Fusarium leaf spot of Dracaena

Symptoms

Reddish-brown spots with yellow halos on young Dracaena leaves, spots expand + coalesce killing entire leaves, white-to-pink sporulation visible in lesion centers under high humidity, severely affected plants lose lower leaves first then progress upward.

Easily confused with

• Pythium root rot

  How to tell them apart: Fusarium proliferatum on Dracaena fragrans shows up first as the leaves themselves: discrete reddish-brown to tan leaf spots, often with a yellow halo, starting at the leaf tip or margin and running along the blade, sometimes coalescing into dry necrotic streaks. The stem/crown rot is dry and fibrous; cutting the cane reveals reddish-brown to pinkish vascular discoloration, and in humid conditions a salmon-pink to white fungal mould may form on lesions. Roots can still look largely intact. Pythium aphanidermatum, by contrast, is a root-and-crown rot: the lower leaves go uniformly chlorotic and then wilt and droop from the base up, but you rarely see distinct spotting on the blade. Pull the plant and the roots are the giveaway — soft, brown to black, mushy and water-soaked, with the outer cortex sloughing off so the inner thread (stele) slips out when pulled. It is driven by overwatering, waterlogged or poorly drained mix and warm temperatures, and the crown stays slimy/wet rather than dry and fibrous.

• two-spotted spider mite

  How to tell them apart: Tetranychus urticae (two-spotted spider mite) produces fine, even pinprick stippling that starts on the leaf undersides of Dracaena fragrans and spreads as a sandy, silvery-bronze speckled wash; look for tiny moving dots, two dark body spots, and—diagnostically—fine silk webbing in leaf axils and along margins when populations build. Fusarium proliferatum (Fusarium leaf spot) instead makes discrete tan-to-reddish-brown spots, often water-soaked at the edge with a yellow halo, concentrated on young and emerging central leaves; spots stay fixed in place, enlarge into irregular blotches, and never produce webbing. The single clearest field test: turn the leaf over and look for webbing and moving mites (mite) versus fixed, halo-ringed necrotic spots on new growth (Fusarium).