What weather condition causes millerandage?

• A. Cold, wet, windy weather at pollination and fruit set.
• B. Hot dry weather at veraison.
• C. Excess nitrogen.
• D. Drought.

Answer: (A)

Millerandage is caused by problems with pollination during flowering. Cold, wet, and windy weather at this critical stage reduces pollen viability, pollen transfer, and stigma receptivity, so many flowers fail to fertilize. The result is a cluster with many tiny, undersized berries mixed with normal ones—the classic “hen and chicks” appearance.

The other conditions don’t target the flowering pollination process: hot, dry weather at veraison affects ripening and color development; drought stresses water status; excess nitrogen influences vigor but doesn’t directly cause failed fertilization during flowering.