Whether or not you live in the desert Southwest, most people are familiar with the iconic Saguaro cactus.
To be honest, they are even more beautiful and impressive in person.
Unfortunately, like most plants, Saguaro cacti are susceptible to some diseases. The most prevalent is called ‘Bacterial necrosis’.
So, what are the signs of this disease?
Well at first, it can be a bit hard to spot unless you know what you are looking for.
I was revisiting with a client, helping them fine tune their garden when I took a look at their Saguaro.
The first noticeable signs are usually a circular, black lesion.
As the lesion grows, black ‘goo’ starts to leak downward on the Saguaro.
The liquid ‘goo’ has an awful odor, but depending on where the lesion is located, it may be too far to be detected during the early stages.
Saguaro bacterial necrosis is caused by the bacteria called Erwinia cacticida. It is spread by insects and/or soil. The bacteria enters through cracks or other wounds caused by rodents, insects, freeze damage or mechanical damage.
So, what can you do if you have Bacterial necrosis?
The vast majority of cases of Saguaro bacterial necrosis will result in the eventual death of the Saguaro, so treatment is needed.
For lesions that are rather small – (2 to 3 inches in diameter), scoop out the diseased tissue with a sharp knife. Cut into the healthy tissue as well, to ensure that you have removed all of the disease. As you cut, make sure the hole slopes downward so that any moisture will drain out easily and not collect on the bottom of the hole.
Then treat the area with a solution made up of a 10% bleach solution. That is it – let it heal on its own.
Unfortunately, if the infection has advanced further and the lesions are larger with quite a bit of ‘black goo’ then there is a good chance that the disease has progressed to a point that it is not treatable. Sadly, the only solution is to remove the Saguaro or the affected arm, which will prevent any damage from occurring since the disease weakens the Saguaro, causing it to fall. Bacterial necrosis can also be spread to neighboring Saguaro via insects as well, so removal is important.
For more information on Bacterial necrosis and how to recognize it and treatment, check out these links….