Help please: Black rotting spots on my Bodhi tree leaves!

It's also worth pointing out that you can continue to see increased leaf damage from spider mites even after you got rid of them. The parts of the leaves that they've damaged a lot will eventually die, but it takes time for all that damage to really show up so often you will have got rid of the mites but things still seem like they're getting worse instead of better because damage that had already been done is becoming more obvious as leaves turn brown, etc. That being said, I don't think the brown spots on your leaves are caused by spider mites, looks more like something cultural to me.

DEEP BREATH....

Thanks, everyone.

Pat

Hello everyone,

I am hoping that this post isn't misconstrued as obsessing over my tree, but today I have found what I believe to be fungus gnats on the foliage of my tree. I have done my research and have learned that these little pests are due to over-watering. I also have reviewed their life cycle and I also have learned that I need to let the soil dry out between waterings down to about 3 inches minimum. No problem. I have also read about yellow sticky card (AKA "Gnat Stix") control for the adults as well as pyrthroid based agents such as bifenthrin, cyfluthrin, permethrin, and lambdacyhalothrin. I also have read that Bacillus thuringiensissubsp. israelensis handles the larvae in the soil, although it doesn't sound like it is readily available in retail markets. I did read where "the systemic insecticide imidacloprid will also kill fungus gnat larvae when applied to the growing medium. This active ingredient is available in a number of houseplant insecticide formulations as granules, slow-release “spikes”, and in combination sprays with a pyrethroid-based insecticide".

What I haven't been able to uncover is any information as to their destructive payload. Is this possibly what is causing the white spots as shown below in the next post? Do the adults feed on the foliage? I have found two adults already on the foliage and I just looked at one leaf so far.

By the way, I switched to the following growing medium one week ago:

3 parts fir bark
1 part sphagnum peat
1 parts coarse perlite
2 parts fine Miracle Grow Perlite
Small amount of Black Kow brand composted manure.

I watered the new mix in and applied Miracle Grow 3-1-2 ratio fertilizer (24-8-16) as recommended by Al.

Does anyone know which steps (other than allowing the soil to dry out) work best for fungus gnat control? Preferably something I can get at one of the big box retail garden centers?

Would appreciate any and all suggestions other than to simply "stop obsessing" over my declining tree. That was a bit offensive as I came to this forum as a self-professed horticulture novice seeking professional help with a legitimate problem on the ONLY plant I own. This tree is important to me and to just wait and see what happens to it knowing that I have a persistent insect issue at the very least, is unwise in my opinion. I am a medical professional by trade and treating all possible causative factors of disease is in my blood, I suppose.

Again, thanks to everyone who takes the time to reply with genuine, sound advice.

Cheers,

Pat





This message was edited Jan 24, 2012 11:07 AM

White spots referenced above.

course sand on the top of the soil works best for me for fungus gnats.

Hey Trackinsand,

Thanks for replying. Can you be more specific? How much sand, type, etc. I know you say coarse sand, but where do you get it? Are we talking about a 1/2" deep pile covering all medium or what, specifically? I have the largest sandbox imaginable out my back door, but I am fairly sure beach sand is not what you are referring to. Remember, I am a total novice at growing plants as the evidence shows.

I have read further about it and some say cinnamon sprinkles mixed into the top 2" of the soil kills the fungus therefore taking away the gnat larvae food source, but one would think you'd have to water it in, which starts us back at problem one. Too much watering. Also heard where mosquito dunks in the watering can works also, but there
again, watering.

How does the sand work to control fungus gnats, do you know?

Thanks again.

Pat



This message was edited Jan 24, 2012 12:48 PM

This message was edited Jan 24, 2012 1:02 PM

i don't know why it works. i use builder's sand from the hardware store...about a quarter inch over all the soil. the best way to get rid of them though is to have soil that dries out quickly through the root system.
you say that you have re-potted it again so i assume you didn't like the Jungle Growth Flower/Vegi Mix. are you, perhaps, using too large a container for the plant? a plant can only take in so much moisture depending on the size of the root system. if your soil is staying soggy, the roots will rot before it ever dries out.

I believe that the pot is an appropriate size. The pot I am using is made of bamboo, 14" across at top, approx 9" across at bottom and 11" high.

The attached photo is of the root system when I switched form Miracle Grow to Jungle Growth. For reference, from where the roots start at the trunk to the bottom of what you see in the photo is approximately 8".

