From Clemson Fruit Pathologist Dr. Guido Schnabel and UGA Fruit Pathologist Dr. Phil Brannen.
Unfortunately, there appears to be a shortage of Captan products this year. For our fruit crop producers this may result in a change of strategy if and when reserves run out. Strawberry growers fortunately have the option to use Thiram for basic gray mold and anthracnose control. The two products are basically equal in efficacy but thiram has a slight edge over captan for gray mold control, but it is a bit weaker against anthracnose.
Peach growers rely on captan for cover sprays. These early to mid-season applications manage green fruit rot and possibly anthracnose. Fortunately, during bloom and preharvest we use different chemistries at our disposal listed in the spray guide. As we mention often, we prefer to hold other chemical classes, those for which Monilinia fructicola (brown rot) is most likely to develop resistance, for use in the pre-harvest sprays. During captan shortage, we recommend application of two applications of a QoI/SDHI (FRAC 7+11) product, such as Luna Sensation, Merivon, Pristine or Quadris Top (FRAC 3+11), for cover sprays as needed this year. Along with any remaining captan products, we hope that this will help us to limp along till next year, while still providing excellent control of cover spray pathogens. Sulfur alone in cover sprays, though sufficient for scab control, is not efficacious for green fruit rot or other diseases; if using a QoI/SDHI (7+11) product, these will control scab as well as green fruit rot, so sulfur would not be necessary for these applications. As always, please contact your local extension agent should you have questions.
Don’t forget to check out the Upcoming Meetings page for all the meetings coming up over the next couple months. There are 2 coming up this week: Strawberry Fertility Wednesday (2/17) and Produce Safety Rule Training on Thursday and Friday afternoon (2/18 and 2/19). We hope to see you there!
Zack Snipes reports, “I haven’t been out in the fields lately due to all of the rain. Hopefully it will dry out some this week as we really need some bluebird sky days. If and when you are able to get out in the strawberry fields, it is time to put out boron. Boron helps with flower and fruit development. If you miss this application you will have lots of “bull nose” fruit in a few weeks. We recommend 1/8 lb of actual boron. Please see the picture for calculations of different products. Be extremely careful with mixing, calibrating, and applying boron as boron is a great herbicide if overapplied. Boron can be sprayed or run through the drip system.
Justin Ballew reports, “It’s been raining a lot since Thursday (2/11) here in the midlands. The soil is saturated in some of the less sandy areas and it will be a while before fields are dry enough to work. Sandier areas likely won’t be delayed much. Before the rain came, folks were harvesting some nice looking greens, though I am seeing some disease pop up in places. Strawberries are still coming along. I know of one fairly large grower that has already started protecting blooms. More will probably start soon.”
Sarah Scott reports, “It has been extremely wet throughout Aiken and Edgefield Counties the past week, making field work challenging. In peach orchards, we are continuing to prune and trying to get out dormant oil applications and copper. It appears there is a shortage of Captan this year. There are alternatives for use during bloom as well as at petal fall, just something to look into if you usually use this product. You can read about some alternatives here https://site.extension.uga.edu/peaches/2021/02/captan-shortage/ . Again, it looks like we will have plenty of chill hours for the crop this year with Musser Farm sitting at over 1000 and around 950 hours in Johnston.”