Homopteran pests complex of citrus (Citrus Sinensis) in semi-arid Kenya

Abstract

On farm studies in collaboration with farmers who grow citrus were conducted in upper midlands and lower midlands agroecological zones in Machakos district Kenya. The aim of the study was to understand the factors affecting population fluctuations of homopteran pests attacking citrus in Kenya. White flies (Aleurothrixus flocossus Maskell) and black flies (Aleurocanthus woglumi Ashby) were the most common pests of citrus observed throughout the monitoring. Aphids (Toxoptera citricidus Kirk.) and psyllids (Triozae erytreae Del Guercio) were occasional pests while scales (various) were rare attacking only a few plants within the farms. Time period of sampling had an effect on whitefly, psyllid and blackfly populations. Aphid populations were not affected by the sampling time period. However, there were ecological differences in the development of aphid, blackfly and psyllid populations. It has been observed that populations of homopteran pests on citrus trees do vary with time. There was one major flush period of the citrus trees during the monitoring period. High aphid and psyllid populations seemed to coincide with the flush period. Flushing of the trees may have contributed in the variation of the pest populations that were being monitored. These findings are discussed in relation to their possible use in the development of integrated pest management (IPM) strategies for the management of these pests.