It's important for my readers to know that many of the things I talk about in these pages were learned by trial and error; a lot of errors!
For example, in a non-rosy matter this summer, I asked a commercial sprayer, who was spraying fungicide on my neighbor's flowering crabs, to also spray my Harrelson-Red apple tree. He told me he was spraying a systemic and stated the chemical name which sounded vaguely familiar, but it didn't register with me and I didn't check it out. Unfortunately, I later found out that what he sprayed was the systemic fungicide Banner-Maxx, which I use as a systemic blackspot inhibitor on my roses, along with Manzate. Banner-Maxx is labeled only for fruit trees that will not be used for human consumption and there are now hundreds of beautiful apples on that tree that I will have to throw away this fall. I really should have known better, but I won't make that mistake again, for sure. To make matters worse, that boner cost me ten bucks!
I also just learned something else in the last week about my roses, which have been absolutely beautiful all summer. I started seeing lots of shiny leaves, like something sticky had been sprayed on the plants. After a little checking around, I discovered that what I was seeing was "honeydew", the sticky excretion of thousands of aphids that had infested several of my beds. I haven't seen aphids in any quantity in my beds for years and that really started me scratching my head. I have always cultivated beneficial wasps and flies in my gardens that feast on a variety of insects, especially aphids, so what changed? Where did the beneficials go and why this infestation? I immediately water-washed the plants with my bug blaster and sprayed with insecticidal soap, and then with a combination of apple cider vinegar and Castile soap, which killed a bunch of aphids, but not nearly enough to keep up with the supply that was attacking my plants. After a few days the plants were looking really stressed and today I cut off lots of new growth that was starting to die back. Tomorrow, I will be spraying with imidacloprid, which I know will take them down immediately, but I really hadn't wanted to do that this year, because of its potential effect on bees
I immediately suspected that I had made another foolish mistake and I read everything I could find on the internet about aphid infestations. What I discovered is that by over-spraying certain insecticides, such as acephates (like Orthene)and pyrethroids (like Demand CS) you can kill off all the beneficial insects, which then gives rise to aphid infestation. And I really had no idea what aphids would do to the roses, once they are uncontrolled by beneficial insects.
Those of you who have followed my blogs for the last year or so know that I have been successfully experimenting with the pyrethroid Lambda Cyhalothrin (Demand CS) for controlling Japanese Beetles. Since it is also labelled for spider mites, I thought that I could make it do double duty with both spider mites and JBs. Mistake! I ended up overusing it this summer and, to make matters worse, since it is labeled for aphids, I used it again to try and wipe out the aphid infestation, which failed completely and the infestation just got worse.
So by making this seemingly foolish mistake, I have learned the limitations of overusing a pyrethroid, which has a very important application in controlling JBs and which I want to be able to use in the future. The lesson is to use it very sparingly and only when a true JB infestation occurs, which we really haven't seen this summer. (Picking the beetles by hand and drowning them in soapy water is still the preferable way to control JBs and I must admit I just got lazy on that front this summer, in favor of spraying Demand CS, which works so well.
The other thing I learned is that the combination of Castile soap and apple cider Vinegar controls aphids, although not enough to forestall an infestation. I had given up on it earlier this summer when it didn't work on thrips but, since I wasn't seeing aphids at that time, I didn't realize that it was working to hold them down. I will definitely return to this very benign approach toward aphid control, as soon as I achieve a "knock-down" to save my beds. Here's my post on Castile soap:
So, another valuable lesson learned. But remember that if you aren't trying new things and, yes, making a few mistakes, you will never learn how things should best be done. In that regard, you can make an educated guess that many of the things I discuss in these pages have been learned and perfected by making mistakes.