Cedar-apple Rust - La rouille de genévrier

            This is an amazing creature - a fungus/rust that in the form shown has Red Cedar as its host. In Ontario, it is unique to the Ottawa Valley and south, in Quinte, because of the abundance of Red Cedars. During my backroading a few weeks ago I came across it and became fascinated with it. 

For context: this is about the size of a baseball. 

The fungus has multiple life forms, which appear in alternating years, and each of which requires a different host. The fungus cannot transmit from Red Cedar to Red Cedar, nor can it appear annually. 

The pictured form begins in late fall as the brown gall, which contains mycelium. In the spring, especially around water, it sprouts the orange tentacles, called telial horns. They emit teliaspores only during rainfall, and the spores travel to apple trees and infect them only after the petals have fallen from the apple flowers. And the infection only happens during rainfall, through water transmission into the apple tree. 

The spores can travel 6-8 kilometres (3-5 miles), but are more likely to be effective in close range. When it is not wet from rain, the horns dry out and contract. A few hours after I secured this image, the orange horns were dried out and dark brown. 

In late summer, the spores form clusters on the apple leaves and on the fruit itself. In the fall they in turn release different spores that form small green clusters on the Cedars, and the following spring, green galls form on the Cedars - but only in the spring a year later do the Green galls turn brown, and emit the horns etc.

Taken on: May 3, 2021

Tags:

Alternating hosts

Fungus

Apple

Red Cedar

La rouille de genévrier

Cedar-apple Rust « less

Groups appears in: • Awesome Nature • *amazing nature* more » • Mushrooms and Fungi • Nature...Anything Goes • National Geographic Wild Life • Nature Canada • in explore « less

Camera: Canon EOS 80D, f/6.3, 1/640 sec, 400mm, ISO 2500 (more info) (hide info)

Camera:	Canon EOS 80D
Lens:	EF100-400mm f/4.5-5.6L IS II USM
Aperture:	f/6.3
Exposure Time:	0.002 sec (1/640)
Focal Length:	400mm
ISO:	2500
Exposure Bias:	0 EV
Flash:	Off, Did not fire
Exposure Program:	Aperture-priority AE
Exposure Mode:	Auto
Metering Mode:	Spot
White Balance:	Auto
Color Space:	sRGB
Software:	Adobe Lightroom 4.2 (Macintosh)
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