Can anyone tell me what is wrong with this colocasia? What ever it is, it is spreading to other plants in the same grouping. I have tried cutting the ones down that have the problem. But that doesn't seem to stop it. Not fertilizer or pesticide-it is in 3 locations in yard and it is starting to develop in all 3 locations.
Barb, there is something colocasias get called Phytopthora leaf blight that starts out as little spots then spreads to cover the whole leaf. It is worse during warm, wet weather. You can spray with a fungicide(use a spreader sticker to make it stick to the leaves) Here is a link, but your spots don't look like the pictures they have http://www.extento.hawaii.edu/kbase/crop/Type/p_coloc.htm
I was looking to see if I could find any other diseases listed of colocasia, but there aren't that many that affect them. I was thinking your spots looked more like rust or something.
agristarts website says these diseases affect some colocasia. Alternaria, Botrytis Blight, Anthractnose, Phytophthora/Pythium Rot, Rhizoctonia Root and Stem Rot, and Xanthomonas Blight
Now I have no idea of the symptoms.
Anthractnose symptoms are spots! I should have remembered that. I get it on my foxgloves from time to time, especially in wet springs.
Barb, get out the Daconil. You will have to use some kind of spreader sticker(something like Safers Soap, just a squirt in the mixture) but try it on a leaf or two first to be sure it's not going to damage the leaves. The reason you will need a spreader-sticker is to make the fungicide stick to the leaf of the taro, otherwise, it just rolls off.
Some of mine are spotted like this,this year too.
Just noticed this on mine.
The white flies might be sucking the juice out of them Doc. The grasshoppers are really working everything right now, but they actually take the meat of the plant and don't just suck on them. I have no idea what it is, but I'm going out now and take a closer look.
Root, go get some Daconil. I found a few spots on one of my violet stem ones, I sprayed it! Tis the time of year for fungus to attack here with our cool, foggy mornings.
