Willow leaf ficus - leaf drop and droplets

[takira]

I obtained a wee willow-leaf ficus in August 2023 and it's seemed to be doing well. It lives outside in warm weather and moves indoors under lights for the winter. I have noticed that compared to my sturdy little Benjamina, the willow-leaf is a bit more...emotional? It's experienced significant leaf drop periodically over time, always in winter or right after I move it indoors, but never complete defoliation and it's always grown back.

More recently, it's dropped nearly all its leaves and the remaining ones look like they're going to go too. Also of note, the leaves had a sort of shiny, sticky-looking substance on their surfaces when they looked healthy - they had this for some time without any other seeming issues so I didn't do anything about it. Now that the leaves are mostly dropped, I am seeing tiny droplets of clear liquid on the branches - I'm assuming this is sap, but unsure if it indicates a bigger problem than the tree just having itself a Winter Moment and casting off its leaves. I haven't seen any evidence of parasites, at least not visible to the naked eye, and the Benjamina is unfazed.

Many thanks for any advice! I'm more of a conifer gal, generally, so I feel a little over my head here.

 

[JudyB]

Sounds like you have scale on the plant. You’ll have to get some spray to fight them and you’ll have to spray on a regular schedule as they do have a reoccurrence as new ones hatch out.

 

[takira]

Dangit, I suspected there was something Different this time. Do you have a recommended spray? I've used diluted lime sulfur to spray junipers with scale but don't know if that would be the best option here. I'm guessing it would also be a good idea to spray the asymptomatic Benjamina since they share a space?

 

[JudyB]

I’ve always used insecticidal soap. It’s not harsh does the trick, and more pleasant to use inside imagine…I would spray both plants.

 

[ShadyStump]

I was going to say aphids because they're notorious for leaving their honeydew behind them. It's rare, though, that they could do significant damage without being noticed.

For future reference, the issue of ficus or other tropicals dropping leaves when you change their environment is very common. They grow leaves custom to their environment, and when that changes they change out their leaves to adjust.
Also, ficus sap is always a white latex type fluid. This will help you tell when you suspect illness or infestation in the future.

 

[takira]

It's definitely not the white fluid I've seen when pruning the Benjamina - it's clear as water, though it gets a dull whitish appearance when dry. Still can't see any actual bugs, but I am seeing the start of the shiny material on the Benjamina's leaves (that's how it started on the willow-leaf), so they got both liberally sprayed with insecticidal soap today - I'm thinking maybe every 2 weeks for a couple of months or a couple of treatments past when all looks normal again?

Smelling nicer than lime sulfur is a low bar to clear but I'm happy to clear it.

Thanks for all the help. They love being outside in the summer but clearly picked up some hitchhikers along the way.

 

[JudyB]

I can see the scale in your photos. The oval shaped brown spots that sorta look like bark pieces are actually the scale insect. If you take a close look you will see them. Pick one off and squish it, you'll see that they are actually live pests. They just don't move the same as what we think insects do. I'm don't remember the timing on the scale life cycle, you should look it up and spray accordingly. Every two weeks sounds ok though.

 

[shohin_branches]

Yep, I agree with @JudyB , treat for scale asap! I often notice the sticky leaves before I see the scale. Rub as many as you can see off the branches and growth points with a q-tip dipped in rubbing alcohol and treat with a systemic based on label recommendations. Keep checking the tree every three days and removing any scale you see. You may need to do two or three rounds of systemic.

 

[takira]

I started with topical insecticidal soap for now, but will go back with a q-tip and alchohol this week - have done with pines in the past, though the bugs were a lot easier to see then. Sources seem to vary on duration of therapy, but there are also so many species it's hard to pin down a life cycle. I'm going to go with my old clinical saw of treating past resolution of outward signs and see how it goes.

 

[yashu]

Bonide makes an indoor systemic granular insecticide that’s very effective against scale and as a granular it has little to no odor. The active ingredient is imidacloprid which is a neonicotinoid so do your research and follow the directions.

 

[JudyB]

Rub as many as you can see off the branches and growth points with a q-tip dipped in rubbing alcohol and treat with a systemic based on label recommendations.

Yes, this! I haven't had scale for so long I forgot about the q-tip process... And it's oddly satisfying... but so is squishing them...