Studies were carried out in Nigeria on oviposition and the deadhearts caused by Diopsis macrophthalma Dalm. on ten rice varieties. The varieties were divided into three groups according to the numbers of eggs recorded on them. Strong positive correlations existed between (a) the numbers of eggs and tillers, (b) the numbers of eggs and deadhearts, and (c) the numbers of deadhearts and tillers. Some varieties compensated for damage by the production of new tillers. In the variety Suakoko 8, most of the eggs were confined to the leaf blades in young plants and to the leaf sheaths as the plants grew older. Peak oviposition occurred 30–40 days after transplanting. Some implications of the results for a pest management programme are discussed.