Dispersal of the alate forrns of Cerataphis variabilis H.R.L. (Homoptera: Pemphigidae) in a raphia plantation.

ENOBAKHARE, D.A. and E.O. OSISANYA

ABSTRACT: The abundance and dispersal of alate Cerataphis variabilis was’ studied at the Nigerian
Institute for Oil Palm Research using sixteen sticky traps each measuring 0.9mx0.9m in Raphia plantation. Each trap, a flat vertical square wooden board, was covered with sulphite-yellow cardboard paper measuring 0.521mx0.635m. These traps were smeared
with semi-solid transparent grease and were laid out at specific locations in a Raphia field. Counts of trapped aphids were made daily. There was a positive correlation between the number of adult alatea and the total aphid population (r=0.68..,. p<-O.001). The numbers of ‘singed aphids trapped outside the experimental field were-closely related to those trapped
at the edge of the field (r = 0.92, P<0.001) and at 19.6m from the periphery (r = 0.93, P 0.001). On a fine day, large numbers of alatae took off from the Raphia palms. The relative abundance and aerial movement of alate C. variabilis in the Raphia field are discussed.

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