Aspergillus flavus, the mold that produces aflatoxin, occurs naturally in almost all soils worldwide, which makes groundnuts particularly susceptible since the nut grows underground. A. flavus can infect crops growing in most any climate, but is a particular problem in hot, humid places.
Since the spores for A. flavus are ubiquitous, it is important to minimize the conditions that promote infection and growth of the mold in groundnut, such as:
- In the field, near the end of the growing season, especially when plants are water-stressed
- In the field, when harvest is delayed
- After harvest, when nuts are not sufficiently dried or dried on bare ground
- In storage, when humidity and heat fluctuate, and the crop is unprotected from pests
- At shelling, when pods are re-wet to make shelling easier