How to make an accurate diagnosis

The challenge is that one symptom can have many causes, so keep an open mind. Don’t have a pre-conceived notion of what the problem is. If you get a second opinion – which is a great idea – try not to convince that person what you think the problem is before that person has a chance to assess the facts.

Perspective is also important: An issue confined to a few plants in a corner of the field may not be worth the management effort.

Canola Watch had an article around this time in 2018. It discussed whether symptoms were the result of blackleg, foot rot or cutworms. Pinched or otherwise damaged-looking stems can occur with all three.

A week later Canola Watch ran another article suggesting that root issues could also be root maggots or clubroot.

This quiz provides a few demonstrations of similar symptoms, especially for purple discolouration, for different causes, .

Tests are available to help solve many different mysteries. Before collecting and submitting samples, ask the labs for their sampling, packing and delivery protocols.

Dig deeper

• How to use tissue tests for nutrient deficiency diagnosis
• Various potential reasons for missing plants
• Photo tips for agronomy. Good way to get second opinions.