Environment Canada is calling for sun this morning and high’s of (20-25oC). Clouds and showers will be moving in this afternoon and this evening. We can expect a bit of sun for Saturday morning, winds shifting to the west and then showers moving in during the afternoon 20-25oC (cooler near the lake). The sun will return on Sunday (18-20oC).
Growing Degree Day accumulations to the end of Thursday, June 9 (GDD 10oC / GDD 50oF).
(Courtesy of Environment Canada). These numbers are only a guide for monitoring purposes. The temperatures at your production facility can vary significantly from the nearest weather station.
| Borden: 189 / 340 | Oshawa: 181 / 326 | Hamilton RBG: 201 / 362 | |
| Vineland Stn: 246 / 443 | London CS: 254 / 457 | Windsor A: 289 / 520 | |
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. www.ontario.ca/pesticides
Nursery-Landscape Insect Pest ID: Dave Cheung’s Common Pests of Nursery-Landscape database is available online. Check out www.dkbdigitaldesigns.com/clm
Weed Identification ONLINE: http://www.weedinfo.ca/home.php
Growers’ Research Auction, July 14
This year’s auction will be held at Blue Sky Nursery in Beamsville (1 mile east of Beamsville on Regional Rd 81). http://www.horttrades.com/sector/growers
VARIOUS ORNAMENTALS:
Potato leafhoppers have arrived! Monitor for leafhoppers (such as potato leafhopper) on nursery crops such as Caragana, and Acer (platanoides, saccharum), especially after forage crops have been cut on neighbouring farms. Leafhoppers 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. Adult potato leafhoppers blow in from the south and will feed and lay their eggs on newly expanding leaf tissue. The soft, succulent growth we have this year is especially susceptible. Leafhopper nymphs will be hatching soon and appear as tiny, flightless, yellow-green insects that move sideways, very rapidly across the leaf. Leafhoppers (and aphids) suck plant sap from expanding foliage and cause foliage to wilt, become off-coloured and flecked. Potato leafhoppers are especially damaging because they cause foliage to become stunted and deformed, with brown-black margins (�hopper burn�). Leafhopper injury also appears as bronzing or stippling on more mature leaves. Monitor populations and treat with insecticides before damage becomes economically threatening. Leafhoppers are also attracted to yellow sticky cards, for monitoring. Registered insecticides include Tristar and Sevin XLR.
http://dkbdigitaldesigns.com/clm/species/empoasca_fabae
White grubs are pupating. May/June beetle adults have been active for a few weeks now and are laying eggs. European chafer larvae are starting to pupate in the soil. A preventative applications of Intercept (imidacloprid) is registered for white grubs in nursery production. In the field, the application period is June to July (to coincide with egg-laying). To help qualify for the Japanese beetle certification program, an application of Intercept on container stock should be some time between mid-June to July. The cut-off period for Intercept applications to comply with the JB Certification program this year may be as early as July 31st. Nematode applications for white grubs (e.g. European chafer) are not effective at this time. Try timing nematode applications for late August/early September to catch early instar larvae.
DECIDUOUS WOODY AND HERBACEOUS PERENNIALS:
Various species of aphids (e.g. green peach aphid) are being detected on deciduous and broadleaf woody plants in the greenhouse, polyhouse and now outdoor production. Because of the cool weather, foliage is much more tender and aphid populations are thriving. Biocontrol organisms are available to help suppress aphid populations in protected crops (midge: Aphidoletes and wasp: Aphidius). Insecticides registered for aphids in nursery production include: Tristar, Endeavor. Insecticide applications can be very effective where even coverage can be achieved.
Our nursery scout found peach leaf curl (Taphrina deformans) on Prunus spp. last week. This disease overwinters as spores in the buds and infects new foliage as it emerges in the spring. Leaves become puckered, curled with a reddish pigment around the leaf margins. Infected leaves will sometimes drop in summer. It’s too late for fungicide applications, damage has been done. Fungicide applications in the fall (just after leaf drop) are much more effective than they are in the spring.
Dutch Trig is registered for Dutch Elm Disease on Ulmus americana species in Canada. This is a newer registration (fall, 2009) that contains a biological organism that induces an immune response to help the tree fight off DED infections. Injections should be made on sunny days during leaf emergence to maximize uptake.
