Calico/Lecanium Scale

[Urban Forester]

Just curious...
Has anyone (besides us) run into an intense outbreak of these 2 scale insects this year. We had entire subdivisions and bordering natural areas heavily infested with them. They seemed to come out of nowhere, with numerous species affected. Locust, Oak, Tulip Poplars, Ash (the few that are left!!!) to name a few. It seems that crawler stage is the best time for control. I was however wondering if anyone has had success with Hort. oil, and @ what %? We haven't had much luck w/soft scale control with oil as a dormant spray.

 

[alanarbor]

During the crawler stage, 2% is probably the maximum concentration that can be used that time of year. A common reccomendation is Distance (an IGR) mixed with 1% oil for crawler control. Safer soap will work well, and if the situation is extreme, most pyrethroids will work. High value trees can be preventatively treated with merit as a soil injection.