You have reached Jen Llewellyn for the 13th edition of the 2013 OMAF and MRA Nursery and Landscape Report, updated on Friday, July 12th.
Environment Canada is calling for sun and cloud for today and tomorrow, winds will be out of the NW at 15-20 km/hr. It’s going to get ridiculously hot and humid again Sunday and the heat wave will continue well into next week.
Have you seen fuzzy, yellow caterpillars feeding on ornamentals in the nursery or landscape? They might look cute but they do A LOT of damage if there are groups of them. They are tiger moths, and the ones we see feeding on nursery crops this year we call “yellow wooly bears”. Or you might call them “hoochie-goochie-woochies” until you see how much foliage they can eat. They can be found feeding on some of your favorite herbaceous perennials and deciduous flowering shrubs. Try foliar applications of Bacillus thuringiensis (B.t.) in products such as Dipel. B.t. is a biological insecticide that kills caterpillars after they ingest it by feeding on treated foliage. It does not harm other types of insects.
Plant Phenology indicators this week.
A) North of 401 (300-400 GDD Base 10oC): Daucus carota (wild carrot, early bloom), Hydrangea arborescens ‘Grandiflora’ (full to late bloom), Sambucus canadensis (full bloom), Yucca filamentosa (full bloom)
B) Niagara: Daucus carota (wild carrot, full bloom), Hydrangea arborescens ‘Grandiflora’ (late bloom to flowers starting to turn greenish), Sambucus canadensis (full to late bloom), Yucca filamentosa (full to late bloom)
C) London area: if you would like to report plant phenology events, please contact me.
D) Leamington-Windsor: if you would like to report plant phenology events, please contact me.
If you are referring to the Monitoring tables in the 2009 edition of publication 383, Nursery and Landscape Plant Production and IPM, look at Tables starting on pg. 64.
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.
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.
Nursery-Landscape Insect Pest ID: Dave Cheung’s Common Pests of Nursery-Landscape database to help ID your problem pests. Check out
Growers. Thursday, August 15 at J.C. Bakker & Sons Nurseries. “Intelligent Sprayer Demo Day”. If a new sprayer design could reduce crop protection inputs by 70 per cent, would you be interested? Come and see for yourself, the “intelligent sprayer”, designed and customized for nursery production systems, will be demonstrated for its efficiency and efficacy on real-life commercial nursery crops. Dr. Heping Zhu, well known for his extension work at Ohio State University and associate Randy Zondag will be sharing their latest research with us in St. Catharines. Rain day: August 16. RSVP only. To register, click here.
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 they usually start to show up on the ends of branches this time of year. 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 necessary or necessarily effective unless there are high populations of nests.
Have white grubs been an issue in your nursery? Preventative applications of Intercept (imidacloprid) are registered for white grubs (nursery production) and the application period is in June and July (during the adult flight period for the adult stage). To help qualify for the Japanese beetle certification program, an application of Intercept 60WP on container stock or field stock should made between mid-June to July (adult flight period). The cut-off period for Intercept applications to comply with the JB Certification program this year may be as early as July 31st. [Beneficial nematode applications for white grubs (e.g. European chafer) are not effective at
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.
Adulticide insecticides for JB in the nursery include Sevin XLR and Thionex. Pheromone traps for JB are extremely good at attracting the adults. Always place traps far AWAY from susceptible host trees and shrubs (e.g. roses, cherry etc.).
DECIDUOUS WOODY AND HERBACEOUS PERENNIALS:
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 (biofungicide), Tivano] where the history of disease pressure is moderate to high.
A few Emerald ash borer adults may still be flying and feeding on ash leaves and laying eggs.
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 EAB outlines restrictions on the movement of all ash species (Fraxinus sp.) materials and all species of firewood from these regulated areas of Ontario and Quebec. The regulated areas for Emerald Ash Borer in Ontario and Quebec can be found at:
Adult bronze birch borer beetles are actively 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.
Honeylocust plant bug NYMPHS and ADULTS are plaguing Honeylocust trees big time this year and these populations are starting to level off. The tiny, green plant bugs will actually rain down on you if you stand underneathe them or give the branch a little shake. Treat nymphs with Insecticidal Soap to reduce populations. Adults are very mobile and much more difficult to contact with insecticides. Overlapping life stages exist at this point, management with insecticides is difficult.
Potato leafhoppers NYMPHS and ADULTS are still feeding on woody nursery stock on the newest growth. Monitor for potato leafhopper on nursery crops such as Caragana, and Acer (platanoides, saccharum). Nymphs are about 2 mm long and scuttle SIDEWAYS, rather quickly, across the leaf and to the other side (they don’t have wings to fly away). Susceptible crops are those that are flushing new leaves (leafhopper’s favourite food source). Older, hardened off foliage is not usually as susceptible. Leafhopper adults are winged, are very mobile, tiny, pale yellow-green jumping insects that are easily disturbed when you approach infested foliage. It almost looks as though they are being flicked off of the foliage. Leafhoppers (and aphids) suck plant sap from soft, expanding foliage and cause foliage to wilt, turn brown/black (‘Hopper Burn”) and become stunted and malformed. Older, hardened off foliage will become flecked from 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 were quite numerous on herbaceous and woody ornamentals this year but they are starting to die off because they don’t do very well on hardened off foliage. 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.
Gypsy moth larvae are pupating and no longer susceptible to insecticides.
Sticky bands around trunks during the June/July flight period will help prevent adult female Gypsy moths from laying eggs above sticky bands and will attract males to the sticky surface. Pheromone-baited sticky traps are also available to help reduce populations of adult males.
Two-spotted spider mites (TSSM) are feeding on several types of deciduous woody (Viburnum and Spiraea in container production) 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.
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. 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). Stethorus punctillium is a new beetle that is a good predator of TSSM.
Look for crooked, wilting and browning terminal shoots on pine and spruce, it could be boring larvae from white pine weevil. Where appropriate, slice into bark and look for tiny, fat, white, legless grubs feeding in the cambium. Insecticide control is too late at this point, prune out and destroy all symptomatic terminals and train a new leader.
Taxus or Fletcher Scale crawlers (left) have settled on needles and twigs and are feeding (right). These eggs have been hatching over the last few weeks ( look for “eggs with legs“). Crawlers are really tiny, clear-white and REALLY difficult to see. Crawlers will hide under females shells and will hatch over a period of 2-3 weeks. Therefore, two-three applications of insecticide will be needed to reduce crawler populations and reduce further injury. Insecticidal soap and several contact insecticides are registered for Fletcher scale crawlers. Crawlers are starting to settle and feed.
Monitor for black vine weevil ADULTS in the FIELD and LANDSCAPE for Rhododendron, Taxus, Thuja and Euonymus. It’s too late for applications of nematodes in the field/landscape. Strawberry root weevil can also be a problem in field production of evergreens, adults have emerged. Signs of strawberry root weevil adults include brown, flagging shoot tips (and small girdling marks at the base of the flagged shoot) on Thuja (eastern white cedar). To scout for adult weevils, place a tarp or large piece of card board under the tree, shake branches vigorously and look for brown-black weevils “playing dead”. Insecticides for adult weevils in the nursery include Pounce, Sevin and Thiodan. Remember, adult weevils feed at night. Spray insecticides in late evening to target adults and reduce UV degradation (e.g. Pounce, Scimitar).
Cedar leaf miner (CLM) next generation larvae are starting to hatch and feed on tender new foliage. A light sheering of tips in early August should give good knockdown of CLM larvae. Cygon is registered as a foliar application for CLM larvae in early August in the nursery.
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.
THIS MESSAGE WILL BE UPDATED the week of July 22.