Leafrollers can be found feeding on several deciduous woody trees and shrubs. Look for leaves that are suspiciously stuck together, or rolled up and held together by webbing. You will see a yellow-green tiny caterpillar inside feeding. An evening application of B.t. (Bacillus thuringiensis) should give kill of leafrollers within 3-4 days. Success (spinosad) another low toxicity choice. Get them now before the populations totally explode. Soft growth is making it easy for leafrollers to do their thing this spring.
Woolly Beech Aphids can be found on the undersides of beech leaves at this time. Where aphids are NOT woolly, they are very susceptible to most pesticides, including insecticidal soap. Other choices include: Tristar, Trounce (malation, orthene, pyrate, thiodan).
Snowball Aphids can be found on various Viburnum opulus this spring. Look for curled up, distorted leaves that are thickened. Inside the curled up leaf you will finy tiny white cast skins, and perhaps the white, woolly aphids that are causing the injury. This is a spring feeding aphid and will complete its lifecycle soon. Most of the damage has already been done.
Viburnum leaf beetle larvae are feeding. They hatch as the foliage emerges (Viburnum carlesii in full bloom, Syringa vulgaris first bloom). The larvae are vulnerable to chemical control only during the first 7-10 days after hatch. Larvae feed on the interveinal tissue from the undersides of the leaves, keep that in mind if you are making insecticidal applications. Young larvae are most commonly found on the undersides of the newest leaves.
Adults of the imported willow leaf beetle (Plagioderaversicolora) were found on Salix discolor (Pussy Willow) in container production nursery this week. The beetles were feeding on the leaves, chewing conspicuous holes and notches into them. They are easily recognizable by their shiny, metallic black to bluish-green color. Adults overwinter in cracks within the bark on the host tree and start feeding in the spring. They will soon be laying yellow eggs on the underside of leaves, which will hatch 2 weeks after that. The larvae will feed on the interveinal tissue on the underside of the leaves and damage can be significant. The adults can be found feeding in field production and in the landscape in the coming weeks and it’s best to target adults before they start laying eggs. Low toxicity insecticides registered for this pest include Success 480 SC. Other insecticides include Malathion, Orthene and Sevin. Avoid Sevin application when Salix is in bloom.
Emerald ash borer adults will be starting to emerge soon. TreeAzin (azadirachtin, neem) is registered for emerald ash borer on ash. This is an injectable insecticide that is delivered though BioForest’s Ecoject system, to inject insecticides to help protect ash trees from this borer. For more information contact BioForest (http://www.bioforest.ca/).
The regulated areas for Emerald Ash Borer have been updated. Check out: http://www.inspection.gc.ca/english/plaveg/pestrava/agrpla/survenqe.shtml
Peach tree borer (Synanthedon exitosa) adults will be flying in the next few weeks. Look for cankered regions and chewed bark/wood in the lower stems of Prunus x cistena (and other Prunus spp.) as a sign of larval damage. The clearwing moths that emerge resemble wasps. Adults 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.
Fall Cankerworm larvae are feeding on deciduous tree leaves (Tilia, Fagus, Quercus) and wow did we see a lot of these this week! Look for green or dark grey �inchworms� feeding on the undersides and edges of leaves. They will strip leaves similar to Gypsy moth larvae (and in fact, the two can often be found feeding on the same tree). Cankerworm larvae are susceptible to Bacillus thuringienesis (Dipel, Foray), spinosad (Success) insecticides, but you will need to make B.t. applications as early in larval development as possible.
We saw small, black, adult sawflies of birch leaf miner mating and laying eggs on the foliage of Betula spp. last week. Where possible, a summer application of Landscape Oil (horticultural oil at the summer rate) can help smother adult sawflies. Various insecticides are registered for this pest in the nursery. Once leaf mines (blotches) appear, it is difficult to manage this mining pest.
Eastern tent caterpillar larvae are coming up to their heavy feeding period. Applications of B.t. (Dipel) should be taking place as soon as possible. Apply B.t. on foliage during the evening hours.
Gypsy moth larvae have hatched and are tiny, fuzzy, black caterpillars dispersing on threads to various other hosts before they settle to feed. When larvae begin to feed, some control can be achieved using Bacillus thuringienesis (Dipel, Foray) and spinosad (Success) insecticide in the first 2 weeks after egg hatch. Some keen homeowners can install a burlap skirt at the base of the tree to create a shady, protected area for larvae to hide during the day (this behaviour usually peaks near the end of May). Homeowners will need to inspect burlap skirts and underlying bark crevices daily (1-3 pm is best) and remove/destroy larvae. Sticky bands around trunks will help prevent females from laying eggs above sticky bands and will attract males to the sticky surface.
