POP TIPS: fire blight & black knot alert!

[Phil Forsyth]

Philly Orchardists,

We seem to be seeing high levels of fire blight on apples and pears in the city this spring and the sooner the better to take action to control this aggressive orchard disease! 

This edition of POP TIPS highlights two common fruit tree diseases that require immediate pruning to prevent further spread and damage:  

1.  Fire Blight is a very common and serious bacterial disease that affects pome fruits (apple, pear, Asian pear, quince, medlar, hawthorn and serviceberry).  We've seen many trees with some fire blight this season- untreated, these infections can kill trees by the end of the year if not pruned out! 

  

Typical fire blight damage appears as if the tips of branches have been singed by fire, often bending over to form a 'shepherd's crook'.  It can also affect fruit, which appear black and shriveled. 

If you identify Fire Blight in your orchard, please see our video on treating Fire blight on POP's youtube channel and our blog post on Fire blight for more information. 

2. Black Knot is a fungal disease common on plums and cherries and has also been noted in orchards this spring:   

Easily identifiable damage from black knot disease on cherries and plums! In the spring, it is a lighter tan/olive color.  

 

Black knot will continue to spread and cause additional damage if not removed.  For more information on preventing and treating it, see our full blog post on Black Knot here.  

For both Fire Blight and Black Knot, the first course of action is pruning 6 to 12 inches below any sign of infection.  Always sterilize your tools with rubbing alcohol, hydrogen peroxide, or a 10% bleach solution after every cut to prevent spreading the disease further! 

Phil Forsyth, Co-Executive Director

Philadelphia Orchard Project

www.phillyorchards.org

215-724-1247

Pronouns: he/him

"66 community orchards, 1578 fruit trees, and growing!"