Management of Pests of Quarantine Importance in Ghana’s Export Vegetables (Chili, Eggplant and Ridged Gourds)

Abstract

The Ghana vegetable exports experienced several interceptions from 2012 to 2015, largely due to the presence of harmful organisms, specifically quarantine pests (thrips, whiteflies, fruit flies and false codling moth) in the consignments destined for export to the European Union. Therefore, Ghana was placed under a ban for some vegetables, such as chili pepper, eggplant, aubergine, and gourds. This situation lasted from 2015 until December 2016, and was further extended to December 2017. Consequently, the Ministry of Food and Agriculture (MoFA) set up an Exports Taskforce to help reverse the ban. In spite of the progress made, well-coordinated scientific research was weak in these efforts. Here we discuss the outcome of the scientific interventions undertaken between 2016 and 2017, to ensure that these pests of quarantine importance were effectively managed at the farm level. These interventions also endeavoured us to equip the Plant Quarantine Inspectors (PQI) of the National Plant Protection Organisation (NPPO), known as Plant Protection and Regulatory Services Directorate (PPRSD) of MoFA, with updated knowledge on the sampling, detection and identification of these pests to ensure pest-free export produce. A quick survey was undertaken to understand the crop protection strategies employed by farmers (farmer practices), and the gaps identified were then taken into consideration in the development of a scientific protocol that was tested in the exporter farms. The protocols comprised the testing of six products belonging to different classes of insecticides (synthetic, botanical, microbial and physically acting), use of sticky traps, food baits and lures for the target pests, and the promotion of good farm hygiene. The action was targeted at three selected crops: chili, ridged gourd and eggplant, in six selected out-grower farms of exporters, in three different agro-ecological zones. From the quick-scan survey, poor farm hygiene (mainly heaps of rotten fruits left lying near the farm) was the main source of re-infestation for false codling moths and fruit flies, onto newly established crop fields. Species-specific lures for mass trapping of false codling moths and fruit flies offered an effective control of these pests, with fruits harvested and incubated being generally pest free. Aqueous neem kernel extract (ANKE), Maltodextrin 282 g/L, Bacillus thuringiensis (32,000 IU/mg), and Acetamiprid 16 g/L + Indoxacarb 30 g/L were among the most effective insecticides for the target pests. The outcome of the trial was used as baseline information, to be used in addition to best crop protection practices, for developing an Integrated Pest Management (IPM) strategy known as a roadmap for pest reduction on the target export vegetables. This roadmap was further implemented through demonstration trials in over ten exporter out-grower farms, to help upscale the technology and disseminate the information to the greater numbers of exporters and their out-growers, field staff of PPRSD, MoFA Agriculture Extension Agents, and other relevant stakeholders. The training of the PQI at the point of exit ensured that produce sent through the exit points are pest free. The positive steps undertaken ultimately influenced the decision of the EU Commission to lift the ban on the export of the selected vegetables, from 1st January 2018.