I have elderberries that Japanese Beetles seem to really relish. Insecticidal Soap did a fair performance controlling them. However they would come back fairly soon and even before the next rain. Neem Oil did a much better and longer control on them. They stayed away until the next very hard rain which is not exactly common in my part of Arkansas in the deepest throes of summer. Like the article says hand picking (Which I do) is great method, however, when you have 50 elderberry plants that can get pretty tedious. I was literally picking quarts of them a day before using Neem oil. Filling a five gallon bucket a week. In my 50+ years, my particular site here in North Central Arkansas had never seen them until three years ago.
I have elderberries that Japanese Beetles seem to really relish. Insecticidal Soap did a fair performance controlling them. However they would come back fairly soon and even before the next rain. Neem Oil did a much better and longer control on them. They stayed away until the next very hard rain which is not exactly common in my part of Arkansas in the deepest throes of summer. Like the article says hand picking (Which I do) is great method, however, when you have 50 elderberry plants that can get pretty tedious. I was literally picking quarts of them a day before using Neem oil. Filling a five gallon bucket a week. In my 50+ years, my particular site here in North Central Arkansas had never seen them until three years ago.