Gummy stem blight

What you see

Water-soaked, then tan-grey, cracked lesions on the stem near the crown, oozing an amber gum. Leaves develop pale spots with a dark border starting at the leaf edge. The vine wilts from the crown outward while the roots stay healthy.

Conditions

Warm, wet and humid. Enters through wounds - pruning scars, insect damage, or the split where a vine was trodden on. Seed-borne as well as soil-borne.

Treatment

Cut out and bin affected vines well back into clean tissue. Copper or Bacillus subtilis on the remaining plants. Do not handle vines when wet.

Prevention

Two-year rotation minimum. Buy clean seed. Avoid overhead irrigation, mulch under fruit, and avoid injuring stems when weeding or harvesting.

Months: June, July, August, September

Plants

Melon, Watermelon, Cucumber, Pumpkin, Butternut squash, Marrow / Courgette

Remedies

Bordeaux mixture (copper), Bacillus subtilis biofungicide, Mulch

The thing people get wrong

The amber gum on the stem is what tells you this is not Fusarium and not simple wilt. It also tells you how it got in: through a wound. Most gummy stem blight in a home garden traces back to a careless boot, a pruning cut made with wet secateurs, or a harvest scar - which means being tidier with the knife does more than any spray.