The Perfect Match Combating Fire Blight!

Spring is right around the corner and as history has shown, the season for fighting fire blight is upon us. I’ve had the opportunity to read many articles for pome fruit growers to prepare for a mighty season. However, there is perfect match to combating this devastating disease.

A typical shepherd’s crook is shown on this apple shoot with fire blight. (Photo: Kerik Cox)

Let me introduce you to Magna-Bon CS 2005, a copper sulfate pentahydrate in-solution formula that is OMRI-listed with systemic capabilities. By using less than an 1/16 lb per acre of metallic copper fighting fire blight, it’s more environmentally friendly than the competition.

Magna-Bon CS 2005 copper mixed with Marrone Bio Science Regalia has tremendous capabilities combating fire blight. Research performed at New York State Experimental Station inoculating 12-year-old ‘idared’ trees on B9 rootstock with a 90% infection rate labeled “Evaluation of Bactericide programs combating Fire Blight” by Kerik Cox, Cornell University. After 5 applications were made throughout the trials; 20% Bloom, 50% Bloom, 80% Bloom, Full Bloom/Petal Fall and during Terminal Shoot Growth, 1 pint of CS 2005 paired with 32 ounces of Regalia had a 92% control of the infection! Similar results in a simultaneous trial with 9.25% infection, the same mix of CS 2005 and Regalia had a 100% control!

Further research from an article published in American Fruit Grower, “This year was the perfect storm. After three years in a row with high fire blight infections inocula had built up and there was a lot of fire blight around. Warm wet conditions during bloom were ideal for fire blight infection. Unlike most years where fire blight hits late bloom conditions were right during full bloom, think millions more blooms. And we have more young susceptible varieties of apples planted. If you had fire blight in your apple orchard this year, it’s safe to say your approach to 2019 needs to change. Not only that, it’s safe to say that the pathogen is present in your orchard. Be ready to start with biologicals to protect during early bloom and antibiotics or coppers and biologicals for organic during full bloom to petal fall if conditions are right. You won’t have time to buy product so be ready.”

Tianna DuPont, Tree Fruit Extension Specialist with Washington State University

At silver tip, apply a big full rate of copper, too.

A fire blight canker exuding ooze with bacteria is shown on this apple branch. (Photo: Srdjan Acimovic)

“That will protect against any oozing cankers and any oozing fire blight that starts once the trees [start] pushing again,” Kerik Cox says.

Simply put, apply Magna-Bon CS 2005 and Marrone Bio Science Regalia this year to fight Fire Blight in your orchards.

If you have further questions, check out for application rates.

Click here for Information Sheet regarding Evaluation of Bactericide programs combating Fire Blight


“How to Recover from Fire Blight Devastation.” Edited by Christina Herrick, Growing Produce, American Fruit Grower, 24 Nov. 2018,