This looks like black-spot on both of my feijoa trees (pineapple guava). I had an outbreak after the deep freeze in February. Eventually after trying Bonide Copper Fungicide (which didn't halt the advance of infection at all) I stripped both trees of 90% of there leaves, in late April, except for the canopy, which was not infected. This seemed to have stopped it.

The pattern are for the leaves to begin to show spots, rapidly turn yellow (within hours) and become easy to remove. I was removing on average 20-30 infected leaves each morning.

As of today, it seems to have come back, I'm assuming with the lowering of the temprature.

I live in Northwest Houston. The soil is slightly alkaline (I grow Paige mandarin trees, no issues). The trees are 4 and 5 years old. I use 1 inch thick cedar much in a donut (compared to the volcano method), though it's currently non-existent since I applied it in March. I use natural fertilizer. Both trees seem healthy besides the leaf spot, and grew on par with previous years. The smaller did not flower this year, due to the heavy loss of leaves, the other did, though no fruit due to no cross-pollenization. Except for a irrigation system watering 3 days a week, which I just turned back on on November 1st, we've seen little rain the passed few months

Crape myrtles near the feijoa trees in June developed spots on there leaves after several months of heavy rain (May-June). I removed all of the limbs (The previous owners kept cutting them back, so there ugly). Meanwhile other crapes in another part of the yard developed spots also, I didn't touch them, but never lost there leaves. I don't know if these could be contributing, since there both from the Myrtle family. This may have nothing to do with the feijoa trees infections, just giving all information I can.

So the questions are
I figure I'll need to strip the leaves off the feijoa's again to try to stop it, though as they get bigger, it this option won't be feasible.
Is this endemic? Meaning no matter what I do, it will keep on coming back during the spring and fall.
Is there anyway to halt the feijoa trees from becoming re-infected? Or is there something I might be doing to cause the infection.


Any help would be greatly appreciated

I think you are dealing with a complex issue here, so a few quick questions.

First: how do you apply the fertilizer and what do you use?
Second: before the freeze was the soil waterlogged or very moist?
Third: do all leaves become like that before dropping or have you noticed different spotting/discoloration patterns?
Fourth: was any mulch present during the freeze?

PS: your Crape myrtle plants most likely suffer from Cercospora leaf spot. You can use the copper fungicide you bought on those, just remember it needs to be reapplied every couple of weeks.