. As I said earlier I have seen these larvae crawling around (my young plants are on a glass table which made it possible for me to spot the larvae that must have fallen off during pinching). When I inspected the pinched off tip today I noticed the little guy inside

Oh, and I should mention that the plant I brought home from open house which had the same  died off tip was a 4" Confection Perfection. So maybe you should keep an eye out where ever you had those and the 4" Simple Pleasures.

[Pachrian]

Cindy, I really hope this doesn't turn out to be a big problem...for you guys more so than me, of course. Keeping my fingers crossed this entomologist knows what it is and more importantly, what to do about it.

In the meantime I keep pinching...and creating some nice bushy bushes

[helixturnhelix]

Well its obvious that everyone loves hibiscus

[Charlie]

Uli, thanks for the additional info. As I mentioned earlier, I've seen unexplained die-off of the newest growing tips occasionally for years now. It's never been more than a few plants out of thousands which makes me think it is something like a moth that flies in, lays eggs on a single plant, and then dies. Larvae feed on whatever they hatch on and then build a cocoon and fly off as they emerge as moths. They don't spread from plant to plant and increase in numbers the way something like spider mites does. Also, I've not seen plant tip growth death progress into death of the host plant, instead we have seen the plant recover as mysteriously as the problem occurred. Our pesticide program creates an environment that is not hospitable to moths or other such insects sticking around. I've seen moths fall from the air dead when a spray of Conserve (for thrips usually) is directed at them.

Doing what you did seems the best answer. Pinch off the growth tip and a little of the stem to find the larvae and then dispose of it. Please keep us informed and with this new info I will watch out for anything resembling it in the greenhouse.

Charlie

[Cindy]

I checked all the known scary insects for our area, and this larva is none of them at least. I'll keep searching, and we'll keep a close eye out for more of those little critters. I had a little outbreak of bigger green larvae a few years ago in my house too. They were on only 2 plants that were together in a window, and I have never seen them again. So I think Charlie is right that moths or other flying insects fly in, lay eggs, they hatch and fly away. In the greenhouse they won't be able to survive as flying insects to start a new life cycle. The best they can do is fly in from outside and lay eggs for one cycle. I was afraid that they might survive in my house where I don't really use a pest control program, but they just flew away and didn't come back. Hopefully you can cut all yours off, and never see them again, Uli! We'll inspect every plant in the greenhouse for more of them too!