Factor: Plant stress

Mold can infect groundnut near the end of the growing season, a few weeks before harvest. Since strong crops have some ability to thwart infection, threats to the plant and nuts can make them more susceptible to mold and increased aflatoxin contamination.

Soil infertility, particularly insufficient calcium, which the plant needs for seed development, can make the nuts vulnerable. Weed pressure, insect damage or disease, such as leaf spot, leaf rust or rosette virus, can make infection more likely.

Drought is the most important condition that promotes Aspergillus infection.

If the groundnut plant is growing without severe stress, it is much more likely to fight off the infection from Aspergillus and show a reduced level of aflatoxin.