A disease that agricultural experts say has never been seen in the United States is killing ice plant in San Diego County.
‘Downey’ mildew is impacting the red apple variety of ice plant.
“It’s a new variety of Downey mildew. We haven’t seen this strain of it before, and red apple seems to be the only thing right now that this strain is affecting. It’s just kind of melting off the vine,” said David Ross of Walter Andersen Nursery in Poway.
Ross said the diseased red apple ice plant was first noticed in Poway last June during unusual summer storms. It’s believed someone unknowingly brought back an infected plant from South Africa or New Zealand, where the disease has been previously reported.
In many areas where the red apple has previously thrived, such as Carmel Mountain along Ted Williams Parkway, the ice plant is turning brown and dying. It’s not clear if the red apple will be able to survive the disease.
Ross said in some cases, a product called Agri Fos has helped, but only under certain circumstances.
“If you have existing plant that is not melted away, I would recommend spraying it with something like Agri Fos, which should do a pretty good job of cleaning up anything that might be there, and it will probably come back,” said Ross.
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If red apple has completely died, it’s not recommended to immediately pull it out because the root systems will help retain soil that could be impacted by future El Nino rains according to Ross.
He recommends purchasing an erosion net and replanting something other than red apple. For now, he’s advising homeowners to keep the ice plant as dry as possible because the mildew has been most persistent in areas that are damp.