The first generation of Euonymus scale crawlers will be hatching in the field and landscape. Euonymus scale look like tiny white (males) and brown (females) flecks along twigs and the undersides of leaves. Look for bright, orange crawlers around populations of adults and on the undersides of leaves and twigs. Where insecticide applications are warranted, multiple applications may be required to get good knockdown since crawler emergence is staggered over a few weeks. Try insecticidal soap and the summer rate of horticultural oil.
Oystershell scale eggs are hatching in southwestern Ontario. The nymphs will be hatching and looking for new feeding sites over the next few weeks. Adult scales look like miniature sea shells, often twisted to one side and there can be several generations of dead adults caked onto stems and branches. They are small scale insects, about 3mm long when mature. They feed on the twigs of Fraxinus, Acer, Quercus, Malus, Syringa and Tilia. Crawlers begin to hatch when the Philadelphus begins to bloom and the Syringa patula ‘Miss Kim’ are in full bloom. Treat crawlers at PEAK egg hatch, about 7-10 days after crawlers start to hatch. Repeat applications 2-3 times since crawler hatch is staggered. Try Landscape Oil and insecticidal soap.
Two-spotted spider mites (TSSM) will be showing up on greenhouse grown ornamentals (woody and herbaceous) soon. TSSM will be showing up on field grown crops soon. 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, Shuttle, Floramite, Avid and Kelthane. 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).
EVERGREENS:
Where new foliage is emerging on conifers, monitor for needlecast and blight diseases in the area. Diplodia tip blight on 2 and 3 needled pines and Rhizosphaera needlecast and Stigmina on blue Colorado spruce are our most common needlecast diseases in Ontario. Diplodia tip blight appears as brown, stunted needles at the tips of branches. Rhizosphaera appears as brown-purplish needles from the previous year’s growth, symptomatic needles begin to drop in late spring. Stigmina appears on green and chlorotic needles, but doesn’t always lead to needle drop. To confirm it is Rhizosphaera, look at the undersides of the needles. Those little white dots (stomata) will turn black and the black spots will protrude during sporulation. New, soft growth is especially susceptible to foliar diseases, but infection may also take place later in the season (we don’t know). Where there is a history of damage, treat with registered fungicides (copper oxychloride, Daconil) as buds start to open and protect new foliage. Apply fungicides prior to precipitation events (spore dispersal). Unfortunately, most of these blights and needlecasts can be found sporulating for much of the year.
Brown shoots on juniper may be a symptom of juniper tip blight (Kabatina is the fungus most commonly found in S. Ontario samples). We saw some on Juniperus scopulorum last week. A small grey band or pinched grey canker can be found at the base of the infected shoot, this is where the spores come from in early fall. Where plants are still dormant, PRUNE OUT DEAD SHOOTS during DRY conditions and remove shoots to reduce disease spread. Disinfect pruning shears between each cut (e.g. rubbing alcohol, other sterilants) to reduce disease spread. Where cankers are found, copper and Dithane are registered to protect new growth in summer.
Volutella blight on boxwood has been detected on some propagative stock of boxwood. Symptoms include black tissue discolouration along stems, tiny orange cushion-like fruiting structures and tip dieback and browning. Although the disease is worse in propagation zones, it can also be found in field production in moderate amounts. Volutella sporulates in field production in mid-late spring. Care should be taken to avoid introducing Volutella blight through cuttings from infected plants. Remember, Volutella is often associated with wounds, keep the mother plants protect with fungicides once any pruning or cuttings are taken in the spring.
The second generation of Balsam twig aphids can be found feeding on the new shoots of fir, white spruce, Colorado spruce and juniper, they are very difficult to manage with insecticide applications. Look for blue-green aphids and woolly masses of wax feeding on twisted/distorted new needles.
European pine sawfly larvae are feeding on last year’s pine needles. Look for small, green-tan larvae with dark heads clustered against needles. Where they are still feeding in a tight cluster, they can be destroyed or manually removed. A low toxic pesticide choice is Success. Closely examine pine trees and shrubs such as Pinus sylvestris, Pinus mugo, Pinus nigra.
