Review of pests and diseases of sesame in Uganda

Abstract

Sesame is attacked by numerous pests and diseases that reduce its yield and lower the quality of the seed. Thirty eight insect pest species have been found to infest sesame in Uganda, of which the sesame webworm (Antigastra catalaunalis Dup.) and the gall midge (Asphondylia sesami Felt.) are considered most important, with 62% and 98.8% occurrences, respectively, in northern Uganda. A. catalaunalis was found to have the highest relative incidence of 0.63. Mean percentage capsule damage due to Asphondylia sesami ranged between 29 to 34.3% among the various sesame varieties. Various control measures have been recommended against these two pests although not many of them are being applied in Uganda. On the other hand, diseases are generally considered to cause less damage to sesame than pests. However, sesame is affected by a number of fungal, bacterial and viral diseases worldwide whose effects on yield loss in Uganda have not been assessed. Elsewhere, yield loss of 45% have been attributed to the powdery mildew, Luveilluta taurica Lev. and 54.5% to the phyllody disease. In Uganda, leafspots, wilt, leaf curl virus and powdery mildew have been recorded, although no assessment of their economic importance has been done. An on-going assessment of incidence and severity of these diseases by Makerere University has indicated that the incidence and severity of some of these diseases are significantly affected by time of planting. Leafspot severity and incidence were highest for crops planted at the onset of rain and the reverse was true for wilt disease. Incidence of leaf curl diseases on the other hand was highest for crops planted two weeks after onset of rain.