Developing a systems approach for Sternochetus mangiferae (Coleoptera: Curculionidae) in South Africa

Sternochetus mangiferae (F.) (Coleoptera: Curculionidae) is a quarantine pest of mango, Mangifera indica L., in South Africa. The aim of the study was to test cultural and chemical control measures in a systems approach for risk mitigation of S. mangiferae in South Africa. A large-scale experiment, using a randomized block design with three replicates, was undertaken on 'Tommy Atkins' mangoes in South Africa. Five treatment combinations were applied over two seasons: (1) untreated control; (2) sanitation and physical removal of egg-infested fruit (P+S); (3) thiamethoxam, P+S; (4) thiamethoxam, fipronil, P+S; and 5) thiamethoxam, two fenthion applications, P+S. A weekly random sample of eight fruit from 40 trees per orchard was taken from 5 wk to harvest over two harvest periods. In total, 57,600 fruit were sampled. In a separate experiment, the same variety was used to test the efficacy of covering fruit with paper bags over one season in a completely randomized design. In both trials, all the pests were recorded from internal and external fruit inspections. In trial 1, results after the first season showed >98% control in the three chemical combination treatments. In the second season, treatment 2 provided 19% and treatment 3 99.9% control, whereas no fruit were infested with S. mangiferae in treatments 4 and 5. Trial two showed that fruit bagging significantly reduced S. mangiferae infestation. The data showed that a systems approach for S. mangiferae control in South Africa can be effective and that bagging can be an effective organic control option.