Avocado tree pest issues

[Grant Simington]

Hello,

I bought an avocado tree last summer that was healthy and thriving all summer and fall, but as I live in Portland, OR area I brought it inside in late fall to keep it from freezing. Over winter it developed a bug problem and I tried multiple ways of getting rid of them, including manually killing/removing the bugs, neem oil, and diluted dish soap (a friend recommended this to me). Nothing got rid of the bugs until I was able to move the tree back outside 2 or 3 weeks ago.

First, does anyone know what the bugs might have been? The were very small and black and liked to live on the underside of the leaves, particularly the new growth. Everything I've read about avocado tree pests says that neem oil fix them, but these resisted a bottle of 0.5% neem oil spray all winter long. Any ideas?

Second, the tree is now completely leafless, and what new growth there is appears to be being sunburnt, which I've read is a problem with young avocado trees. I don't know if the bugs are still around, but I'm worried that with no leaves, the tree may be too exposed to the sun and die that way. The tree is about 4 feet tall and in a nice, large pot. The stem (trunk) is about half an inch wide at the widest point and is green almost all the way down to the soil. I water it infrequently and try to get it as much light as possible, but I'm now worried about the sunlight being too harsh for it. Additionally, I haven't fertilized it since replanting it last fall. Its possible that any of those are the reasons for the tree failing, but it consistently sprouts new growth, only for it to die and fall off, so I'm assuming it's the bugs.

I don't have a picture at the moment, but I can get one if necessary. Any help that anyone could give would be fantastic!

Thanks!

 

[Chuck]

Neem is good for some insects and basically useless on others. It is best used on egg laying insects. The best organic insecticide IMO is a spinosad based insecticide which kills by ingestion and contact.
Did the leaves brown, curl and fall off? What did the leaves do exactly? A closeup picture of the new growth will help I hope.

 

[Grant Simington]

They did brown and curl, especially the new ones. Some of the larger, more established leaves did less curling but browned. I'll snap a picture or two in about an hour when I get home and check out spinosad to see if it helps my issue.

 

[Chuck]

They did brown and curl, especially the new ones. Some of the larger, more established leaves did less curling but browned. I'll snap a picture or two in about an hour when I get home and check out spinosad to see if it helps my issue.

And if any of those bugs are still around a picture of them would be great.

 

[Grant Simington]

Unfortunately (or fortunately) the bugs don't seem to be around anymore. here are the pics.

 

[Chuck]

I don't know for sure what the problem is but it looks like a root burn or a salt buildup problem from synthetic fertilizers. Not knowing exactly what is going on here is what I would do. Start over. Remove the tree from the pot and change out all of the soil. Either sterilize the pot or get another. Repot with new soil. After repotting get a product called SuperThrive and follow its user directions. Use only organic fertilizers AFTER the tree re-leafs.

Avacados need sunlight and being inside for months hasn't helped. Put it outside, out of direct all day sun. Morning sun would be fine. Harden off the tree slowly for a couple of weeks before setting out in full sun.

When you water, saturate the plant and don't water again until the soil is DRY, in that pot about 4 inches deep. This could also be a watering issue.

 

[Grant Simington]

I wanted to update this thread. I repotted the tree about a week ago with all new soil. I didn’t get the superthrive as suggested as I seemed to have missed that part of Chuck’s post.

Since then the tree has only been getting worse. The black area at the top of the trunk has doubled in size and the tree has only grown a few leaves, which are again infested with the same bugs I was experiencing indoors. I don’t think the problem can be the soil, as I repotted the plant with the same potting mix as I used last summer when the tree was healthy. I’ve never fertilized and I’m very careful not to overwater the tree. I’m from Southern California, and know just how little water it takes to keep these things alive. My worry is the bugs and/or disease that seems to have taken hold over the winter. I’ve attached pictures of the bugs and the area of the tree as it turns from bright green and healthy stem to black and shriveled top.

 

[Chuck]

I wanted to update this thread. I repotted the tree about a week ago with all new soil. I didn’t get the superthrive as suggested as I seemed to have missed that part of Chuck’s post.

Since then the tree has only been getting worse. The black area at the top of the trunk has doubled in size and the tree has only grown a few leaves, which are again infested with the same bugs I was experiencing indoors. I don’t think the problem can be the soil, as I repotted the plant with the same potting mix as I used last summer when the tree was healthy. I’ve never fertilized and I’m very careful not to overwater the tree. I’m from Southern California, and know just how little water it takes to keep these things alive. My worry is the bugs and/or disease that seems to have taken hold over the winter. I’ve attached pictures of the bugs and the area of the tree as it turns from bright green and healthy stem to black and shriveled top.

Those insects are aphids. The top part of the tree is dead. Cut the dead part away, kill the aphids and use SuperThrive. It's a guess whether SuperThrive will stop the decay but it's the only thing I know of that can stop it.