Fourteen peanut genotypes (Arachis hypogaea) were evaluated for resistance to Aspergillus parasiticus infection in 1983 and 1984 in rain-shaded field microplots where water stress conditions were simulated, and in unshaded microplots under normal rainfall conditions. A brown color mutant of A. parasiticus (ATCC 24690) was grown on cracked corn and the colonized corn was spread on the soil in each microplot. Soil moisture and soil and air temperature were monitored. Infection of peanut pegs, pods, kernels and tap and fibrous roots was enhanced by low soil moisture. Infection of kernels differed among genotypes; all other tissues were found to be infected at moderate to high frequency and no genotype differences were observed. Genotypes J-11 and Lampang were characterized as resistant to A. parasiticus under both dry (1983) and moist (1984) field conditions. Although percentage infection of kernels varied with genotype, ranking of genotypes reported to have drought resistance was consistent under both dry and moist field conditions. Thirty-four peanut genotypes, including those tested in field microplots, were also evaluated for dry seed resistance to A. parasiticus infection in the laboratory. Genotype J-11 and PI 337409 were highly resistant. Except for J-11, there was no correlation between genotype rankings for resistance to dry seed infection and resistance under field conditions.

Groundnut is an important food and cash crop in the Southern African Development Community (SADC ) region, and is grown largely by smallholder farmers under low input conditions. Constraints are many and varied, both between and within the member states, but diseases are generally regarded as major constraints to groundnut production throughout the region. A large number of fungal, viral, nematode, and bacterial diseases of groundnut have been reported. Most of the diseases are widespread, but only a few of them are economically important on a regional basis. In this paper, the current distribution and economic importance of leaf spots, web blotch, rust, gray mould, pod rots, blackhull, Sclerotinia blight, stem rot, seedling diseases, aflatoxin contamination, rosette, groundnut streak necrosis, pod nematode, and pod scab nematode diseases, and various options (chemical control, host-plant resistance and cultural practices) for their management, are briefly reviewed. Future research needs on groundnut diseases in the region are discussed.

Isolations from groundnut kernels in Malawi showed Aspergillus niger, A. flavus, Mucorales, Macrophornina phaseolina, Fusariurn spp. and Penicilliurn spp. t o be the most common members of the fungal flora. In the laboratory a seeddressing containing thiram had a strong inhibiting effect on the kernel flora with the exception of A. flavus, although it was able t o afford some protection t o healthy kernels against A. flavus attack in soil in test tubes. When grown individually in plate cultures the most commonly isolated fungi were generally only slightly inhibited by thiram in the agar. Field trials over three seasons showed that dressing the seed with fungicide had little effect on yield and this practice is thus not generally recommended.