Pepper spot and scorch

Infected leaves
Pepper spot looks sooty
Cause

Leptosphaerulina arachidicola

Damage

Minor but widespread. Leaves drop off. Is often one of the earliest foliar diseases to infect crops.

Symptoms

The same fungus causes two different symptoms under different weather conditions. Pepper spot occurs when very small spots, under 1 mm, develop on the top of the leaf. Scorch occurs when a V-shaped part of the leaf dies (usually on the margin) and a yellow zone forms next to it.

Spread

The fungus survives on peanut residues and is spread by wind.

Management options

Chemical
The fungicides used for controlling the other foliage diseases usually control this organism. Use a protectant fungicide if no other disease influences the choice.

Cultural
These diseases are not normally serious in traditional production areas using the current varieties.

Chemical registrations and permits
Check the Australian Pesticides and Veterinary Medicines Authority chemical database and permit database for chemicals registered or approved under permit to treat this disease on the target crop in your state or location. Always read the label and observe withholding periods.