About

The major dipterans attacking rice in West Africa are the African rice gall midge, Orseolia oryzivora and the stalk-eyed flies Diopsis spp. The adult gall midge is mosquito-like in appearance and does not cause plant damage. The gall midge is primarily a pest of irrigated rice. The larva produces a distinctly characteristic plant damage symptom- a gall resembling an onion leaf, called a ‘silver shoot’, in place of a panicle. The Diopsis adults are easily identified by the characteristic eyes which are borne on stalks. The stalk-eyed borer is not known to attack crop plants other than cultivated rice. Only the diopsid larvae damage the rice plant by boring (stem borer) in the stem which results in a dead heart (dead central shoot). Damage differs from that of the pyralid stem borers as the damage only causes dead hearts, not whiteheads. Diopsid damage delays booting and leads to a decline in the number of panicles. If diopsid damage occurs early, it may cause total crop loss’; if it occurs later in the rice development stage, some varieties compensate for damage by producing new tillers.