July 2 Nursery-Landscape Report

Environment Canada is calling for showers and thunderstorms today, the chance of showers on Thursday and then clear and sunny by Friday.  Much cooler temperatures are on their way for Thursday afternoon.

Plant Phenology indicators this week.  A) North of 401 (400-500 GDD Base 10oC): Catalpa speciosa (full bloom), Syringa reticulata (late bloom),  Hydrangea arborescens ‘Grandiflora’ (early bloom)

B) Niagara  500-700 GDD Base 10oC) : Catalpa speciosa (late bloom), Syringa reticulata (late bloom), Sambucus canadensis (early bloom), Hydrangea arborescens ‘Grandiflora’ (early bloom), Daucus carota (full bloom), Yucca filamentosa (full bloom)

image0001 Are you seeing white cocoons inside webbing all over the place?  It’s probably the cocoon of the Eastern Tent Caterpillar.  They are inside completing the incredible process of “metamorphosis” where they turn from an ugly caterpillar to….a dull brown hairy moth (sorry).


Eastern tent caterpillar adult moth having a bad hair day (Michigan State U.)


1) GrowersNursery Growers Research Auction.  Wednesday, July 16 at Winkelmolen NurseriesLandscape Ontario’s Growers Group invites you to its annual fundraising auction
No admission fee or RSVP required. Bid on top quality plant material and tour the production farm while helping raise funds for industry research and scholarships.  All winning bidders will be entered into a draw for a special prize. Enjoy lunch, network with peers and bid on fantastic items – something for everyone!


  • Farm Tours:  10:00 a.m. – 11:30 a.m.
  • Lunch and Refreshments:  11:45 a.m. – 12:45 p.m.
  • Live Auction: 1:00 p.m. – 4:00 p.m.

2) Landscapers and Arborists: OMAF Sprayer Coverage and Calibration Workshop”Friday, July 18. 

  Come to the Landscape Ontario office in Milton to learn from OMAF’s own 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 professionals.  Jason will take you through sprayer calibration for landscape equipment and show you how to assess and improve coverage.  This 3-hour HANDS-ON workshop is perfect for landscapers and arborists that apply pesticides and fertilizers.

To register, click here: OMAFSprayWkshpRegJuly 18

or contact Kathleen at LO at kathleenp@landscapeontario.com


Japanese beetle adults have been sited in the Hamilton region.  Adults are just starting to emerge in southern Ontario.  European chafer adults are out mating and feeding on broadleaf trees.  Now is the time for preventative applications of insecticides on nursery stock.

To help qualify for the Japanese beetle certification program, an application of Intercept 60WP on container stock or field stock should made between late-June to August 15 this year (JB adult flight period).  The cut-off period for Intercept applications to comply with the JB Certification program this year will be August 15.

Adult Black Vine Weevil black vine weevil

and Strawberry root weevils O_ovatusAdultDC

are emerging and starting to feed on various evergreen and deciduous hosts in field and container grown ornamentals.

Look for Strawberry root weevil adults in spruce, eastern white cedar and sometimes in juniper. SRW’s will chew notches in small twigs, girdling them and causing the shoots to turn brown.

SRWDamageOld SRWFlagging

Look for adult black vine weevils in yews, eastern white cedar and euonymus. BVW adults will chew notches in the margins of leaves.


The soil dwelling larval stage of these weevils is the most damaging life stage but is difficult to control in field soil.  Adults can be managed in nursery production with insecticides such as Actara, Scimitar SC, Sevin and Thionex.  Monitor for adults by placing out wet boards or burlap on the ground underneath the crop.  Monitor for weevils under the board/burlap during the day.  Alternatively you can shake the canopy onto a light coloured sheet and count adults that fall on the sheet.


image0001 image0006 We have seen more powdery mildew on deciduous flowering shrubs (Amelanchier, Rosa) 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 (bio)) where the history of disease pressure is moderate to high.


Our nursery scout saw fall webworm adults laying their eggs recently on the foliage of deciduous trees (cherry, ash, apple, birch etc.).  Fall webworm larvae form very strong webby tents on the ends of branches from where the feed inside on foliage.  Prune out fall webworm nests and destroy to reduce the next generation of adults.  There are several generations of fall webworm that cycle through the summer and become more numerous by August and September.

