This paper presents a preliminary report of Fusarium wilt of Roselle in the Nigerian savanna. Soil and plant samples were collected from eight experimental plots where plants showed Roselle wilt symptoms. Samples were analyzed for the presence of nematodes and wilt pathogens. The wilt causative organism Fusarium oxysporum was isolated together with nematodes of different genera. However, nematodes of the genus Helicotylenchus, Scutellonema and Hoplolaimus appeared to occur in higher densities than the others.
The paper deals with the effect of heating of various prepared batch materials into semisolid state with subsequent solidification of the cast under pressure. The investigated material was a subeutectic aluminium alloy AlSi7Mg0.3. The heating temperature to the semisolid was chosen at 50% liquid phase. The used material was prepared in a variety of ways: heat treatment, inoculation and by squeeze casting. Also the influence of the initial state of material on inheritance of mechanical properties and microstructure was observed. The pressure was 100 MPa. Effect on the resulting casting structure, alpha phase distribution and eutectic silicon was observed. By using semisolid squeeze casting process the mechanical properties and microstructures of the casts has changed. The final microstructure of the casts is very similar to the microstructure that can be reached by technology of thixocasting. The mechanical properties by using semisolid squeeze casting has been increased except the heat treated material.