Common Name

Spots

Scientific Name

Alternaria, Ascollhyth, Cerospora, Septonia, Collectrichum, Gleosporium, Phyllosticta.

Physical Description

Thousands of fungi, bacteria, viruses cause spots and discoloration. Not usually serious. Fungi cause black spots on lesions. May be mistaken for chemical spray, frost, wind particle damage, pollution.

Life Cycle

Fungi may enter through the soil. Others may be airborne or brought by insects. Is usually arrested by plants defence mechanisms. Ill plants will repond to attack.

Damage Caused

Attacks living cells and veins. Wilting, decay, death.

Control methods

Many do not require treatment, impractical. Ornamentals can be sprayed two or three times a forghtinght with thiram or benomyl. Maintain hygenic conditions. Do not harm or damage bulbs. Treat well in storage. Burn infected plants.