August 22 Nursery-Landscape Report

Environment Canada is calling for a warm, sunny weekend!  There is still a chance of rain today and tonight but tomorrow is expected to be mainly sunny with high’s in the mid-20’s.

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Magnolia Scale  crawlers are out! Crawlers are dark brown and very tiny but are visible to the naked eye.  They look like dark, oblong specks on this year’s twigs and on the scale shells themselves.  They will crawl slowly over these surfaces until they settle to feed on the twigs to complete the rest of their life cycle.


We are getting some reports of Orange-Tipped Oakworm moth (Anisota senatoria).  While these caterpillars are small they are very gregarious (feed together) and cause cause a lot of defoliation in a matter of days.  When they are young, they are very susceptible to most insecticides as long as the sprayer has good coverage.  B.t. (Bacillus thuringiensis) is an effective biological insecticide for this pest.  [Photos: Jason Lemay, LO Nursery Scout]

Plant Phenology indicators this week. 

A) North of 401 (700-900 GDD Base 10oC): Daucus carota (wild carrot, late bloom), Hydrangea arborescens ‘Grandiflora’ (late bloom to flowers starting to turn greenish), Sambucus canadensis (late bloom),  Sorbus acucuparia (yellow fruit)


Hydrangea paniculata ‘Grandiflora’ blooms turning from white to pink

B) Niagara (900-1100 GDD Base 10oC): Hibiscus syriacus (full bloom), Hydrangea paniculata ‘Grandiflora’ (late bloom to flowers starting to turn pink), Solidago canadensis (full bloom),  Sorbus acucuparia (orange fruit)

OMAFRA Publication 840, Crop Protection Guide for Nursery and Landscape Plants  can be found at:   It contains the crop pest recommendations for nursery and landscape plants that was previously found in publication 383.  Publication 840 is a .pdf file, accessible online and on cd. 

YelHeadSprSawflyCloseCheung Nursery-Landscape Insect Pest ID: Dave Cheung’s Common Pests of Nursery-Landscape database to help ID your problem pests. Check it out !!!

pub841-enCOVERcomp  OMAF publication 841, Guide to Nursery and Landscape Production and IPM, has now been posted to the website. It contains supporting information on crop production and maintenance in regards to nutrition, irrigation and integrated pest management (including plant phenology tables). To view the pdf, click here:



1) International Plant Propagator’s Society Eastern Region Annual Conference and Tours is coming up on September 17-20 in Niagara Falls this year.  Area tours of nurseries, greenhouses and botanical gardens will be taking place on September 17 and September 19.  Sign up for the entire conference or just the tours.  Please go to IPPS Eastern Region Meeting 2014.  Or click here for our promotional video.


2) OMAFRA Landscape Sprayer Workshop.  Application Technology Expert, Dr. Jason Deveau.  Jason is an expert in helping horticultural producers increase coverage and improve efficacy and this year, Jason is bringing his expertise to landscape and arboriculture. The OMAFRA Landscape Sprayer Workshop will be offered on Thursday September 25.

PLEASE NOTE: The Following Pesticide Recommendations are meant for Exception Uses (e.g. agriculture) under the Cosmetic Pesticide Ban unless the active ingredient is listed under Class 11 pesticides in Ontario Regulation 63/09, effective April 22, 2009.


Fall Webworm, it’s gonna be bad in SW Ontario!!!  Are you seeing webbing around the ends of branches on deciduous trees such as ash, birch and cherry?  Look inside the webbing and look for yellow, fuzzy caterpillars.  These are fall webworm caterpillars and we’ve been seeing them since June so they are going to be bad in some areas of southwestern Ontario.  Prune out nests and destroy them to prevent future colonies from infesting your trees.  Pole loppers are an awesome tool for managing fall webworm caterpillar nests!  Spraying is not effective.

Japanese beetle adults are flying and feeding on leaves of woody plants (Syringa, Tilia, Ulmus, Prunus, Rosa).  Look for metallic, coppery-green beetles with white turfts of hairs along the edge of their abdomens.

