It’s that time of year again where you have to make a choice with your poinsettia. Do you stay the course with natural enemies, or abandon your bio program and spray for whitefly? And spray with WHAT?
This post has tips on how to test pesticides NOW, so that when it comes down to the wire, you’ll know what is – and isn’t – working.
The Critical “Tipping Point” In Poinsettia:
Some of you may be familiar with the “whitefly tipping point” I’ve referred to in several blog posts and articles (see this issue of Greenhouse Canada Magazine). Essentially, this is when growers have to decide whether or not to switch to chemicals for whitefly control, so they can end up with a clean crop. Switching to pesticides later than the last week of September/first week of October may mean you don’t have time to get on top of your whitefly population if repeated applications are needed.
What’s Up with Whitefly in 2020?
This year has been a real mixed bag. Some people have little whitefly pressure. Others had very high starting populations, e.g. up to 60% plants infested with whitefly in August, even WITH dipping cuttings. This variation seemed to be within the same suppliers, but cuttings may have come from different source farms.