Rice yellow mottle virus (RYMV), endemic to Africa, is spread within and between rice fields by several species of Chrysomelid beetles and grasshoppers. In Tanzania and particularly in Morogoro, the virus is increasingly becoming a serious problem to rice production. The part of the field and developmental stage of rice at which RYMV vectors are predominantly abundant were not known since the need for the study. The assessment of population abundance of RYMV insect vectors were conducted in the

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... three divisions of Mngeta, Ifakara and Mang'ula of Kilombero district, in Morogoro Tanzania using sweep net in 4 m 2 quadrats. Results revealed the highest abundance of two RYMV vectors, Oxya hyla Serville, 1831 and Chaetocnema sp, on the border parts of the rice fields rather than in the middle parts. The study established that the density of RYMV vectors was dependent on crop growth stages where the number of vectors increased with increase in crop age and it is concluded that the two insects are the main vectors of RYMV in the study area.