This is the third year I've been growing basil, and this time around I decided I was going to make a lot of pesto (in addition to other fresh uses and for drying), so I have six plants in the ground and one in a container. I half expected I might have downy mildew problems again, but I was shocked when it started showing up on one of my in-ground plants about two or three weeks ago. I have gotten to late-July or August before it shows up, but this year it came quite early.
It's a horrible problem because there's nothing you can do about it. If the spores get to your plant, it's game over within a week or two unless you aggressively prune, and even then it's a losing battle. Luckily I was able to keep the one plant going for an extra week or so, and got some good pesto out of it. I'm hoping I can keep it away from my other plants, and even moved my containered plant out to the front of the house to see if the spacing and the physical barrier of the house might keep that very healthy and productive plant from contracting it as well.
So...does anyone else deal with downy mildew on their basil, either regularly or occasionally?