Hello Louis,
I would also guess, that your prickly pear cactus is suffering from some kind of physiological disorder, i.e. sun damage or perhaps drought stress.
However, having said that, a cactus will also start to show these symptoms, if the root has rotted and the bacteria is moving up the stem.
To be on the safe side, I would cut some of the best upper pads off, let them callous over and then plant them in a different location or a pot.
That way you will at least save the plant. Then I would take a look at the root system of your Opuntia, in order to see, if that is the reason of the upper growth looking the way it does. Prickly pears are generally very tough plants and will grow quickly. However, I have successfully killed a few of them myself,
![Embarassed :oops:](./images/smilies/icon_redface.gif)
including a beaver tail opuntia (O. basilaris). Some of my plants - and I do have 22 kinds of Opuntias - do suffer from the harsh climate (abundant sunshine with 100 degrees F and above) and will look a little bleached or purplish around the areoles after the frost during the winter months. Once the conditions change, most of the pads will turn a normal green again.
One thing I can say: I do not see any insects (at least the larger kinds) on your plants and I do not recognize any definite disease symptoms.
You can go ahead and click on the tab named "Pests and Disease" at the top of this page. Perhaps that will also give you an idea, what the problem with your cactus could be. At least, then you can most likely rule out those possible causes.
I am sorry, I cannot be more specific. A picture is good and oftentimes helpful, but sometimes it takes some close-up "detective work" to solve the case of a "sick" cactus.
Harald