|I had originally thought this to be "black leg", a mould to which Cole veggies (Broccoli, Cauliflower, Brussels Sprouts) are susceptible. This specimen is on my Broccoli.|
However, when I crop the image and view it close up, the grey "crystals" appear to be bugs.
My solution to this infestation, was to remove the infected plants if they were stunted, or to remove the affected leaves, if the plant appeared otherwise vigorous. I gather that most issues with Cole varieties arise due to their size, vigour, and growing too close together. AND over-head watering. My two beds suffered from all this. They looked wonderful until last week when they appeared to "sag", a bit like Alannah when she droops her shoulders to signify unhappiness.