Peach tree borer (Synanthedon exitosa) adults are finishing flying and bark applied insecticides should be finishing up at this time. Look for cankered regions and chewed bark/wood in the lower stems of Prunus (Prunus x cistena) as a sign of larval damage.  These clear-wing moths resemble wasps. PeachTreeBorerAdultMale

Adult Peach tree borer moths are very much attracted to sticky wing traps that are baited with peach tree borer pheromones. Place pheromone traps out in early-mid June (approximately 390 GDD Base 10oC, ‘Red Prince’ Weigela in full bloom) and monitor for peak flight of adults.  You can expect peak egg hatch around 10-14 days later, if you are thinking of treating newly-hatched larvae.  The same ‘clearwing moth’ pheromones and traps can be used to monitor for Viburnum borer.  Viburnum borer chews the stem (at and below the soil line) and causes significant injury to container grown Viburnum.  Viburnum borer will be starting to emerge in container production at this time.  To purchase traps, try ordering from IPM suppliers such as www.greatlakesipm.com and www.naturalinsectcontrol.com.   Some growers are trying soil drench applications of beneficial nematodes, S.c., (Steinernema carpocapsae) after peak adult flight, as a biological way to suppress hatching larvae.  We found that bark applications of S.c. gave a significant reduction in # larvae in a field trial last year.

Emerald ash borer adults are still flying and feeding on ash leaves at this time. Look for adults casting shadows on leave in upper canopy on sunny days.

EAB adults casting shadows on leaves (Markham)

EAB adults casting shadows on leaves (Markham)

Injectable insecticides may be used to protect ash trees from new infestations of Emerald Ash Borer (Agrilus planipennis).  Trees must be actively transpiring in order to maximize insecticide uptake into the cambium.   Registered injectable insecticide products include: AceCap 97, Confidor 200 SL and Tree-Azin.  Check out the Management Strategy for Emerald Ash Borer and Bronze Birch Borer at:  http://www.omafra.gov.on.ca/english/crops/insects/eab-bbb-manage.htm.  Emerald ash borer adults start to emerge when the black locust (Robinia pseudoacacia) are blooming.

The regulated areas for Emerald Ash Borer in Ontario and Quebec can be found at:


Adult bronze birch borer beetles are finished laying eggs on the bark of susceptible birch (e.g. Betula pendula).  Symptoms of larval boring damage appear as branch tip death, branch death and death of the leader and progresses quite quickly.  Destroy pruned material to prevent emergence of beetles. Natural resistance to this pest can be enhanced through activities that improve plant health, such as light fertilizing (May, October), irrigating and removing any weeds and grasses that provide competition for the tree.  Betula pendula is most susceptible to this pest and should be avoided in areas of known BBB infestation.  Betula nigra and its selections have been shown to be quite tolerant to BBB attack.  Confidor injectable insecticide is labelled for bronze birch borer.


Potato leafhopper nymphs (no wings) (and white cast skin to the left)

Potato leafhoppers NYMPHS and ADULTS are feeding on woody nursery stock.   Monitor for potato leafhopper on nursery crops such as Acer (platanoides, saccharum), Quercus and Ostrya.  Adults will fly away quickly but nymphs are about 2 mm long and scuttle SIDEWAYS, rather quickly, across the leaf and to the other side (they don’t have wings). Susceptible crops are those that are flushing new leaves (leafhopper’s favourite food source).  Older, hardened off foliage is not usually as susceptible.  Leafhoppers (and aphids) suck plant sap from soft, expanding foliage and cause foliage and stems/petioles to wilt, turn brown/black (‘Hopper Burn”) and become stunted and malformed.


Older, hardened off foliage will become flecked from potato leafhopper feeding.  Monitor populations and treat the 1st generation NYMPHS with insecticides before damage becomes economically threatening.  Leafhoppers are also attracted to yellow sticky cards, for monitoring.  Registered insecticides include Tristar and Sevin XLR.

