Insect pest situation and farmers' cultural practices in citrus orchards in the Southern Guinea savannah agro-ecological zone of Nigeria

Abstract

A survey was conducted in the major citrus producing areas located in Southern Guinea savannah agroecological zone of Nigeria to identify major insect pest and assess the effects of farmers' citricultural practices on citrus production and pest control. Various species of insect pests were identified attacking citrus. The major leaf feeders were the scale insects which infested a mean of 13 % of the trees, the leaf miners (8.7 %), aphids (10.6 %) and the swallowtail butterfly larvae (23.7 %). Termites damaged the exposed parts of roots and the woody structure of some citrus trees, and was suspected to have positively influenced the spread of Phytophthora-induced diseases (r = 0.75; P<0.01; n = 10). Fruit drop caused by fruit piercing insects occurred in 30 to 90 % of sampled trees per farm. Major citrus diseases observed included the citrus tristeza disease, foot rot, brown rot and leaf spot diseases. Farmers' pest/disease management practices were ineffective. Factors that contributed to unsatisfactory control were highlighted.
Keywords: Citrus, fruit drop, insect pests, die-back, pest-disease complex, intercropping