canola

[tom]

We are seeing more than usual incidences of purple plants in our canola fields - quite normal growth other than plant colour and seed set in pods is less than normal pods( pods same size, doesn't look like Sulphur def. ) Some plants show more purple on the 'sunny' side of the plant/pods. Any ideas?

[mhartman]

I am also seeing purple colored canola, but otherwise normal plants. The purple color is due to a pigment called anthocyanin, which becomes visible when the normal green pigment chlorophyll is reduced in proportion. Stress conditions tend to upset the proportional balance between the pigments. Such stresses can be nutritional (sulphur), or temperature, etc. Also, canola varieties differ in their anthocyanin levels. So the purple color can be related to genetics, environment and nutrition. But if the plant is podded and filling normally, there is nothing to worry about!

[rdowbenk]

I had seen this last year and the previous year. As Murray stated - despite the visual impact - things were normal. I tend to think it was similar to sunscald, as the canola that had highest incident sunlight, tended to show the redness/sunburn. Some fields had plants that were affected only on one side. I checked with Phil Thomas, and agreement was reached, as sunlight being the most likely cause.

[jim]

I was swathing some canola that has some of the purple color on the south side of the plants too. However the pods were not filled and the plants had a twist to the stem. This crop had been hailed this summer. Could this stress also cause this to happen?

[mhartman]

It is possible that hail damaged canola could show more purpling later on. However, your observation of twisted stems and poor pod fill suggests to me that there might have been some herbicide damage. Phenoxies like 2,4-D and MCPA cause stem twisting. Check into the possibility of drift where the worst damage is on one side of the field.

[jim]

I don't think there is a herbicide problem regarding drift. The purple plants are in various places in 2 small fields. There is also some plants in an adjoining pea field that was sprayed with Odessy where volunteer canola was missed in the corner. The canola only had Edge applied last fall.The previous bly crop was sprayed with Assert, Refine, and then Round-up as pre-harvest.The leaves on the affected plants are green and look ok.