Look for small black and orange (males) or orange (females) sawflies mating and laying eggs on new growth of spruce as adult Yellow-headed spruce sawfly. The adults are quite active on new shoots of spruce. There are several insecticides registered including Dragnet, Dylox, Pounce and Success to target young larvae. Larvae are green with lighter longitudinal stripes, yellow-brown heads. This is a significant pest of spruce in York region and has caused significant damage to spruce trees. http://www.dkbdigitaldesigns.com/clm/species/pikonema_alaskensis
Spruce budworm (Choristoneura fumiferana) can be found on the new growth of spruce at this time. In spring, the early instar larvae feed on male flowers and may mine buds and needles. Older larvae feed on expanding shoots, destroying them before they can fully elongate. The small, green larvae were detected because of small patches of browned foliage that had tiny nests made of shoots wrapped together by silk. Larvae can cause defoliation and also browning of the needles. B.t. (Dipel) is an excellent biological insecticide for suppressing spruce budworm populations in mid-late spring.
Cedar leaf miner adults, the tiny silvery-white moths have appeared on foliage in the southwest. Tear along the margin of green and brown tissue and check for the presence of tiny, brown pupa or just empty tissue (to confirm CLM is the cause of the browning foliage). It is likely too late to prune out infested foliage. Foliar applications of systemic insecticides are much more effective when applied to young larvae (August). If no larvae can be found and interior tissue seems to be intact, CLM is not likely the cause of foliar damage (winter desiccation may be suspect).
Most white pine weevil adults have finished laying their eggs and those eggs will be hatching into larvae inside 2010 terminals. Insecticide applications are futile at this point but do inspect white pine, Norway and Serbian spruce for wilting or hooking terminals in the coming weeks. Prune out, destroy and train a new leader.
Pine shoot beetle larvae are actively feeding inside the cambium, just under the bark. Remove brood material (i.e. trap (sentinel) logs, snags, dead/dying trees) before new progeny adults emerge (210 GDD, Base 10oC) to comply with the CFIA. All brood material must be burned, chipped (less than 2cm diameter) or buried (30 cm deep) to comply with CFIA standards.
Monitor for black vine weevil larvae and pupae in the FIELD and LANDSCAPE for Rhododendron, Taxus, Thuja and Euonymus. Black vine weevil adults will be emerging in the next few week in the field. 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 will be emerging in the next couple of weeks or so. Insecticides for adult weevils in the nursery include Pounce, Sevin and Thiodan.
Black vine weevil adults are active in container production. Where black vine weevil larvae are a problem in CONTAINER PRODUCTION (e.g. perennials, evergreens), insecticide applications can be made to target the adult stage. Nematode applications for larvae will have to wait for late summer/early autumn.
European pine sawfly larvae are actively feeding on foliage of pine. Look for green-tan larvae with dark heads clustered against needles (they really blend in against the foliage!). A low toxic pesticide choice is Success. Closely examine pine trees and shrubs such as Pinus sylvestris, Pinus mugo, Pinus nigra.
Taxus or Fletcher Scale nymphs are active on foliage of Thuja and Taxus. Applications of insecticides may give some suppression of this pest at this time (but nymphs were more susceptible in mid-to-late summer of last year). Nymphs are feeding and producing copious amounts of honeydew (sticky, sugary residue on needles below infestation).
Juniper scale crawlers will be hatching soon. Look for tiny, white flecks on the needles of Juniperus and Thuja. Adults scales look like tiny, white, twisted sea shells. Crawlers are yellow and can be found amongst dead, adult scales and on the foliage of infested plants. Where insecticide applications are warranted, multiple applications may be required to get good knockdown since crawler emergence is staggered over a few weeks. Try insecticidal soap and the summer rate of horticultural oil.
Monitor for spruce spider mites on conifers with a history of mite damage. Newly hatched spruce spider mites are reddish and very tiny (visible mainly with hand lens). Monitor lower branches, this is where most of the feeding damage is done. Horticultural oil applications to target overwintering eggs should be finishing up now and miticide applications (e.g. Floramite, Kanemite, Vendex) should be ready to go for when mite eggs hatch in the coming weeks (Magnolia x soulangiana in full bloom). – See more at: https://lawnsavers.com/nursery-and-landscape-report-2011/nursery-and-landscape-report-for-june-10-2011.html#sthash.csiBRSU9.dpuf