I switched from the Jungle Growth to a quasi version of Al's recommended soil mix. It's mostly large particle fir bark, and I watered about a week ago, and it drained like a sieve. I watered with a wick hanging out of the bottom of the pot for good measure and it drained very well I think. Just today it's starting to feel mostly dry down to about 4". (I bottomed out my index finger checking). The soil is hard to penetrate with my 3 in 1 meter due to the amount of coarse material in the soil medium, but with a little finagling and a bit of pressure, I managed to get the probes down to about 5" and the meter reads just barely above dry in the moist zone. I was planning to water tomorrow, with a couple of mosquito dunks dissolved in the water. The general consensus is that drying out the soil only makes them stop hatching, and when you re-water, they start hatching again, so I want to apply a definitive treatment. I have read where they do not cause foliage damage, but the larvae attack the roots and steal nutrition from the plant.

Thanks for the heads up about the sand. I will implement that step also.

I have a bad feeling though, that I will be starting out a new seed very soon. Last time I planted 23 seeds and was rewarded with 10 growers, but due to a move and lack of room to continue caring for 10, I gave all but 1 plant away to my neighbors at the time. In hindsight, I should have kept a few, but then again, I would likely have the same results. My tree is alive, but I simply cannot get ahead of the eight ball, it seems. It's gone from being root bound a bit, to spider mites and now, fungus gnats. Hate to think what's next. I realize Al is right about "Plant Time" and not being able to rush things, but I have attempted to get the culture conditions right based on the knowledge I have received and after a week, instead of it looking better, it looks worse and all new growth has stopped dead in its tracks. Perhaps it's just stressed. Very frustrating to want this beautiful tree for my den and to find I only have black thumbs.

Guess I will try the dunks in water and the sand tomorrow and see what happens. Perhaps the sand prevents the critters from coming up for air, and essentially smothers them and prevents other adults from burrowing down to deposit eggs?

Anyway, I appreciate your time, Trackinsand. Many thanks.

Pat






This message was edited Jan 24, 2012 5:37 PM

This message was edited Jan 24, 2012 5:39 PM

mosquito dunks are just a solidified Bt and to my knowledge, will not kill your gnats. there are several different strains of Bt used for different types of insects but not gnats.

i think your depth is ok on the pot but the width, imho, is way too wide. i would have used a pot half that size and gently coiled the long roots in a circle. in an ideal world, in the ground, yes, you would fan the roots out but in a pot is another story entirely. i'm just going by how i do things personally and what i've found works for me.

I've always heard that the strain of Bt in the mosquito dunks will work for gnat larvae too, although I've never tried it myself so can't vouch for that 100%.

Normally the biggest problem with fungus gnats is that the excess moisture that causes good conditions for them will hurt your plants--the larvae can do some damage to the roots but usually the excess water will have much more of a negative effect than what the gnats can do. I'm surprised that you'd have problems with fungus gnats though if you're using Al's mix since that corrects for the drainage issues that typically lead to gnats. Or did the gnats come before you switched to his mix?

I would also give the plant more time before you give up on it. Repotting is always a little stressful for the plant (similar to the transplant shock you get when you take something out of a pot and put it in the ground) so it'll take the plant more than a week to get back to being happy again. And if you did have spider mites, etc sometimes the damage from those things will take some time to manifest itself...leaves or parts of leaves that they damaged weeks ago will become more obvious as the leaf tissue dies & turns brown from damage that was done a while ago. Similar thing could happen as a result of cultural issues that you've subsequently fixed. But if you've gotten rid of the bugs and fixed the cultural issues then once the plant's settled in its new pot, it should eventually put out new growth and that new growth should be healthy.

i do stand corrected! http://www.entomology.wisc.edu/mbcn/fea207.html
that's what i love about dg...i'm always learning. it works as a drench.

Thank you Ecrane and Trackinsand, for your replies.

Ecrane: I would think the larvae was present before I switched to Al's soil mix, although I flushed the roots off well with the hose prior to re-planting into his mix. I cannot imagine his mix holding enough water, really. I could probably burn his soil mix as there is SO much bark and perlite in relation to peat. I picked up some Mosquito Dunks today and have crumbled 1/4 of one up (wearing gloves of course) into a 2 gallon watering can of water. The Mosquito Dunks material, even when crumbled up floats on the top of the water and moves across the water to clump, but the label states that it gradually disperses downward through the water column, which I guess is why they use square feet and not cubic feet. Anyway, I am giving it a couple of days for the BT to "fall" down through the water column I guess. The soil feels pretty dry, but the meter is still registering slightly dry at 4-5", and I see no signs of dehydration stress. As I said, I only used 1/4 of one dunk, due to the label stating to "use 1 dunk for up to 100 sq. feet of water, regardless of depth". I am quite possibly over-killing, but considering it says it is a biological mosquito control and it will reportedly not harm plant life, I dropped a "BT Daisy Cutter" of sorts to ensure that I get all of the larvae with one pop. It supposedly kills for up to 30 days.

