Ok, so after previously assuming that my Ice Cream had root rot (I had found what appeared to be a rotted root on my plant), I've decided to get a second opinion. I'm going to start the story from the beginning.
I got my Ice Cream in mid-July and the gardeners planted it in compost with a layer of gypsum underneath to help break down the layer of heavy clay below the topsoil. At first, I watered it diligently every day, never letting the soil dry out. Then, after a few healthy dark green leaves, I noticed something. The leaves were getting lighter in color, and the plant's growth was slowing down! This was by mid-August, when things started getting really hot (90+ degrees a day). The growth also slowed down by 50%, from making a leaf a week to making a leaf every week and a half. I thought that I was overwatering, so I decreased the frequency of watering my plant. I watered it by hand whenever the top of the soil was dry and let the sprinklers water it three times a week otherwise. Then, I just let the sprinklers water it. But the leaves kept getting lighter! At the end of August I fertilized it with 6-4-6 probiotic organic fertilizer. More recently, the characteristic pink edges on the newest leaves were not there and took a while to develop. I recently covered the sprinkler next to the plant so that the sprinkler doesn't overwater it. It's now getting a smaller amount of water from another nearby sprinkler. Now, the late summer heat is beginning to fade away, and it's still not speeding up it's growth or getting any healthier. Here are a list of my observations on the plant and its growth:
- Ever since a few weeks after planting, the leaves have been getting lighter and lighter. The older leaves remain green and healthy-looking.
- The lightest and most newly emerged leaves lack the pink edges characteristic of Ice Cream bananas, but the pink edges begin to develop after the leaf has fully emerged.
- On the most newly emerged leaves, the left side of the leaf is darker than the right side.
- There are a lot of ants around the base of the main p-stem.
- I found what appeared to be a rotted root. The same root was healthy just the day before.
- The plant is in the process of making a new pup, but it's taking forever to emerge out of the ground (it's been over a week and a half since I first discovered it sprouting from the main corm). Since I first discovered the new pup forming, it hasn't even grown up 2 inches.
- There is a very large trail of ants on the path next to the plant (it's ant season here). Over the past week the trail of ants has diminished.
- I checked the leaf sheaths for aphids, and found none.
- A few weeks ago, I saw a large root that looked perfectly healthy.
- The plant gets around eight and a half hours of full to near-full sun a day (from around 7:00 in the morning to 3:30 in the afternoon).
- The plant is planted next to a wall to help protect it from the wind.
- Other than the lighter leaves and slow growth, the plant appears to be perfectly healthy. The newer leaves are progressively getting bigger.
- There are lots of ants in the soil around the plant.
- The soil at least an inch under is constantly moist. The compost does not appear to drain well.
- The plant is planted at the top of a slope.
- There is a shrub growing close to the banana plant.
- I've found ants climbing on the petioles and leaves.
Here are my prime suspects for what is wrong with my plant:
Root rot: I have been suspecting root rot for a long time, and I recently found a root that appeared to be rotted (it was brown, slightly mushy, and when I pulled it off the inner part of the root didn't come off and it was slimy). Although, a few weeks earlier, I found a large root coming from the corm that was nice and healthy.
Masked chafer grubs: These grubs are the larvae of the masked chafer beetle (also known as a June bug). They feed on the roots of plants, particularly grass and shrubs. They can be very damaging to lawns. Damage peaks in late summer to early fall. Perhaps these are what are damaging my plant, and maybe the ants are very interested in them for some reason? Has anybody had problems with them feeding on banana plant roots in the past?
Heat stress: I know that too much heat can have bad effects on banana plants, but can it really turn their leaves lighter like this? And the symptoms don't seem to be wearing off as things are cooling down now. Plus, Ice Cream banana plants are pretty drought tolerant, so I'm not sure if this is the cause.
Here are a few pictures of my plant:
Here is my actual plant. Notice that the newer leaves are lighter in color. This picture is actually pretty out of date, it was taken almost a month ago. My plant has gotten a bit bigger since then.
I'm pretty sure this root is rotted. I had found it near the soil surface just the day before when I was checking on my plant, and it seemed to be healthy and new growth.
Here's a leaf just after it emerged. It's very light in color compared to the older leaves, and is lacking the pink edges characteristic of Ice Cream bananas. The left side is also slightly darker than the right side. After the leaf became more developed, it darkened slightly and the edges started to turn pink.
Here's a picture where it is easy to see the difference between the newer and older leaves.
I need to cure my plant of whatever is ailing it ASAP because winter is coming, and I don't want it to die during the winter! Can somebody please help me get to the bottom of this mystery?