Protect Rosaceous Hosts Now From Juniper Rusts

Gymnosporangium rusts are sporulating now on Juniperus hosts.  Look for orange, gelatinous structures on foliage and stems of various Juniperus spp.  They are sporulating both in container production and in the field.  They can usually be found sporulating when the Cercis canadensis (redbud) begin to bloom, unless it is too dry (like it was in 2016).

CedarAppleRustJLA                                        Monitor for Gymnosporangium rusts such as Cedar-apple rust (above)

Ced-Haw_Juniperus2JLA                        Cedar-Hawthorn Rust (above)

Cedar-Quince_JuniperusJLA                                                  Cedar-Quince rust (above)

PearTrellisRustJuniper                                and Pear Trellis Rust (above) on Juniperus.

Their spores spread by wind and rain for several km. Protect Rosaceous hosts (e.g. Pyrus, Amelanchier, Malus, Crataegus etc.) before rain or irrigation events with fungicides such as Nova, Pristine, Daconil or Dithane.

About Jen Llewellyn

OMAFRA Nursery and Landscape Specialist @onnurserycrops
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