Powdery mildew has been a major challenge for California growers this year. In fact, according to Tim Ksander, technical manager for FMC, it’s one of the worst these growers have ever encountered.

Powdery mildew is an interesting disease, Ksander told AgWired during the recent 2016 CAPCA Conference & Agri-Expo, because the disease infests numerous crops. However, there are different genera and they attack plants in slightly different ways.

Fortunately there is a solution for growers from FMC called Rhyme™ fungicide, which Ksander said works on virtually all the different genera. One crop in particular that has been hard hit is grapes. “First powdery mildew infects the leaves and eventually it gets into the fruit, and that’s the part we’re trying to protect,” said Ksander. “The advantage of Rhyme fungicide is that it is systemic and can be sprayed right on the leaves. It can also go into the soil and can be taken up by the root system.”

Ksander said that whenever a grower is working with fungicides, he needs to be aware of resistance issues. A component of a good resistance management plan includes the timing of fungicide applications. “The best time to apply a fungicide is preventative because when a disease starts it’s harder to get rid of it. Rhyme fungicide has some curative activity so if there is a little bit of it there it will knock that back and prevent it from sporulating. Preventative treatment is the key to successful disease management,” stressed Ksander.

“To manage resistance what needs to be done with all fungicides is rotation, rotation, rotation. Rotation is the number one key to successful resistance management,” Ksander added. Another key? Mixing up modes of action.

Fungicides should be rotated within the growing season and between seasons. He explained, “If you end the season with a material such as a triozole, you don’t want to start the next season with that because that disease organism has already been subjected to that. Rather you want to start with a different mode of action when you start the season then rotate to another mode of action.”

To learn more listen to my interview with Tim Ksander here: Interview with Tim Ksander, FMC

Be sure to check out all the action by viewing the 42nd Annual CAPCA Photo Album.

Legal: Always read and follow label directions. Shark EW herbicide is only registered for use in California. FMC Fracture, Koverall, Rhyme, Shark and Sovran are trademarks and Investing in farming’s future is a service mark of FMC Corporation or an affiliate. ©2016 FMC Corporation. All rights reserved. 16-FMC-0857, 10/16