A Survey of Rootstock Usage and their Influence on Major Insects and Diseases of Citrus in Nigeria

Abstract

In the various agro-ecological zones of Nigeria, most farmers do not use the recommended rootstocks that enable the production of vigorous and pest/disease resistant plants. Consequently there are many reports of citrus stand losses and low fruit yields in pest and disease endemic areas. This necessitated the initiation of the present study with a view to appraise the validity of existing rootstocks and evaluate, where necessary, new ones adapted to the areas lacking appropriate ones. Questionnaires were administered to 84 citrus farmers in selected producing areas of Nigeria and field visits were made to sample for pests and disease incidence in their farms. The questionnaires covered citrus types and varieties cultivated, sources of planting materials and rootstocks used, pests and diseases causing damage. Results indicated that the citrus types cultivated were in the following decreasing order of preference: sweet oranges (100 % of the farms), mandarins (32 %), tangelo (30 %), grape (28 %), lemon, lime and shaddock altogether were cultivated in 20 % of the farms. Seedlings were either obtained locally or from agricultural agents. Some
farmers combine budded seedlings with seedlings from seeds to establish their orchards. Often, the rootstocks chosen for seedling production were not based on recommendations. Only 16 % of the farmers used the recommended rootstocks. Major insect pest and disease attacks that directly correlated with stand losses included those of termites, scale insects, aphids, Phytophthora and tristeza. The rootstocks used affected the severity of some pests and diseases when compared.