Field Update – 5/20/19

Statewide: Dr. Guido Schnabel reports, “Green fruit rot is starting to show up in commercial peach orchards. This disease is caused by the fungus Monilinia fructicola. In spring we had an extended period of bloom with lots of rain. That led to blossom blight caused by the same fungal pathogen. Growers must take this disease very seriously as it can cause significant preharvest and postharvest fruit rot. Many take advantage of our lab service to determine potential weaknesses in fungicide spray programs. For more information contact your local county agent or Dr. Schnabel directly at schnabe@clemson.edu.”

Green fruit(Monolinia fructicola) rot on a peach. Photo from Dr. Guido Schnabel.

Coast: Zack Snipes reports, “We have had nice warm weather that is helping the development of irrigated crops.  We are starting to get dry and could use some rain for dry land crops and to settle dust. We are in the middle of squash and cucumber harvest.  We are starting to see powdery mildew show up on cucurbit crops. The tomato crop looks promising this year despite the usual bacterial wilt common in fields.  To test for bacterial wilt, select a wilting plant, cut it through the stem, and put into a jar of water.  If the pathogen responsible for bacterial wilt is present (Ralstonia solanacearum), you will get what’s known as bacterial streaming which is a milky white stream coming from the cut end of the plant.

Bacterial wilt ( Ralstonia solanacearum) on tomato. Photo from Zack Snipes
Powdery mildew on squash leaf. Photo from Zack Snipes.

Midlands: Justin Ballew reports, “The weather this past week was pretty mild, but dry. Thrips have become a problem in strawberries in some areas, but we are so close to the end of picking that most growers would not benefit from a treatment. Production has really decreased and some growers have already begun redirecting picking labor to other crops. Spring planted squash and peppers are starting to come into production and everything is looking pretty good. Keep an eye out for spider mites on tomatoes as it gets hot and stays dry this week.

Thrips damage on developing strawberry.
Peppers are developing well in the midlands. Photo from Justin Ballew

Sarah Scott reports, “We have begun picking early varieties of peaches across the Ridge. Things are looking good for a nice crop this year. Green fruit rot (Monilinia fructicola), also known as brown rot, has shown up in a few spots around the Ridge. We are continuing to monitor stink bug populations in orchards. Traps have shown high numbers of insects but damage has been scattered in this area.

Peaches are looking great on the Ridge. Photo from Sarah Scott.
Stink bug trap on the edge of a peach orchard. Photo from Sarah Scott.

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