I planted 16 Mohave Pyracantha (Firethorn) in ~ April 2015 parallel to the road line. So these are not fully grown. Within the last 2 weeks I noticed that one of them is turning all brown. Pics attached. The Pyras on either side are absolutely fine (all green), as are the other ones in line I am a beginner gardener, but from the pics I have seen, this does not look like fire blight (?). It may be too late to save this one, but I am concerned about losing more. Any suggestions?
Erwinia amylovora fireblight
You live and garden in the heart of fine horticultural activity. Collect the dead/brown plant, and submit it for examination by your local County Extension Service plant pathology division.
It looks like Fireblight to me, as well - but the plant pathology report can provide certainty.
In the event that you prune it out, which would be suggested, be sure that you are cleaning your pruning blades between cuts. This can be done with a 10 % bleach solution in water. With fireblight, we typically will prune 8 or more inches below the afflicted area or until the wood looks healthy and consistent- another reason to clean in between cuts as you may be assessing the rate of infection as you go. In your case, the pyracantha limbs will not allow this approach, so I would remove as much diseased material as possible. In addition, you could remove any grass and weeds that are growing around the plant. Grass is allelopathic and could be adding to the stress of the pyracantha, thus making it more susceptible to fireblight, eventhough it is already predisposed. When you remove the grass and weeds, this will allow you to take a look at the crown of the shrub to see if there is any presence of the pathogen and whether or not the entire shrub is a loss. Often times, in the case of fireblight(if that is what it is), it is only a matter of time until the plant fades entirely. Finally you may choose to apply a coarse mulch( arborist chips are good or a coarse wood chip mulch) around the shrub to cover the soil so that in the event of heavy rain or irrigation the soil will not splash up and potentially reinfect. Just keep in mind that you do not pile mulch up around the crown of the plant. I just pruned a firethorn last week, and man are those thorns unfriendly! Good luck
