Control opportunities exist now for controlling Lecanium scales. The following is more information.
Two species of Lecanium scales are problematic in our landscapes and the next few weeks offer good management opportunities. Fletcher scale (Parthenolecanium fletcheri) affects a wide variety of coniferous plants such as Taxus, arborvitae, junipers, and even Taxodium spp.. European fruit lecanium (Parthenolecanium corni) affects a broad range of broadleaved woody plants such as redbud, hawthorn, dogwood, and oak.
Lecanium scale adults appear like little brown lumps grouped along branches. They feed on plant sap and leave a clear sticky substance (honeydew the scales' excrement) that gets on leaves, cars, etc. A black fungus called sooty mold often grows on it. European fruit lecanium has eggs (1000-3500/female) by May 9 and production occurs from 319-1328 GDD (median=654).
For Fletcher scale, eggs were noted by April 16 and continued from 171-1438 GDD (median=592). There is one generation per year. The crawler (hatchling nymph) stages look like tiny yellow-orange dots when tapped onto a white sheet of paper. Crawlers were seen in our area this past week and are later this year than the normal median crawler observations (between 850-900 GDD). The crawlers will migrate to the undersides of leaves/needles and spend the summer months there then migrate back to the branches to spend the fall and winter. They will resume growth, mate, and lay eggs the following spring.
The settled crawler stage is the best time to control lecanium scales. Many insecticidal products are registered for this purpose. Horticultural oil (1-2% v:v) applications work quite well. Occasionally, a re-application of oil is needed about 3 weeks after the initial application to ensure all crawlers have emerged and settled. Many naturally occurring parasites also control lecanium scales look for tiny holes in the adult scale's cover. Many predators like lady beetles also feed on lecanium scales. Insecticides sprayed well after crawlers have settled provide only limited effectiveness. Soil systemic insecticide applications of neonicotinoids such as imidacloprid (Merit) and Dinotefuran (Safari) work well against lecanium scales if applied in advance.
Information from Casey Sclar, IPM Coordinator, Longwood Gardens
Showing posts with label european fruit lecanium scale. Show all posts
Showing posts with label european fruit lecanium scale. Show all posts
Saturday, July 25, 2009
Sunday, April 5, 2009
Landscape - Scale Insects: European Fruit Lecanium
This is the third in a series on scale insects in the landscape. It is a description of the European Fruit Lecanium. Information is from the University of Maryland.
European Fruit Lecanium (Parthenolecanium corni), Family Coccidae
Plants Damaged: This soft scale occurs on many shade tree species including hawthorn, red maple, pyracantha, and other plants in the rose family. The European fruit lecanium is a common soft scale insect pest of shade trees and other woody ornamental plants in Maryland (and Delaware). This species feeds on a wide range of host plants and is considered polyphagous. Populations of this pest build up quickly so monitoring for this pest on potential host plants is important.
Damage Symptoms: Feeding damage may cause curled, chlorotic foliage that may drop prematurely. Smaller infested branches are weakened due to feeding injury or in some cases may be killed. Also, when this soft scale species is feeding on leaves and twigs, a large quantity of honeydew is secreted.
Life Cycle: The 2nd instar females overwinter on the branches. The females will start to swell-up in May and crawlers emerge in late May to early June. Nymphs move out onto foliage where they feed in summer and migrate back to the stems and trunk to overwinter.
Monitoring: Look for sooty mold growing on the honeydew excreted on the foliage and branches. Inspect branches using a 10 -16X magnifier for crawlers
Control: Distance and 1% horticultural oil applied when crawlers are active gives good control. Another option is soil applications of imidacloprid or dinotefuran as a soil drench.
European Fruit Lecanium. Photo by Raymond Gill, California Department of Food and Agriculture, Bugwood.org
Information from "Scales Commonly Encountered in Maryland Landscapes and Nurseries" by Stanton Gill, Extension Specialist in IPM for Nurseries and Greenhouses,and Suzanne Klick and Shannon Wadkins, Technicians, Central Maryland Research and Education Center University of Maryland Cooperative Extension.
European Fruit Lecanium (Parthenolecanium corni), Family Coccidae
Plants Damaged: This soft scale occurs on many shade tree species including hawthorn, red maple, pyracantha, and other plants in the rose family. The European fruit lecanium is a common soft scale insect pest of shade trees and other woody ornamental plants in Maryland (and Delaware). This species feeds on a wide range of host plants and is considered polyphagous. Populations of this pest build up quickly so monitoring for this pest on potential host plants is important.
