The Incidence and Economic Importance of the Entomofauna on the Growth and Production of Watermelon in Yagoua (Cameroon)

In the Far-North region of Cameroon, watermelon cultivation still faces several constraints that represent a major threat to fruit production. This requires research for maintaining and improving the crop yields. The present study was aimed at investigating the insect fauna associated with watermelon for its optimal management. Observations allowed the identification of insect-visiting fauna to the crop, to assess the role played by each species on growing watermelon, to evaluate the means of protection used by farmers and to make useful projections towards the biological control of the natural enemies of insect pests. Twenty two insect species visited the vegetative organs of watermelon. Fruit flies were found to be the most common and most damaging group for watermelon production. The larval stage of Syrphidae and adults of Coccinellidae and Formicidae were identified as important biocontrol agents. Watermelon requires effective phytosanitary cover for its optimal production. A non-significant fruit set rate was obtained between experimental treatments (T). The rate of mature fruit was zero in T0 which does not benefit from pollination and health care. Protective means used locally guaranteed the production of mature fruits by 24% in T1 without any sanitary care, 36% in T2 impregnated with neem Azadirachta indica (Meliaceae) leaf's extract, and 54% in T3 treated with an insecticide named Optimal. Due to the strong involvement of chemicals in the protection of watermelon production at the study site, their use is often a problem for safeguarding the balance of the ecosystem and the health of farmers and consumers. It is therefore essential to promote the use of pollinators and to protect the natural enemies of insect pests to enhance sustainable production of watermelon in Yagoua.