planetrj

First thought is location...
We always have to go back to basics before being hasty and spraying everything.
Let's talk about environment....

Bananas grow comfortably between 70-85 degrees, and do their very best in volcanic based soil.. but in the ground. A typical day in the tropics during the midsummer, begins with a sunny morning, dark and rainy midday (cloud cover), and often a sunny afternoon.

Given these parameters that Bananas do best in, there could be quite a few scenarios of why bananas do what they do in our sub-prime climates.

First, given that you're in the Southern Midwest, you're experiencing some super long, hot days and often the middle of the day, it's scorching hot. When a tender blade unrolls, it's subject to sunburn even after a few hours of scorching sun, especially when the temps go above 90 degrees and the sun beats down right on it. Also, if there are extreme days where it could be cloudy an entire day, then the next day, it's scorching hot with no cloud protection in the middle of the day.

One clue I noticed is the angular sections, which are often tell-tale of the exposed parts of the blade, especially at angles. The other clue is that it's very green close to the midrib, which indicates it's not internal, because the veins are not affected at the rib juncture. One last thing... If overfeeding, it can sometimes cause the leaf to roll out faster than it can build callous on the cuticle of the leaf, and if it gets exposed too soon, the cuticle will burn like this. Last is the soil. If there are too many soil salts built up and/or the pot is getting too hot (black pots often do this in scorching sun), root burn can happen which inhibits other parts of the plant from taking care of itself as well.

I think giving this a little bit of midday shade and maybe a cooler part of your yard (if it's in a container) everyday while it's the hottest time of the year is the best bet to keep this from happening. Also, keep in mind that when the temps get too hot, bananas will stop growing as well, so all is in your benefit to protect your baby.

Good Luck!!

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you will never have enough bananas ^_^