Alternaria alternata

Mycology: saprophytic mould.; opportunistic pathogen, causing leaf spot, rots and blights on over 380 host species of plants, especially tomato; it causes cankers in the stem, blighting of the leaves, yellowing, browning and necrosis of the lower leaves; it resides in seeds and seedlings, is spread by airborne spores; salicylic acid, ethylene and jasmonic acid can diminish the susceptibility of tomato to the fungus; requires moisture, but survives dry conditions.
Medicinal: causes upper respiratory tract infections, asthma in humans, allergic, < reduced immunity; chronic sinusitis, maxillaris.