Jack pine tree white spots

(Question)

Im having issues with my trees this year and am looking for something to save them the pine tree has white spots on the needles on the lower branches. Would appreciate any advice you can give me. I’ll try and send a photo.

(Answer)

Hello:

Your picture is a little bit fuzzy but dots that look like small splashes of white paint or resin on the needles are the winter homes of an insect pest called pine needle scale (Chionaspis pinifoliae). These insects suck plant sap. Light infestations often go unnoticed and cause little damage. A bad infestation can cause whole branches to die, or even in severe cases, kill the tree.
Pine needle scale is an armoured scale – meaning they make a hard waxy shell (white in the picture) that protects overwintering eggs and females from predators such as us.
You could prune out very heavily infested branches, but that is all you can do at this time of year. There are chemicals than can be used to treat scale, but the Ontario Pesticides Ban limits our options there. We can’t use Class 9 pecticides often recommended elsewhere. What you can do is spray with summer horticultural oil (lighter weight than dormant oil) or insecticidal soaps. The timing of spraying is very important – spraying only works if you spray the soft-bodied crawlers or nymphs after they have emerged from the shell. Look carefully, perhaps with a hand lense, for the tiny, oval, brownish early stages. The Missouri Botanical Garden website suggests spraying in early May but here in Toronto, the timing would be June.
Also note that Neem is not yet on the okay-to-use pesticide list for Ontario even though you can occasionally find it on store shelves.

Pine needle scale:

http://www.missouribotanicalgarden.org/gardens-gardening/your-garden/help-for-the-home-gardener/advice-tips-resources/pests-and-problems/insects/scale/pine-needle-scale.aspx

General information on scale insects:

https://www.mortonarb.org/trees-plants/tree-and-plant-advice/help-pests/scale-insects

Ontario Pesticides Ban:

https://www.ontario.ca/page/pesticides-home-lawns-and-gardens