I looked it up in my Organic Method Primer UPDATE:
1. Fungal mycelium can be dehydrated by talcum powder or diatomaceous
2. A very dilute spray of insecticidal soap can be sprayed on foliage.
3. Rhubarb LEAVES: make a water extract for spraying the crop foliage.
It may be helpful, for the future, to know there are ways to help PREVENT
1.Baking soda solution as spray on leaves: .25 oz per gallon of water
OR: 7 tbsp in 5 gal water, plus a few drops of insecticidal soap,
2. Soybean lecithin dissolved in 80% ethyl alcohol, diluted with water.
3. Compost tea sprayed on the plant, before infection.
4. Maybe helped by flour paste dissolved in enough water for spraying.