Its Time for Cultural Management of Fall Cankerworm

Homeowners and horticulturalists alike will remember being inundated with tiny, green loopers feeding voraciously on many of our shade trees this past spring (Acer, Betula, Celtis, Fagus, Malus, Quercus, Tilia, Ulmus).  These were the larvae or caterpillar stage of the Fall Cankerworm (Alsophila pometaria).

<a href="/clm/species/alsophila_pometaria"><em>Alsophila pometaria</em></a> (Fall Cankerworm) larva.

Larvae are light green with thin longitudinal white stripes down their bodies and 3 pairs of prolegs at the end of their abodomen (although, the first pair is much smaller and you might miss seeing it).  Larvae grow to 2.5 cm long. There is also a black-green race.  (Photo: Dave Cheung).  Continue reading

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Spruce Spider Mites are Loving This Weather!

spruce-spider-mite-black-kt-2          Monitor for adults and eggs of spruce spider mite (Oligonychus ununguis) on conifers with a history of mite damage (Abies, Picea, Thuja).  These are COOL season mites that will feed on current seasons’s foliage well into the fall.  In fact, fall is a pretty important season for this mite species as they can feed way up until the end of Continue reading

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Get Ready for Fall Dormant Oil Applications

Gray Treefrog

The Grey Treefrog is a carnelian, it can change colour from green to grey, depending on their environment. (Photo: Joe Crowley)

Today marks the first day of Autumn.  And with it another interesting calendar event, the Autumn Equinox.  Like the Spring Equinox (March 21), the Autumn Equinox marks a unique period of time where the length of daylight and night time hours are pretty much equal.  So as you can imagine, the wildlife can get a little confused this time of year.  If you spend time outdoors you might notice the odd mating song of birds and frogs.  I have heard a lot of male Grey Tree Frogs singing in the last week or so.  How cool is that?  Continue reading

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Introduced Beech Scale Nymphs on American Beech


Close up of colonies of beech scale (Chris Malumphy, The Food and Environment Research Agency,

Introduced Beech scale (Cryptococcus fagisugae) is easier to see this time of year on our native American beech (Fagus grandifolia).  That’s because of the white waxy coverings the females produce to protect their eggs.  Look for Continue reading

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Unwanted Herbivores in the Nursery and Landscape


The adult meadow vole.  How can something so “cute” be so bad?  (Image: John White)

Last fall and winter was one that I’ll always remember.  The rodent population went NUTS and we had a lot of feeding damage on nursery and landscape plants.  This year, we haven’t seen as many rodents around.  Low precipitation levels and tough growing conditions have diminished food sources that would support large populations of rodents.  Natural predators seem to be on the rise again. Mice and voles travel in tunnels under the snow or under the cover of fall foliage and feed on the bark and phloem of several tree and shrub species.  The longer the winter, the more damage they can do and so far, Continue reading

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Good News! Beneficial Insects Found on Magnolia.


So I started getting some queries about a new mealybug found on Magnolias in the landscape.  You can imagine my despair, the poor magnolias have their fair share of sucking insect pest problems with the glut of Magnolia scale we are finding on our beloved specimens. Continue reading

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Magnolia Scale, the plague of the landscape


Magnolia Scale is just rampant this year again.  And to make matters worse, there seems to be two developmental groups of them, a smaller subset about 3 weeks behind the older ones (see photo above).  This means a second set of insecticide applications (e.g. insecticidal soap, hort oil, or traditional insecticides) if you are trying to manage this pest.  Magnolia scale females will be laying eggs soon, in the next week or so.


Pick off Magnolia scale female to uncover newly hatched crawlers hiding underneath (early August, J. Llewellyn)

Pick off scales to reveal dark grey eggs and crawlers (eggs with legs) underneath. A week or so later, you will see eggs are hatching into crawlers.  But many crawlers will hide underneath the female scales for days before they venture out, meaning they are protected from insecticide applications.

CroppedMagScaleCrawlersUnderShellComp The crawlers will gradually emerge out from under the dead female mothers. Contact insecticides (traditional insecticides, insecticidal soap, horticultural oil) can be used to manage crawlers once they emerge and start feeding on twigs (mid-late August).

If you miss the Magnolia scale crawlers, don’t worry.  They overwinter as tiny, dark grey nymphs on the undersides of twigs.  It is advisable to go in with a fall dormant oil sprays (with emphasis on contacting undersides of twigs) to significantly reduce the population in October.  Many horticulturalists say that fall dormant oil applications are the BEST way to manage this pest issue.  But your clients may have other ideas.

Continue reading

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