Peter from Austin, Tx writes
The plants are too tall to spray.
Monterey Garden Phos Systemic Fungicide is labeled to treat Red Tip Photinia and other ornamental plants, but it is not labeled to control Entomosporium, which is the usually the cause of leaf spot on photinia. For diseases listed on the product label, you can do soil drench applications: apply 1/8 tsp. per gallon of water and apply each 25 gallons of solution to an area of 100 sq. ft. Follow application with irrigation. Repeat as required. Limit of one application per month. If you have entomosporium leaf spot, then we recommend Fung-Onil Fungicide Concentrate instead. This should be applied as a topical spray. Be sure you are incorporating good sanitation practices as well, including cleaning up leaf litter, thinning out branches as needed to reduce moisture retention, and removing heavily infested plants. Do not plant infested photinia in your landscape. Be sure to clean pruning equipment after each use to avoid spreading diseases.
Answer last updated on: 04/21/2018