Aphids are quite numerous on herbaceous and woody ornamentals this year!  They do well in cool weather because leaves stay soft and easy to feed on.  Green peach aphid is one of the most common species and melon aphid and foxglove aphid are also quite common.  This year we are seeing large colonies of black bean aphid (Aphis fabae) on deciduous flowering shrubs and Euonymus.  Aphids are sucking insects that cause stunting, malformation and coat plants in honeydew.  They also attract ants. Various insecticides are registered to manage aphids in outdoor production nurseries including Endeavor, Tristar and Trounce.  In greenhouses insecticides include Endeavor, Intercept and Enstar EW.  Where populations aren’t immediately economically damaging, biological control (e.g. Aphidius, Aphidoletes) may provide excellent management when introduced on a regular basis.  Biocontrol suppliers include Biobest, Koppert, Plant Products and Canadian Hydrogardens.

image0001 Gypsy moth larvae are starting to pupate at this time.   Sticky bands around trunks during the July flight period will help trap female Gypsy moths and will attract males to the sticky surface as well.

Two-spotted spider mites (TSSM) is showing up on several deciduous and herbaceous plants, especially in container production. 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).

Two spotted spider 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.  In the greenhouse, biocontrol agents should be brought in to coincide with the first sign of TSSM.  Phytoseiulus persimilis is a predatory mite that feeds on TSSM when temperatures are below 26oC and it is a good choice when TSSM populations are low-moderate.  Amblyseius californicus is a predatory mite that can be brought in ahead of TSSM appearance (because it can find other sources of food).

<a href="/clm/species/parthenolecanium_corni"><em>Parthenolecanium corni</em></a> (European Fruit Lecanium Scale) adult.European fruit lecanium scale on deciduous trees such as oak, ash and maple have laid their eggs and CRAWLERS are starting to hatch.  Crawlers are still hiding under the protective cover of the adult female shells in the field/landscape north of 401.  Development will be faster on infested container grown ornamentals.  Check out our new video to see crawlers.  In the landscape, well place applications of insecticidal soap and or the summer rate of horticultural oil can be effective but 2-3 applications, about a week apart are necessary to target staggered, slow crawler emergence.


The first generation of Euonymus scale crawlers and Fletcher scale crawlers are active on Euonymus and yew (Taxus) at this time and are very susceptible to insecticides.  Try insecticidal soap and where possible the summer rate of horticultural oil in the landscape.

Look for crooked, wilting and browning terminal shoots on pine and spruce with sap weeping and cankered-looking bark, it could be boring larvae from white pine weevil.

DiebackTerminalColSpruceWhite Pine Weevil Injury Terminal

Where appropriate, slice into bark and look for tiny, fat, white, legless grubs feeding in the cambium.


Insecticide control for white pine weevil is too late at this point, prune out and destroy all symptomatic terminals and train a new leader.

<a href="/clm/species/neodiprion_lecontei"><em>Neodiprion lecontei</em></a> (Redhead Pine Sawfly) larvae on pine.Look for newly hatched larvae of Redheaded pine sawfly (small yellow larvae with black spots and a reddish head feeding on OLD needles) on red and Scots pine.  Success (spinosad) is a good, low toxicity choice to manage sawfly larvae.  Several other insecticides are effective in nursery production including Pounce and Tristar.

Cedar leaf miner (CLM) ADULT moths may still be active, there are several moth species that are leafminers of Thuja.


Tear along the margin of green and brown tissue and check for the presence of hollowed out tissue to confirm it is cedar leafminer damage.  We have seen quite a bit of CLM in field grown Thuja on sandy soils this spring.  Adulticides (malathion) are registered for the moth life stage in nursery production.


Spruce Spider Mite 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.  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).

PLEASE NOTE: The previous 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.

 pub840coverjl  The 2013 Crop Protection Guide for Nursery and Landscape Plants   (previously 383, now publication 840) can now be found at:  http://www.omafra.gov.on.ca/english/crops/pub840/p840order.htm   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.

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: www.ontario.ca/bwa5

JenAndDave_08 Nursery-Landscape Insect Pest ID: Dave Cheung’s Common Pests of Nursery-Landscape database to help ID your problem pests. Check out www.dkbdigitaldesigns.com/clm

About Jen Llewellyn

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

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