in peanut fields had a range of approximately 30–3600
spores per g of soil and could cause root rot disease (Horn et al.,
1995). To evaluate the minimum inoculum dose of A. niger that
caused disease on peanut, a plant experiment was conducted un-der light room conditions. Inoculation with 107
fungal spores
caused 100% disease incidence, and inoculation with lower spore
numbers reduced disease incidence (Fig. 1). A. niger infected pea-nut plants are shown in Fig. S1.