By the way, thank you also for your kind recommendation to give the plant more time. I assure you, as frustrated as I get with not seeing it flourish despite doing everything "right" (now that I know mostly of what that is), I will never give up on this tree until it lays down and dies. I am the last to give up on a complex patient so this is also second nature. But thanks for the explanation about shock and the spider mite damage. I appreciate it very much and will keep your words in mind. :)

Also, should you guys ever need Mosquito Dunks, they are sold at Lowe's and will cost you a 10 spot for a package of 6 discs.

Ecrane, do you agree with Trackinsand that my pot is too wide? (No offense Trackinsand, just want a second opinion). Since I have switched to Al's mix, the soil doesn't hold water that long. I flooded the soil once I replanted until it poured out the bottom of the pot in a stream, and I used a wick also as Al recommended. Here it is, 1 week later and it definitely is on the dry side down to about 4". How much water SHOULD I give to a pot of this size on any given watering? Maybe Al can weigh in considering it's his mix, but I think I scared Al off. LOL

Anyway, many thanks to both of you for replying. I agree with you Trackinsand that this is a great place to learn. If I only had the time to sit and read ALL of the posts! Sadly, "winter" produces a lot more patient volumes due to snow birds being here, so I am working at the hospital about 60 hours per week on average.

Take care, all.

Until next time,

Pat

I'd have to see a picture of your plant in the pot to get a good sense of whether that pot is too big. Honestly though with Al's mix it won't retain water, so the size of the pot relative to the plant isn't as important. The reason why it's generally recommended to make sure your pot isn't too big for the plant is because most people use moisture-retentive bagged potting mixes, so if you have a lot more potting mix than you have roots then there's too much potting mix to hold water and not enough roots to absorb it quickly so the soil stays wet for too long. But with Al's mix that issue goes away so you could plant a tiny plant in a big pot and it won't matter because the potting mix doesn't retain excess water.

no offense taken, pat. all in all, you're pretty entertaining so i'm enjoying this thread and i love to throw in my 2 pennies even when i end up being wrong! lol
i do have to grudgingly say that ecrane proves me wrong more than i'd care to admit.... :-)

Well, if it weren't Al's mix being used in the container then I would have agreed on the pot size (although I still would want to see a picture to be sure--I can't really visualize how big this plant is from the pics that have been posted). We're all learning from each other here--that's one of the great things about this website. I knew next to nothing about gardening when I first signed up here years ago and I have to say I've learned more here than I have from any of the books/magazines I've read.

amen to that!!!

Hello again, everyone!

I wanted to give you all an update on my Bo tree, and show you a couple more photos.

I have good news and bad news.

Good news is, it is starting to grow new foliage again. The bad news is, the same white "spots" (insects?) that have plagued all of the other leaves in the past are again, affecting the new foliage. So, I am starting to question the "poor cultural conditions" theory now and I am suspecting I haven't eradicated the spider mites or whatever it is that is causing this. Unfortunately, I cannot get any closer shots with my camera without a tripod.

Please have a look at the close up photo of one of the new leaves and below in the next post, a photo of one of the older leaves that remain on the tree. Should I be removing these old badly affected leaves? I am afraid to take too many leaves off.

Does anyone know what is causing this recurrent problem?

Thanks,

Pat



This message was edited Feb 6, 2012 11:08 AM

Here's the photo of the older leaf. Should these be removed? I don't have but one new 3" leaf and a few 1/2" leaves that do not look similar to this. I fear if I remove the bulk of the foliage it will die. Does anyone know if this is true? If not, perhaps I should remove all of the foliage to hopefully rid whatever is causing this?

FYI, I have applied a BT drench (Mosquito Dunks) to the soil and have recently fertilized with the 3-1-2 Miracle Grow which I think is what spurred the leaf growth.

Please help me help my tree.

Thanks again,

Pat

are the white spots moving or are they possibly a characteristic of this plant? i wouldn't take any leaves off, especially the new growth. if you rub the leaf, what happens to the white spots?

Hey Trackinsand,

Thanks for the reply.

The white spots are not insects I do not believe. I think they might be damage spots from an insect however. The spots do not move and they cannot be rubbed off. I do not see any insects crawling on the leaves from what I can see with both the naked eye and examining enlarged macro photos of the leaves I have taken.

Yesterday I did a spray with castille soap just to be sure I wasn't missing anything and I also re drenched the pot with BT. Still using Al's growing medium and it appears to work better as far as drainage goes. I also water with a wick. I think I have the culture conditions correct, so I am at a loss for ideas.

