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Treating Pear Trees for Fire Blight

Updated: Jan 19

Burned Without a Flame

Wildfires get all the attention for devastating the biodiversity of California’s landscape.

Yet, in the background, fire blight stealthily infects and deals severe damage to Pear trees without all the paparazzi.


Wildfires or Fire Blight?

“Ah, early spring!” the groundhog, in all his wisdom, proclaimed.

Californians might get scorched by a wildfire caused by someone exploding a smoke bomb during a gender reveal party in our drought-ridden national forests, but at least we don’t have to shovel snow!

Though it isn’t wildfire season yet, the Pear tree in the backyard looks a little burnt. How?

Pear Tree


What is Fire Blight?

Bacterial leaf scorch, aka fire blight, is a fungal bacteria spread by all manners of pollinators and commonly infects Pear trees. Its characteristic burnt-like features are most noticeable when leaves have grown out.

Like serious burn wounds, fire blight can be overcome, but become fatal if left unattended.

Watch for signs of fire blight on a Pear tree, like scorched leaves, leaf wilt, dieback, and oozing cankers. Clumps of red or black on the leaves indicate fire blight may be present.  


House Call

Your favorite ISA Certified Arborist at Sims Tree Health Specialists made a house call and recommended the appropriate treatment to combat fire blight on the Pear tree.

Bloom season, typically from late January through March, is the ideal time to fight fire blight.

Little white buds or blooms indicate the ideal time to spray. Look for these signs in the springtime and schedule a service right away!


Trim! That! Tree!

To prevent further infection when the Pear tree isn’t in bloom, trim! that! tree!

Pollinators like birds, bees, and fleas (it rhymes) transfer the disease from one tree to another as they snuggle up between the leaves. Weather, like rain or wind, is also a culprit.   

Trim clumps of red or black leaves out, about 6-8 inches inward from the infected area. Pruning tools can also spread fire blight, so sanitize the blade with disinfecting wipes between each cut.

Trim after the blooms have fallen off when fire blight is present.


Be Fire Blight Aware

New leaves on a Pear tree can be likened to fresh wounds. The best time to prevent further spread of the infection is by “cleaning” the wound when it’s fresh.

New leaves form at full bloom (from late January through March), making it the best time to protect against fire blight.

When your Pear tree has reached stage 4 of its bloom cycle (see the graphic below), contact the office immediately to schedule an appointment to treat fire blight! The ideal time to treat is during stages 5 and 6.

Only you (and our ISA Certified Arborists at Sims Tree Health Specialists, Inc.) can prevent fire blight.


About Sims Tree Health Specialists, Inc. 


Sims Tree Health Specialists, Inc. is dedicated to the preservation, education, improved health, and safety of trees. Sims THS has provided California’s Urban Forests with premium healthcare since 1972. To learn more, visit our website:

Sims THS offers services with our ISA Certified Arborists in the following:


Diagnosis and Disease Management, Pest Suppression, Organic Solutions, Fruit Suppression, Drought Protection, and Arborist Assessment Reports and Preservation Plans.

In addition to providing quality tree health services, the Sims family is known for their educational pursuits. In 1996, they started the Sims Tree Learning Center (TLC), a 6-acre botanical garden and research facility sponsored by Sims Tree Health Specialists, Inc. The facility houses multiple types of gardens, including a cactus and succulent garden and one of the largest collections of Palms in the Inland Empire. Learn with us!

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