Damage Symptoms: Feeding damage may cause curled, chlorotic foliage that may drop prematurely. Smaller infested branches are weakened due to feeding injury or in some cases may be killed. Also, when this soft scale species is feeding on leaves and twigs, a large quantity of honeydew is secreted.
Life Cycle: The 2nd instar females overwinter on the branches. The females will start to swell-up in May and crawlers emerge in late May to early June. Nymphs move out onto foliage where they feed in summer and migrate back to the stems and trunk to overwinter.
Monitoring: Look for sooty mold growing on the honeydew excreted on the foliage and branches. Inspect branches using a 10 -16X magnifier for crawlers
Control: Distance and 1% horticultural oil applied when crawlers are active gives good control. Another option is soil applications of imidacloprid or dinotefuran as a soil drench.
European Fruit Lecanium. Photo by Raymond Gill, California Department of Food and Agriculture, Bugwood.org
Information from "Scales Commonly Encountered in Maryland Landscapes and Nurseries" by Stanton Gill, Extension Specialist in IPM for Nurseries and Greenhouses,and Suzanne Klick and Shannon Wadkins, Technicians, Central Maryland Research and Education Center University of Maryland Cooperative Extension.
Friday, May 30, 2008
Landscape and Nursery - Scales to Watch For
The following is information on some scale pests you should watch for and apply control measures in the next few weeks.
Two species of Lecanium scales are problematic in our landscapes and the next few weeks offer good management opportunities. Fletcher scale (Parthenolecanium fletcheri) affects a wide variety of coniferous plants such as Taxus, arborvitae, junipers, and even Taxodium spp.. European fruit lecanium (Parthenolecanium corni) affects a broad range of broadleaved woody plants such as redbud, hawthorn, dogwood, and oak.
These soft scales appear like little brown lumps grouped along tree branches as adults. They feed in the phloem (on plant sap). Honeydew rain (clear sticky substance that is scale excrement) from the developing nymphs and adults of both species was noticeable in early May. A black fungus called sooty mold often grows on the honeydew.
Lecanium scales have one generation per year. Crawlers will start to appear in early June and will migrate to the undersides of leaves/needles and spend the summer months there then migrate back to the branches to spend the fall and winter. They will resume growth, mate, and lay eggs the following spring.
The settled crawler stage is the best time to control lecanium scales. Many insecticidal products are registered for this purpose but horticultural oils work quite well. Occasionally, a re-application is needed about 3 weeks after the initial application to ensure that all crawlers have emerged. Many naturally occurring parasites and predators often control lecanium scales,
but parasites have been less active recently on a regional level. Still, many predators such as lady beetles feed on them. Insecticides sprayed later provide only limited effectiveness against nymphs and soil systemic insecticide applications must be properly timed.
Information from Casey Sclar, IPM Coordinator, Longwood Gardens
Two species of Lecanium scales are problematic in our landscapes and the next few weeks offer good management opportunities. Fletcher scale (Parthenolecanium fletcheri) affects a wide variety of coniferous plants such as Taxus, arborvitae, junipers, and even Taxodium spp.. European fruit lecanium (Parthenolecanium corni) affects a broad range of broadleaved woody plants such as redbud, hawthorn, dogwood, and oak.
These soft scales appear like little brown lumps grouped along tree branches as adults. They feed in the phloem (on plant sap). Honeydew rain (clear sticky substance that is scale excrement) from the developing nymphs and adults of both species was noticeable in early May. A black fungus called sooty mold often grows on the honeydew.
Lecanium scales have one generation per year. Crawlers will start to appear in early June and will migrate to the undersides of leaves/needles and spend the summer months there then migrate back to the branches to spend the fall and winter. They will resume growth, mate, and lay eggs the following spring.
The settled crawler stage is the best time to control lecanium scales. Many insecticidal products are registered for this purpose but horticultural oils work quite well. Occasionally, a re-application is needed about 3 weeks after the initial application to ensure that all crawlers have emerged. Many naturally occurring parasites and predators often control lecanium scales,
but parasites have been less active recently on a regional level. Still, many predators such as lady beetles feed on them. Insecticides sprayed later provide only limited effectiveness against nymphs and soil systemic insecticide applications must be properly timed.
Information from Casey Sclar, IPM Coordinator, Longwood Gardens
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