Whiptail

What you see

New leaves come up narrow, strap-like and puckered, with the blade tissue between the veins simply missing - reduced to a whip of midrib. Cauliflower curds fail to form properly.

Conditions

Acid soil, below about pH 5.5, which locks molybdenum out of reach even when it is present. Sandy, heavily leached ground is most at risk.

Treatment

Lime the bed to raise pH toward 6.5-7.0 - that alone usually fixes it, because the molybdenum is already there. A seaweed foliar feed helps the current crop through.

Prevention

Test soil pH before sowing brassicas and lime in autumn so it has time to work. Brassicas want a sweeter soil than most vegetables.

Months: March, April, May, September, October

Plants

Cauliflower, Broccoli, Cabbage, Curly kale, Brussels sprouts

Remedies

Seaweed extract

The thing people get wrong

This is misread as virus damage or herbicide drift almost every time, and the plant gets pulled. It is a soil chemistry problem, not a pathogen: molybdenum becomes unavailable below pH 5.5. What makes it worth knowing is that the same acid soil is what clubroot loves - so if you have whiptail, you are also growing the perfect conditions for a far worse disease, and liming fixes both.