QUIZ – Sclerotinia stem rot

Three questions on sclerotinia stem rot management – specifically on assessing the moisture situation and what to do with uneven crops.

1. With ample moisture, apothecia are germinating and shooting their sclerotinia spores into the air. While we have no known threshold for rainfall required for spores to infect, AAFC plant pathologist Kelly Turkington provides this rough guide to describe the moisture required for infection: Rainfall (at least 5-10mm) more than two days a week and daily minimum relative humidity (RH) over ___ per cent.

60

70

80

90

2. A canola crop with uneven staging presents a challenge for fungicide timing. Which of the following would be the most accurate agronomy statement for fungicide timing on an uneven crop?

Consider spraying when the earliest plants are at the right stage because early infections usually cause the most yield loss.

Uneven crops are too much of a bother. Just ignore them.

Consider spraying when the latest plants are at full flower as this will provide a curative response for the greatest number of plants.

Uneven crops should be sprayed twice because a single application timing is too hard to judge.

3. How does hot and dry weather during and after flowering change the sclerotinia stem rot risk scenario?

Increases the risk

No change

Decreases the risk

 Loading...