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Pome Fruit Disease Protection Starts Now

March 17, 2021
this agronomic image shows fire blight damage

fire blight damage

Apple and pear growers in the Pacific Northwest need to be on alert for fire blight and powdery mildew this spring. Heavy fire blight pressure for the last several years means inoculum is likely present and ready to infect trees when conditions become conducive. Powdery mildew often overwinters in buds with symptoms starting again during bloom. Here’s some helpful information about these 2 early-season diseases, along with management tips and guidelines.

Fire Blight

You can spot overwintering fire blight by looking for black, grey and violet cankers. If you cut these cankers away, the bark near the margin should demonstrate reddish flecking. These cankers will begin to ooze in the spring, which can coincide with bloom. Vectors carry the pathogen-filled ooze to open flowers and spread the infection throughout the area.

To preempt or combat a fire blight infection, implement a management program that includes Actigard® plant activator and traditional antibiotics. Actigard triggers the tree’s natural defense system, much like a vaccine.

Powdery Mildew

Powdery mildew is a fungal disease attacking both apples and pears. It can overwinter in infected buds, causing malformed shoots to emerge in the spring. Infected leaves appear to have a white or gray powder on them and will curl upward as they become covered in spores.

You will likely see the best treatment results from a fungicide application like Aprovia® fungicide between the pink and petal fall stages and through your cover sprays.

When started at the right times, fungicide applications – in combination with other management practices – can help improve orchard health year after year. Institute your management plans now to minimize disease problems this growing season and protect your pome fruits.

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