Houseplants forum: 2 kinds of insect pests, along with possible other underlying problems, help!

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CLay04
Feb 18, 2018 1:11 PM CST
Before starting up this message I have a Sugar apple tree (Annona squamosa) growing inside. I have a dish under the pot that I keep it in, and drainage holes in the bottom of the pot. I keep it under 4 fluorescent bulbs and it also sits next to a window which gets maybe 2-3 hours of sun a day (which is why I have the fluorescent bulbs) as this tree is tropical I knew it would be no easy task growing it indoors, especially living where I do (hot summers, but cold winters). The tree is almost 2 years old now, and before the past few weeks was growing great. I keep an eye on the humidity and temperature in my house, never letting the temp drop below 65 and the humidity never dropping below 30% (for long periods of time) during winter.

With all that said I have started to encounter problems; my first was fungus gnats, I knew that sugar apples were decently desiccation tolerant so I let the soil dry for nearly a month, knocked most of them out, watered it after and saw new growth occur, I now use yellow sticky traps to keep them at bay along with a top dressing for the soil known as gnat knix.
The next problem I encountered was white flies, They started small and attacked a decent number of leaves. I killed most of them simply by scraping them off of the leaves (they are so fragile they would usually get smashed on my hand as I scraped them off). I then used safer brand insecticide to kill off any left larva or eggs that were not as visible as the actual white flies themselves.
These are the only two "pests" I have seen on the plant, every now and then I will see a dead centipede on the top of my soil, or after I water sometimes a redworm (skinny red worms though) will crawl up to the surface of the soil/ gnat knix. But as far as I know redworms and centipedes are beneficial to the soil media and also the plant.
So now the issues I have been having I had a lot of yellowing leafs have had a few actually drop. Some of the new growth has actually fallen off (not all). New leafs are coming in with deformed shape, brown tips a hole or two in them... ect... I am attaching pictures of the plant to be helpful, I know this is an uncommon tree, especially to be grown indoors, however it is my favorite fruit, and I am unable to buy that fruit where I live. Also the tree needs to be staked up because I let it grow sideways and forgot to raise the light for a while.

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Name: Will Creed
NYC
Professional indoor plant consultan
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WillC
Feb 18, 2018 1:35 PM CST
Indeed, this is an uncommon plant to grow indoors, primarily because it is difficult to provide adequate light and also it does best in a very humid environment.

Outdoor light, even in light shade, is much more intense than direct indoor sunlight even when supplemented with fluorescent lights. There is no substitute for light and that is the primary reason your Annona is now developing yellow leaves. Another problem is the very large pot that is retaining moisture for too long and is probably suffocating the roots. The presence of the fungus gnats is an indication of that. It is the damaged roots that are causing the deformed new leaf growth.

I realize that this is more explanation than the solution. That's because I don't know that there is a solution unless you can provide much more light year round, such as in a greenhouse or solarium. You could try pruning it back and watering more judiciously, but that will not solve the long-term problem of inadequate light.
Will Creed
Horticultural Help, NYC
www.HorticulturalHelp.com
I now have a book available on indoor plant care

CLay04
Feb 18, 2018 1:46 PM CST
Yes I have cut back on watering quite a bit, as I know it likes looser soil I mixed in perlite and some other things to loosen the soil, The fungus gnats are mostly gone. In the summer I am able to take it outside as the temperature here gets up around 80-100 in the summer. My house over the summer stays about 80 degrees and very high humidity, bad insulation and only window units in an old house help that.
Also in the summer and into the fall before the fungus gnats and white flies hit the tree seemed to be growing fine. once winter came the pests followed the warmth inside, along with overall dropping temps and humidity I was considering a combination of these things could be doing this.
As far as the lighting goes I work in a lab studying tropical plants (we have a greenhouse, but I would not want to introduce pests to it) and when we bring plants into the lab from the greenhouse to run studies with them we use either LED or fluorescent in timed 12 hour light cycles and the plants seem to be fine with it even when kept indoors, I may add an LED or two around my set up until summer rolls back around.

CLay04
Feb 18, 2018 2:12 PM CST
When I say high humidity, my house stays about 78-81 degrees in the summer and about 70-80% humidity.If I am able to take it outside in the summer and completely get rid of the fungus gnats and whiteflies I could take it to my greenhouse in the winter, Would I be able to keep it at home over the summer so that I can hand pollinate it, or do you think I would need to keep it in a greenhouse year long? I am in zone 6b I believe.
Name: Sally
central Maryland
Seriously addicted to kettle chips.
Charter ATP Member Native Plants and Wildflowers Region: Mid-Atlantic Composter Region: Maryland Birds
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sallyg
Feb 19, 2018 7:54 AM CST
I think it can limp along till May when it will be warm enough to go outside. Daylight is slowly getting better now.
The original soil is potting mix, right? You have loosened some, but down lower it still may be heavy, meaning the roots might still be struggling in,or not able to use, the lower part. That's only IF the original soil really had problems. Since you mentioned worms I have to ask if you used garden soil.
Be careful about taking it to the lab though, don't want you to get in big trouble. I don't see pests when I bring my plants in, but they are often there.
..come into the peace of wild things..-Wendell Berry
Life is a buffet (anon)
Name: Will Creed
NYC
Professional indoor plant consultan
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WillC
Feb 19, 2018 9:06 AM CST
Fungus gnats are rarely a problem when plants are outside, in part because they fly off and are not noticed as they are in an enclosed space. There is also better air circulation outside. If the soil is staying too moist, the gnat larvae will be there year round.

Even with a very porous potting mix, the soil can stay too damp for too long if the plant is in an oversized pot, as yours is.

Many plants thrive under just fluorescent lights alone. Annona is not one of them unless you have special high-intensity lamps that are kept close to the plants and are in the appropriate color range. Keeping it in your greenhouse is probably a better option as long as it doesn't get too cold there. You can move it outside in the warmer months, but it will need time to acclimate to the increased intensity of outdoor sunlight.

Another alternative is to keep it in your home in winter, but cut it back very sharply before moving it outside in the late spring.
Will Creed
Horticultural Help, NYC
www.HorticulturalHelp.com
I now have a book available on indoor plant care

CLay04
Feb 19, 2018 11:52 AM CST
I actually did not use garden soil, I found a potting mix for planting trees which was fairly "breatheable" I later on mixed in perlite and some other things. I know a lot of the yellowing leafs are due to the white flies. As of right now I am planning to re-pot it to a smaller pot once in the summer months when it is warmer. Also I have shady areas around my house, so when spring/ summer comes I will be sure to start it off in the shady areas keeping it out of direct sunlight. I bought the tree from a greenhouse, I am assuming the centipedes and red worms that are in the soil traveled to my pot from the green house. What size pot would you recommend for this size/ age of tree.
Also if the tree does not start to get better I may consider moving it to the greenhouse. we work with tropical mosses so It stays warm and humid enough for me to keep it there if needed. However, I would prefer keeping it at home if I can make it work.
Name: Will Creed
NYC
Professional indoor plant consultan
Image
WillC
Feb 19, 2018 1:57 PM CST
The pot size should be just large enough to accommodate the roots snugly along with just enough potting mix to cover the roots. When properly potted, a thorough weekly watering is usually required. Never put a plant into a large pot in anticipation of its roots growing much larger.
Will Creed
Horticultural Help, NYC
www.HorticulturalHelp.com
I now have a book available on indoor plant care

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