I've used Serenade garden pretty much according to directions but sometimes rain prevented me from spraying on the needed day. It seems to have helped a LOT since I've had a bumper crop of tomatoes this year in comparison to the last three years when I got very few tomatoes.

But now the blight has affected the bottom half of my tomato plants. I've been removing the affected leaves (but you can see I need to do it again when it stops raining) and there is a lot of healthy green at the top but the bottom half of the plant is gone. There still are a lot of tomatoes on the plants.

My question is, should I keep spraying? Will it slow the blight down? Serenade is very expensive and I don't want to keep using it if it won't help further. I've looked for some independent research on this product and found a little but not much. I'd appreciate anyone with experience in this issue.