Development of a local baiting system for the control of the Africa invader fly, (Bactrocera invadens) Drew, Tsuruta and White (Diptera: Tephritidae) in mango orchards at Somanya, Eastern Ghana

Fruit production plays an important role in Africa's economy. In Ghana, mango is targeted as one of the next non-traditional export crop that is expected to fetch the highest foreign exchange for the country and replace cocoa. Ghana's current production is said to have increased from 6,800 tonnes in 2007 to about 7000 tonnes in 2010. However, the African invader fruit fly, Bactrocera invadens, is causing high yield losses as an important quarantine pest and has brought some setback in the mango trade between Ghana and their exporting destinations. Imported commercial protein hydrolysate bait for controlling the flies constitutes the highest cost component of the control programme, excluding cost of labour. The baits are exhorbitant for local farmers and seldom available. This setback has called for the need to design and implement efficient and cost-effective control regimes for managing this pest. The objective of the study was to explore the development of locally produced, cheap and efficient baiting system using brewery yeast wastes and coloured cylinder traps to attract and control this quarantine pest. A 1 ha study area was selected within DORMEHSCO FARM, a mango orchard at Somanya in the Eastern region of Ghana with the Keith mango variety for the study. Local sources of Guiness, Beer and Pito yeast wastes were collected into Winchester bottles and subjected to pasteurisation. Papain enzyme was added to maximize yeast cell autolysis at 70 degrees celcius for 9 hours. The Micro-Kjeldahl apparatus was used to determine the percentage protein in each waste. Transparent cylinder traps with three different colours of lids (red, yellow and green) and three 3cm diameter round holes referred to as coloured traps were used to dispense the baits. The traps were labelled according to the type of bait and trap colour combination. The trials were conducted in two successive peak fruiting seasons fron October to November, 2011 (minor season and then from April to June, 2012. The selected area was divided into three to constitute a randomised complete block design. The traps were replicated three times. The coloured traps were randomly suspended on selected trees in two rows, 15m from each other within each block and about 2m from the ground. The cotton wads hanging inside the traps were soaked with the baits incorporated with fenitrothion insecticide. Fly catches were collected weekly, recorded and the traps recharged. Counts of fly catches were log-transformed, subjected to analysis of variance and least significance difference determined. Results of the study showed that the percentage of supernatant increased slightly after pasteurisation, with a corresponding decrease in the sediment mixture. However, the quantity of yeast cell sediments used for pasteurisation did not affect the protein content of the bait. Protein content of Guiness, Beer, Pito and Commercial baits were 1.4%, 5.2%, 1.4%, and 8.0% respectively. Beer bait was found to be significantly attractive with peak fly catch of 7.19 flies per trap per week (F/T/W). Guiness and Commercial bait were not significantly different in their fly catches with peak catches of 6.54 F/T/W and 6.61 F/T/W respectively. In season I, green coloured traps recorded the highest fly density of 5.56 flies per trap per day (F/T/D), while yellow coloured traps captured the highest with 17.11 F/T/D in season II. The relative fly density in the study area was estimated to be 4.68 F/T/D in the minor season and 14.64 F/T/D in the major season. An overall sex ratio of female B. Invadens was 77%. Beer bait proves to be more efficient and effective in controlling B. Invadens. Large scale production of protein bait for effective monitoring and control programmes should therefore combine Beer protein autolysate and green or yellow coloured traps in a baiting system. [au]