Palm wine as a food-based bait for monitoring adult Ceratitis ditissima (Munro) (Diptera: Tephritidae) in citrus orchards

Tephritid fruit flies, including Ceratitis ditissima, often invade citrus orchards. These flies cause economic losses to farmers and can prevent farmers from exporting their fruits to foreign markets. To detect the presence of fruit flies in citrus orchards, traps are baited with synthetic lures, which are often expensive for smallholder farmers. Farmers in developing or financially less-endowed countries have to import such synthetic baits, raising the cost of pest monitoring and control. Therefore, we evaluated the potential of palm wine and three other food-based mixtures for trapping C. ditissima and the proportion of non-target flies they trap. Transparent deli cup traps were baited with four different food-based baits, namely palm wine, sugarcane spirit-wine mixture, apple cider vinegar and yeast-sugar mixture. The traps were placed within a citrus orchard on fruit-bearing trees. The content of each trap was collected after one week and evaluated. This was repeated for eight consecutive weeks. Traps baited with palm wine captured more C. ditissima than those with the other baits. Furthermore, the proportion of non-target insects, Bactrocera dorsalis and Drosophila spp., in palm wine-baited traps was less than the other baited traps. This study indicates that palm wine, a cheap beverage across Africa, Asia and South America, could be used to monitor the presence of C. ditissima in citrus orchards. Smallholder farmers who cannot afford expensive synthetic baits could make use of palm wine to monitor fruit flies in their farms.