I just cannot figure out what these white spots are the result of. They aren't characteristic of this species of ficus as far as I know. I do know that the near microscopic white spots on the bigger, more mature leaves turned into the yellow spots on the leaves you see in the last photo, which leads me to believe this is damage and not an insect. Any ideas what cultural condition could lead to this? I don't think it's edema simply because I have allowed the medium to dry pretty well before watering again.

Anyway, thanks for the reply. Seems you're the only one I have left. :)

Cheers,

Pat

truthfully, i wouldn't worry about it. if the plant is growing and producing new leaves, i'd take a "wait and see" approach...and i wouldn't constantly bombard it with feed or any kind of pesticide (including organic). mist it once every couple of weeks now and let it dry out more...just short of wilting. anyway, that's what i would do.

The white spots are normal inclusions called cystoliths, occurring in cells called lithocysts, normal parts of the plant's anatomy and common to the family Moraceae. If these structures are examined under a microscope, you'll see a little stalk or stem-like structure with a cluster of (CaCO3/calcium carbonate) crystals that look a little like a head of cauliflower on top of the stem. The chlorotic areas surrounding the structures are not normal and are due to one of the limiting cultural conditions discussed at length upthread.

Al

Once again Al, I thank you for your help.

The information about cystoliths is very helpful. I appreciate it very much. It opens up a whole new topic for me to research to become a better grower, so thank you.

Considering I am growing in the coarse soil mix and fertilizing with the 3-1-2 fertilizer as you have recommended, I am hopeful that the cystoliths will not turn yellow on the newly grown foliage. I have gained 7 new leaves in the last 10 days for a total of 15 leaves now, so things are certainly moving in the right direction I feel. None of the white spots on the new leaves have become chloriotic as yet, so i am hoping they remain this way.

If you were to suspect which cultural condition causes the chloriosis around the cystoliths, what would it be? I am refraining from watering the tree until the soil is mostly dry, and I use a Pur water filtration system to filter my city water prior to using. I would normally use reclaimed rain water, but it is the dry season here in Florida. I can purchase and use distilled water if you think chlorine may be to blame. I am still exclusively using the CFL bulb indoors from 8 am to 11 pm, unless it is a watering day and then I take the tree outside, into the sun for the day while the pot drains (using a wick). I am also considering the purchase of a Spectraboost full-cycle grow bulb.

If I may ask one other question, now that I have decent new foliage growth, would you recommend that I start removing damaged, older foliage slowly? I read where damaged foliage robs nutrients from the tree in an attempt to correct the damage and actually impairs new growth. Is this true?

Again, I appreciate your help.

Pat

"..... would you recommend that I start removing damaged, older foliage slowly? I read where damaged foliage robs nutrients from the tree in an attempt to correct the damage and actually impairs new growth. Is this true?"

Plants are shedding organisms. When plant parts are USING more energy than they producing, they will be walled off from the rest of the plant and shed. Unless the shedding occurs as a drought response, the process involves the plant removing/salvaging nutrients & other reusable bio-compounds from the organ it is shedding, and translocating them for use in other plant parts. A classic example of this would be when older/lower/interior foliage is shed due to a deficiency of N. The plant robs N from the foliage to be shed, and translocates the nutrient for use in NEW foliage BEFORE the older growth is shed.

If you have a stressed plant, it's better to leave even damaged leaves on the plant - for two reasons. One is, the damaged leaves are still contributing to the total volume of food the plant is making. Two is, if the plant recognizes via its chemical messaging system that the part (leaf) is using more energy than it is producing, it will shed the leaf of its own accord, deriving some benefit from the shedding process (removing nutrients & bio-compounds) it wouldn't get if you stepped in because you don't like how the compromised foliage looks. Later in summer, when you don't need to count leaves, you can snip them off with something closer to abandon because the plant will be making much more food than it can use.

I'm not going to guess any more at what might be causing the spots. You're making so many changes ant trying to implement soo many suggestions when you should be focusing on making sure cultural conditions are as close to perfect as you're able to make them, that it's simply an exercise in futility to try to pin anything down. Soil, light, temperature, watering habits, nutritional supplementation, and IPM are (IMO) all that are worth your concern.

I said before that things don't happen overnight. It will take until mid-late summer to get the tree turned around, and until next summer for it to be fully back on track. That's how trees work - they move slowly - and no matter how much you gnash your teeth, Mother Nature's program is going to prevail.

Al

Thanks for the reply, Al. Your information is much appreciated as always.

Pat