What a watermelon grower does with in the next 24 hours from this blog post could be beneficial for watermelon production and disease management. I would encourage you to follow my thought process below as I look at the importance of three factors this week and then determine what I think it all means.
Disease Reports from Northern Florida
Over the weekend, downy mildew was reported in northern Florida in cucumber. There are 5 pathotypes of downy mildew that affect cucurbits. All of them go to cucumber. This means that we still could have some time before the pathotype that affects watermelon shows up, however, we do not know if the one reported goes to watermelon or not. Also, cucurbit downy mildew starts out in Florida and moves up the east coast in storm systems.
Wet and Cool Conditions for the Week
We have several days that show good chances of rain for the week. Temperatures after this are going to cool down some as well. It is important to note the direction of the rainfall headed to Georgia. It is all coming up out of South Florida.
Fruit Set and Fruit Size
I have observed fruit in the field up to and a little larger than softball size. If a grower is using Orondis in his fungicide program for phytophthora, the softball sized fruit stage would be an optimal time to apply it. Also this softball sized fruit stage is when we stop using Chlorothalonil to avoid rind burn.
WHAT IS WILL GAY TRYING TO TELL YA???
Since there is inoculum present in north Florida, and there is a large storm system sweeping across the whole state of Florida before reaching us, there is a chance that downy mildew inoculum could spread to our area. We had downy mildew last year in multiple fields and the inoculum came from a similar storm system but it was a little later in the season. There are a few options that we have for treatment. If you would like to make a fungicide application for phytophthora and you have softball sized fruit, you could apply orondis and also get protection of downy mildew at the same time. If you are just starting to flower or set fruit, or do not want to treat for phytophthora, there are some other options to consider also. Feel free to contact me at 229-313-4147. I have spray schedules for this disease, however, we may be able to use a preventive fungicide now, and evaluate later on for the spread of this disease to determine which way to go for future sprays.
