Lower stem of a symptomatic plant. Fungal growth on the outside of the lower stem is not from the causal agent.

Stem split to see decay of pith tissue of the lower stem.

Close-up of infected pith tissue with disking similar to that seen with Black shank of tobacco.

Stem split to see decay of pith tissue of the lower stem.

Pith tissue incubated in water induces formation of a sporangium. This one is empty of spores.

Pith tissue incubated in water induces formation of several sporangium.

Mycelium of Phytophthora dreschleri in culture.

Swollen, lobed, sporangia of Phytophthora dreschleri in culture.

Two sporangia where a new sporangium is growing up through the remains of an older, empty sporangium.

A new hyphal structure growing from below the base of an older, empty sporangium.

A sporangium before it has released its spores.

Zoospores just in the process of releasing from a sporangium.

Zoospores swimming away from the sporangium.

Zoospores released from the sporangium with two remaining in the sporangium.

Zoospores beginning to move away from the vicinity of the sporangium.