Category Archives: Diseases

Hot, Humid Days are Here

Gymnosporangium rusts, like this Cedar-Apple Rust gall, are finally sporulating! These rusts overwinter on perennial gall on the evergreen Juniperus hosts. In the spring, they are stimulated to sporulate during warm, wet periods. We’ve had the heat, but its been … Continue reading

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Protect Evergreens Starting As New Growth Emerges

Monitor for needlecast and blight diseases on older foliage where new foliage is emerging on Austrian pine and Colorado spruce.

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Those Precocious Blooms of April!

outher       Norway maple (Acer platanoides and its cultivars) are just starting to bloom in the GTA, making this one of the earliest blooms for trees since 2012! Continue reading

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Crabapple Disease Management Begins Soon!

Fireblight (apple, pear, see above) and Apple Scab (apple) diseases are normally reproducing and spreading this time of year.  This week we are more concerned about Apple Scab.  The cool weather has really reduced the activity of fireblight bacteria and so the risk of fireblight is looking low again this week.    

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Late Spring IPM for Landscape and Nursery

Foliar diseases such as Anthracnose can be seen on deciduous trees in the landscape, especially on maple, ash and oak.  The fungus infects leaf tissue as it is emerging, especially during cool, wet springs.  Fungal infection causes some distortion and … Continue reading

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The Monday Report: May 25, 2020

We can still see the remains of low temperature injury from a couple of weeks ago.  Not to worry, the next set of leaves will cover up the desiccated leaves and stems.

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Protect Evergreens Starting As New Growth Emerges

Monitor for needlecast and blight diseases on older foliage where new foliage is emerging on PINE and SPRUCE.

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Here Comes the Warmer Weather!

  What a treat! Several of our sugar maples are blooming this year all over southern Ontario, from Barrie to Niagara, these native beauties are gracing our landscapes with blooms.  Its been 5 years since sugar maples were blooming like this. The cooler weather continues!  Climatologists are predicting that our daytime temperatures will stay moderate until about the […]

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Continue to Protect Apple, Crabapple and Pear from Fireblight and Apple Scab

Fireblight (apple, pear, see above) and Apple Scab (apple) diseases are normally reproducing and spreading this time of year.  This week we are more concerned about Apple Scab.  The cool weather has really reduced the activity of fireblight bacteria and so the risk of fireblight is looking low again this week.    

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Fruit Tree Disease Management Begins at Green Tip

Fireblight (apple, pear, see above) and Apple Scab (apple) diseases are normally reproducing and spreading this time of year.  This week we are more concerned about Apple Scab.  The cool weather has really reduced the activity of fireblight bacteria and so the risk of fireblight is looking low again this week.    

Continue reading

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