What's Going on With Basil?
Ugghh. Another plant disease that’s here to stay is affecting one of the most heavily used and most loved herbs – the star of the summer – Basil.
This pathogen showed up in California and the Midwest several years ago and has spread to every state, leaving a trail of frustrated basil gardeners and enthusiasts in its wake. This mildew takes no prisoners, and kills every plant it infects. There are no organic fungicides that will protect your basil plants sufficiently, so being observant is the best defense. If you spot any of the classic symptoms, (yellow lower leaves and wilting) pull up the plant and make pesto with the healthy leaves. The spores are not dangerous for us to ingest, so eating the basil fresh is fine, too. But to preserve it, make pesto and freeze it for later on.
Basil downy mildew travels in a couple ways – infected seed is a primary cause, but the spores travel on the wind too. If your basil plants succumb to mildew, plant in a different spot next year, as the spores can live over in the soil. All the Genovese varieties seem to be equally affected, but the lemon type (Ocimum x citriodorum) seems to be a lot more resistant.