without doing any research... i dont see how a internal systemic can help with an external fire blight ...

it will also help.. if you specifically ID the EXACT problem ... if you have not done so already ....

read all labels.. and use chemicals or cures.. according to the labels ...

a good full service garden store.. will help greatly .. compared to bigboxstore ...

remove all fallen.. infected leaves .... and prepare to spray at the appropriate time of year..

i have about 10 crabs ... only the mature 20 year old... previously existing tree is phased by whatever it is ... i was told fire blight .. but refuse to expose the kids to spraying ... especially on a crab ....

if it werent shading my hosta.. i would be done with it.. and when the oak trees mature enough to cover the hosta.. this particular tree will be gone .... frankly .. its a losing battle ... IMHO ....

ken

If it's fire blight, it's a bacterial problem. Thus a fungicide won't work. In any event, when fireblight attacks, the affected leaves cling more often than drop.

Other problems affect crabapple. Among them the fungus disease scab. One of the symptoms is leaf drop. If that's the problem, the time to spray is at budbreak.

Thanks for the input. I now know it's not fire blight but most likely an apple scab. I'm planning on using Ortho garden disease control next spring at bud break. Thanks again.