I have a 5' magnolia ("sue") heavily infested with scale. I would prefer not to use chemical control. I am prepared to spray as often as necessary with horticultural oil - but what is the timing? Can I actually see the "crawlers"? Does it do any good to scrape them off (very satisfying)? There's a lot of advice on line, but I need information specific to Kalamazoo. thank you.
Kalamazoo County Michigan magnolia scale
Timing of horticultural oil sprays is dependent on growing degree days. The Enviro-weather website takes out the guesswork giving you emergence dates. See https://enviroweather.msu.edu/run.php?stn=kzo&mod=l_mli&da1=2&mo1=9&da2=2&mo2=9&... and scroll down to magnolia scale and you will see that the crawlers is Kalamazoo have already emerged on August 20-21. You can scrape them off; however, the female (the big bump) dies after the crawlers emerge. The crawlers are small but you should be able to see them. A 10X magnifying glass may help. Check out the following information:
thank you for your response. I don't see anything with a magnifying glass, but that could be a user error. Do you recommend hort oil spraying? If so, today and how often? (And in March, as indicated.) The scales are "wet" inside, if that's meaningful. What can I do for the plant itself to help it overcome this onslaught? Any ideas you have are appreciated.