Scale on Pachysandra - Ask Extension
Which scale is most often found on Pachysandra? And at what GDD base 50 can you expect to see the crawlers?
Knowledgebase
Scale on Pachysandra #864646
Asked April 15, 2024, 4:54 PM EDT
Which scale is most often found on Pachysandra? And at what GDD base 50 can you expect to see the crawlers?
Berrien County Michigan
Expert Response
Hi Roger,
Dormant oils are effective on the overwintering stage of most species, but they can only be applied in early spring before leaves appear. Adult scales are protected from insecticides by waxy coverings. Control measures, therefore, must be aimed at unprotected immature's (crawlers) or the overwintering stage. During the summer, control requires accurate identification of the pest species so that hatching dates of crawlers can be determined. Once the pest is identified and proper timing known, any one of several common insecticides can be used.
Types of Scales: Scale insects can be roughly divided into two groups: armored scales and soft scales. Armored scales are so named because they secrete a protective cover over their bodies. Most species overwinter as eggs beneath the female cover. In spring, eggs hatch into tiny mobile crawlers, which migrate to new feeding sites. After a few days, crawlers settle, insert their mouthparts, and begin feeding. Soon they secrete a protective cover and lose their legs. Large populations can build up unnoticed before plants begin to show visible symptoms. It is important to have the type of scale identified so you will know the month and time to spray with dormant oils to be sure to catch the crawlers. If you would like to send a picture, I can try to id the type of scale you are having problems with.
Thank you for using Ask Extension.
Pam V.
MSUE Master Gardener
Dormant oils are effective on the overwintering stage of most species, but they can only be applied in early spring before leaves appear. Adult scales are protected from insecticides by waxy coverings. Control measures, therefore, must be aimed at unprotected immature's (crawlers) or the overwintering stage. During the summer, control requires accurate identification of the pest species so that hatching dates of crawlers can be determined. Once the pest is identified and proper timing known, any one of several common insecticides can be used.
Types of Scales: Scale insects can be roughly divided into two groups: armored scales and soft scales. Armored scales are so named because they secrete a protective cover over their bodies. Most species overwinter as eggs beneath the female cover. In spring, eggs hatch into tiny mobile crawlers, which migrate to new feeding sites. After a few days, crawlers settle, insert their mouthparts, and begin feeding. Soon they secrete a protective cover and lose their legs. Large populations can build up unnoticed before plants begin to show visible symptoms. It is important to have the type of scale identified so you will know the month and time to spray with dormant oils to be sure to catch the crawlers. If you would like to send a picture, I can try to id the type of scale you are having problems with.
Thank you for using Ask Extension.
Pam V.
MSUE Master Gardener
Pam, Thank you for the information. I am pretty much aware of the strategies of the physiological determinants of when to apply a pesticide. My main concern knowing the most common Scale pest that can infest the Pachysandra and the GDD base 50 that it most commonly happens.
Thank you,
Roger
Roger,
Euonymus scale is a key pest to Pachysandra. Is this is the pest your are thinking of?
Euonymus Scale (psu.edu)
If it is, first egg hatch -1st generation GDD50 is 400 - 575.
See the attached for more info and degree day maps.
GDD of Landscape Insects - Integrated Pest Management (msu.edu)
Hope this is what you are looking for.
Pam
MSUE Master Gardener
Euonymus scale is a key pest to Pachysandra. Is this is the pest your are thinking of?
Euonymus Scale (psu.edu)
If it is, first egg hatch -1st generation GDD50 is 400 - 575.
See the attached for more info and degree day maps.
GDD of Landscape Insects - Integrated Pest Management (msu.edu)
Hope this is what you are looking for.
Pam
MSUE Master Gardener
Pam,
Yes, this is exactly what I was looking for. I'm fairly certain that Euonymus Scale is what we are dealing with. And the GDD timing coincides with any other information I have gathered. You just helped me confirm with what IPM I will use to address the issue.
Thank you so much,
Roger
You're welcome.