Japanese Beetle Mating Pair Japanese Beetle Feeding on Leaf

Adulticide insecticides for Japanese Beetle in the nursery include Sevin XLR and Thionex should be finishing up as late season damage is not as significant to tree health.  Funnel traps for JB are extremely good at attracting the adults.  Always place traps far AWAY (I mean away!) from susceptible host trees and shrubs (e.g. Rosa, Prunus, Tilia, Syringa, Ulmus etc.) and in JB hot spots, try to use floral lures (not pheromone lures).


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We have seen tons of powdery mildew on deciduous flowering shrubs (Amelanchier, Rosa, Physocarpus) and herbaceous perennials.  Monitor for white, powdery residue on the tops and bottoms of leaves.  Protect new foliage with fungicide applications [e.g. Switch, Milstop, Regalia (biofungicide), Tivano] but where the disease pressure is moderate to high, fungicides are not going to be effective.

Two-spotted spider mites (TSSM) are feeding  on several types of deciduous woody (e.g. Hydrangea) and herbaceous perennials. Look for chlorotic leaves with stippling, use your hand lens to see tiny, clear bodied mites with dark regions (may be faint black) on their backs.

<a href="/clm/species/teranychus_urticae"><em>Teranychus urticae</em></a> (Two-spotted Spider Mite).

These mites are small but the damage is significant so catch them early.  Miticides registered for this mite in the greenhouse include: DynoMite, Vendex, Kanemite, Floramite, Avid.  Apollo is registered in outdoor nursery crops to knock down the egg stage and newly hatched nymphs. (TSSM overwinter as adults in the debris layer on top of the soil).

There are lots of mites feeding on deciduous trees, Ulmus, Fagus, Quercus, Malus. Look for a “dirty” appearance to leaf undersides.  Usually damage this time of year is inconsequential for tree health.


Mites on Ulmus, leaf underside



Taxus or Fletcher Scale NYMPHS have settled on needles and twigs and are feeding.   As they become older, they are more difficult to kill with insecticides.  Several contact and systemic insecticides are registered for this pest in the nursery.  Fletcher scale go through a “September migration” and will move around the plant in a couple of weeks or so.  This may be a good opportunity to manage them with insecticides if you are seeing hot spots in your production area.

black vine weevil RumexBVW1Monitor for black vine weevil ADULTS in the FIELD and LANDSCAPE for Rhododendron, Taxus, Thuja and Euonymus.  It’s TOO EARLY for applications of nematodes in the field/landscape wait until about the second week of September to start nematode drenches of soil/container media.  Met52 (biological insecticide) can be used as a pre-plant incorporated application to effectively reduced larval populations in container production and can be used at any time of year that crops are being potted.

Cedar leaf miner (CLM) next generation larvae are starting to hatch and feed on tender new foliage.  A light sheering of tips in August should give good knockdown of CLM larvae.  Cygon is registered as a foliar application for CLM larvae in early August in the nursery.


Spruce Spider Mite Due to cool, wet weather, spruce spider mite populations are pretty high this month!!!  Monitor for nymphs and adults of spruce spider mite on conifers with a history of mite damage.  Spruce spider mite nymphs and adults are brown with black backs and found on new foliage this time of year.  Click HERE for a short video.  Miticides registered for SSM include Floramite and Kanemite.  Miticides may be required where pest pressure is moderate to heavy (container grown conifers with overhead irrigation).

  August is the month where American goldfinches are nesting.  You’ll be hearing a lot of their calls right about now.  Click here for a short video link to American Goldfinches.  Here’s another link to a video of a goldfinch harvesting fall webworm webbing to help line her nest (30 sec)!

Need a laugh?  One day I was looking for photos of larvae and I came across this video.  If you need a laugh, its 2 minutes well spent.  I lost it when I saw Larva Cocoon #2 Video.


About Jen Llewellyn

OMAFRA Nursery and Landscape Specialist @onnurserycrops
This entry was posted in Educational Opportunities, Insects, IPM, Weekly Nursery Landscape Report and tagged , , , , , , , , . Bookmark the permalink.

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