B P International

The benthic zone of Lake Malombe was sampled for invertebrates, fungi and bacteria using an Ekman Grab measuring 15.2 cm by 15.2 cm. Thirty-six stations were surveyed for macro-invertebrates which were identified to the lowest taxa and enumerated to estimate abundance for the lake. The biomass of macro-fauna is being reported here for the first time and coincides with a decline in fish catches on Lake Malombe. Snails were the most dominant macro fauna, belonging to four genera Melanoides, Bellamya, Bulinus and Lanistes with the mean densities of 177.5, 34.7 and 4.3 and 0.1 m-2 individuals, respectively. Blood worms and Tubifex were also present. Although there are few such studies in Malawi, it was generally postulated that dominance of snails is a recent phenomenon following previous studies which showed the invasion of a form of Melanoides of Asian origin; its success might be responsible for its proliferation. The benthic substrate was mainly composed of mud, clay granules, sand ...

Tomato is one of the most widely grown and extensively consumed horticultural crops in the world. Isolation, identification and pathogenicity of fungal organisms causing postharvest spoilage of tomato fruits during storage was carried out. Tomato fruits showing symptoms of rot were collected from the store house. Small sizes were cut and surface sterilized in 1% of Sodium hydrochloride and rinsed in several changes of sterile distilled water. They were plated on Potato Dextrose Agar (PDA) and observed for fungal growth. Identification was done macroscopically and microscopically. For pathogenicity, healthy tomato fruits were plugged with pure cultures of the fungal isolates and disease incidence and severity were evaluated. Five fungi namely Aspergillus flavus, Penicillium waksmanii, Botryodiplodia theobromae, Fusarium oxysporum and Colletotrichum asianum were isolated. Incidence of decay on healthy tomato fruits was 100% for all fungal isolates while the control was 0%. T-test reve...