July 15, 2009
Spring brings plethora of pests
By Jen Llewellyn
OMAFRA Nursery Crops Specialist
We’ve just made it out of a soggy and cool spring, with some climatologists forecasting the possibility of a hotter-than-average summer in Ontario. Our crops could certainly use the heat. As a grower, retailer or landscaper, I’m sure you have been pretty frustrated by the weather and the plethora of pests this spring.
I cannot remember a spring where aphids, of several species, could be found just about everywhere you looked. In the landscape, we commonly see green peach aphid, foxglove aphid and other species that are host specific (e.g. snowball aphid on Viburnum). This spring I received countless inquiries about aphids and honeydew. I think the slow spring had a hand in our aphid situation.
Aphids have delicate, sucking mouthparts which they insert into soft plant tissue to feed on plant sap. This is why you will often find them on the newest leaves, flowers and stems. Once the plant’s cuticle develops and tissues harden off, aphids have a much more difficult time feeding on this tissue. During a cooler spring, plants take longer to leaf out and harden off. This means that aphids and other sucking insects have a longer window of opportunity. Plus, aphids can develop from immature to reproductive adults in a matter of days. This pest obviously managed to fit in several generations this spring.
Several pesticides are available to help manage aphids in nursery production. Make sure you are rotating between chemical families. Under the Cosmetic Pesticide Ban (regulation 63/09), insecticidal soap may be used to manage this pest in the landscape. There are exemptions for tree health, as long as certain criteria are met. See www.ontario.ca/pesticideban for more information.
Hydrangea arborescens ‘Grandiflora’, flowers white to green
Daucus carota, full bloom
Hibiscus syriacus, early bloom
Sorbus aucuparia fruit yellow
Monitor for the following insects and diseases:
b) In areas where the following phenology plants (900-1100 GDD Base 10oC)
Solidago canadensis are in early to full bloom
Hibiscus syriacus are in full bloom
Hydrangea arborescens ‘Grandiflora’ are in late to finishing bloom
Viburnum lantana are fruiting
Sorbus aucuparia have orange fruit
Monitor for the following insects and diseases:
Contact Jennifer Llewellyn at 519-824-4120, ext. 52671, fax: 519-767-0755, or e-mail: jennifer.llewellyn@ontario.ca. See the Nursery-Landscape Report at http://apps.omafra.gov.on.ca/scripts/english/crops/agriphone/index.asp.
OMAFRA Nursery Crops Specialist
We’ve just made it out of a soggy and cool spring, with some climatologists forecasting the possibility of a hotter-than-average summer in Ontario. Our crops could certainly use the heat. As a grower, retailer or landscaper, I’m sure you have been pretty frustrated by the weather and the plethora of pests this spring.
I cannot remember a spring where aphids, of several species, could be found just about everywhere you looked. In the landscape, we commonly see green peach aphid, foxglove aphid and other species that are host specific (e.g. snowball aphid on Viburnum). This spring I received countless inquiries about aphids and honeydew. I think the slow spring had a hand in our aphid situation.
Aphids have delicate, sucking mouthparts which they insert into soft plant tissue to feed on plant sap. This is why you will often find them on the newest leaves, flowers and stems. Once the plant’s cuticle develops and tissues harden off, aphids have a much more difficult time feeding on this tissue. During a cooler spring, plants take longer to leaf out and harden off. This means that aphids and other sucking insects have a longer window of opportunity. Plus, aphids can develop from immature to reproductive adults in a matter of days. This pest obviously managed to fit in several generations this spring.
Several pesticides are available to help manage aphids in nursery production. Make sure you are rotating between chemical families. Under the Cosmetic Pesticide Ban (regulation 63/09), insecticidal soap may be used to manage this pest in the landscape. There are exemptions for tree health, as long as certain criteria are met. See www.ontario.ca/pesticideban for more information.
Diseases and insect pests in mid-July to mid-August
Check out OMAFRA Publication 383, Nursery and Landscape Plant Production and IPM for more detailed monitoring tables (Chapter #3). To order, call 1-800-668-9938.Monitor insects and diseases
a) In areas where the following phenology plants (700-900 GDD Base 10oC):Hydrangea arborescens ‘Grandiflora’, flowers white to green
Daucus carota, full bloom
Hibiscus syriacus, early bloom
Sorbus aucuparia fruit yellow
Monitor for the following insects and diseases:
| PLANT | PEST |
| ash | leopard moth (larvae), emerald ash borer (adults, eggs, larvae), fall webworm (larvae) |
| deciduous trees | aphids, plant bugs (nymphs, adults), leafhoppers (nymphs, adults) |
| euonymus | black vine weevil (adults, eggs), euonymus scale (2nd generation crawlers) |
| honeylocust | honeylocust mite |
| pine | white pine weevil (larvae, pupae), pine needle scale (2nd gen crawlers), pine sawfly (larvae), European pine shoot moth (larvae) |
| rose | rose chafer (adults), rose slug [sawfly] (larvae), two spotted spider mite |
| rose, linden, cherry | rose chafer (adults), rose slug [sawfly] (larvae), two-spotted spider mite (adults, eggs) |
| spruce | Japanese beetle (adults), strawberry root weevil (adults, eggs), white pine weevil (larvae, pupae) |
| yew, cedar | Taxus/Fletcher scale (nymphs), black vine weevil (adults), strawberry root weevil (adults) |
Solidago canadensis are in early to full bloom
Hibiscus syriacus are in full bloom
Hydrangea arborescens ‘Grandiflora’ are in late to finishing bloom
Viburnum lantana are fruiting
Sorbus aucuparia have orange fruit
Monitor for the following insects and diseases:
| PLANT | PEST |
| ash | leopard moth (larvae), emerald ash borer (adults, eggs, larvae), fall webworm (larvae) |
| cherry | peach tree borer (larvae) |
| deciduous trees | aphids, plant bugs (nymphs, adults), leafhoppers (nymphs, adults) |
| euonymus | black vine weevil (adults, eggs), euonymus scale (2nd generation crawlers) |
| honeylocust | honeylocust mite |
| magnolia | magnolia scale (eggs, crawlers) |
| pine | white pine weevil (larvae, pupae), pine needle scale (2nd gen crawlers), pine sawfly (larvae), European pine shoot moth (larvae) |
| rose | rose chafer (adults), rose slug [sawfly] (larvae), two spotted spider mite |
| rose, linden, cherry | rose chafer (adults), rose slug [sawfly] (larvae), two-spotted spider mite (adults, eggs) |
| spruce | Japanese beetle (adults), strawberry root weevil (adults, eggs), white pine weevil (larvae, pupae) |
| yew, cedar | Taxus/Fletcher scale (nymphs), black vine weevil (adults, eggs), strawberry root weevil (adults, eggs) |
Contact Jennifer Llewellyn at 519-824-4120, ext. 52671, fax: 519-767-0755, or e-mail: jennifer.llewellyn@ontario.ca. See the Nursery-Landscape Report at http://apps.omafra.gov.on.ca/scripts/english/crops/agriphone/index.asp.