Why Are My Pea Plants Suddenly Wilting and Dying?

Pea plants that appeared healthy — growing well, flowering, developing pods — and then abruptly wilt over a few days and collapse without recovering, particularly in warm weather, almost certainly have fusarium wilt (Fusarium oxysporum f. sp. pisi) or a closely related vascular disease. The collapse can look like drought wilt, but the plant does not recover when watered. The roots and stem base show characteristic discolouration that confirms a vascular pathogen.

How to confirm fusarium wilt

Pull up a wilting plant and examine the roots and stem base. Cut the stem lengthwise at the base — healthy pea vascular tissue is cream-white; fusarium-infected tissue shows a brown to orange-brown discolouration running through the vascular ring (the xylem). This internal browning, combined with the collapse that does not respond to watering, confirms the diagnosis. The roots may also be brown and sparse. Fusarium oxysporum f. sp. pisi is host-specific to peas and closely related legumes and does not affect other crops.

Why rotation prevents it

Fusarium persists in soil as thick-walled resting spores (chlamydospores) that can survive for many years without a host. Growing peas in the same ground year after year builds up soil populations to levels that cause near-total crop failure. Moving peas to a different area each year — a minimum four-year rotation — allows the population to decline between crops. In small gardens where true four-year rotation is difficult, use raised beds with fresh compost for peas in years when the main ground cannot be used, or choose resistant varieties where available.

Warm soil accelerates the disease

Fusarium wilt is most damaging in warm soil (above 18°C). Early-sown peas that crop before midsummer may escape significant damage because soil temperatures remain lower during the growing period. Late-sown peas in warm summer soil are at much higher risk if fusarium is present. This is another reason to favour early sowings (March–April) over late ones (June) where fusarium wilt is a known problem.