Spring is Springing!

It was quite the wait wasn’t it? After witnessing one of the warmest February’s on record, March was quite a shock. But we seem to be on track now with a warming trend on the 7 day weather forecasts.  Night time low’s will be mostly above 0C.  Which means we will be accumulating some much needs heat units (Growing Degree Days) this week.

Where the Silver maples are in full bloom, red maples and pussy willow are beginning to bloom, we are between 1-25 GDD’s Base 10C.  Want to make this even easier?  Go to the Apple App store and download BugFinder on your iphone/ipad for free.


Cooley spruce gall and Eastern spruce gall adelgid overwintering females can be found on the undersides of last year’s twigs, next to the base of the needles.  Take a look at these tiny females with your hand lens.  If they are still blue-purple, that means they haven’t laid their eggs yet.  If you can’t see the blue-purple and they are covered in thick, white woolly wax that means egg-laying has started and pesticides will not be as effective.  Insecticides include Tristar, Sevin, Malathion and horticultural oil.  Be mindful that horticultural oil may remove the glaucus needle sheen on some conifers.

Manual IPM:


Gypsy moth egg masses are grey from overwintering but they can be detected on tree trunks, branches (e.g. Acer, Picea pungens, Quercus, Tilia etc.) as well as other wooden objects.  Scrape off egg masses, collect and destroy to prevent hatching of hundreds of caterpillars.


Eastern tent caterpillar eggs masses are grey and encircle twigs of last year’s growth.  They actually glisten in the sun so monitor for these on sunny days before leaf emergence.  Larvae will be hatching soon.  Prune out, collect and destroy eggs masses to prevent hundreds of caterpillars hatching and feeding on Prunus, Malus, Crataegus.


Look for cone-like structures hanging from the ends of branches at this time as signs of Bagworm.  This pest has been found in the Windsor and Coburg areas.  These “cones” are really overwintering structure that house the female and her hundreds of eggs.  Remove, collect and destroy cones to prevent significant defoliation on host plants (Gleditsia, Thuja, Picea).

VLB Egg mass

Viburnum leaf beetle egg masses can be found as raised grey-brown bumps, in rows along the UNDERSIDES of last years twigs.  Pick off the raised bumpy cap to see lots of yellow eggs underneath.  Prune out, collect and destroy egg masses to prevent widespread defoliation of our lovely flowering viburnums this spring.



About Jen Llewellyn

OMAFRA Nursery and Landscape Specialist @onnurserycrops
This entry was posted in IPM and tagged , . Bookmark the permalink.

1 Response to Spring is Springing!

  1. Pingback: Spring Has Sprung and So Have the Pests - Toronto Master Gardeners

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