Scala Fungicide No Longer Viable Option on Botrytis for Vidalia Onion Producers

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By Clint Thompson

Vidalia onion producers should be wary that Scala fungicide appears to not be   effective anymore on botrytis, an important disease that growers contend with every season. That also has an indirect impact on Luna Tranquility’s impact since it partially contains Scala.

Scala fungicide

Bhabesh Dutta, University of Georgia Extension vegetable plant pathologist, discussed the disease and options available for growers.

“The general trend is suggesting that Scala has lost its efficacy. Although we have not confirmed it in the lab, based on field observations and fungicide trials, it seems Scala is losing (its efficacy). Part of Luna Tranquility is Scala, so a lot of pressure and a lot of heavy lifting is done by Luna. Part of resistance management, we should think of mixing Luna with something else,” Dutta said.

“Luna Flex may have a fit. Flex is a different fungicide group. Based on my data, although it’s one year of assessment, it’s showed it is as good as tranquility.”

Botrytis Leaf Blight infects onion foliage. Initial symptoms include white, necrotic spots surrounded by pale halos. Leaves with severe symptoms may lead to reduced bulb size.