Studies on the Distribution and Integrated Management of Fruit Flies in Sudan

Abstract

This Study was carried out at three States which are Khartoum,Sennar, and Kasala States during the period 2010 to 2018. During the period 2010 – 2011 field and laboratory studies were undertaken through surveying and monitoring of fruit flies species, and the results revealed that, four species were found in association with mango and guava in the study sites. These species were, Bacterocera invadens, Ceratitis cosyra, C. quinaria and C. capitata. Among them, B. invadens was the most dominant in all study sites. Moreover, the sex ratios of the different fruit flies species were determined and showed that, females of B. invadens outnumber the males by three to four folds, while females of other Ceratitis species were two to five folds of the males. During 2012 to 2014 studies were carried out in laboratory and field to evaluate the effectiveness of naturally extracted B. invadens host marking pheromone (HMP). Treating of mango and guava fruits with different concentrations of B. invadens faeces pheromonal extracts (2.5, 5, 10 and 15%) significantly reduced fruit infestation (number of larvae per fruit (P< 0.0001). The effectiveness of the faeces pheromonal extract was surprisingly uniform. As the results were promising, more studies were carried out for Structural Elucidation of the natural HMP using HPLC and GC-MS. The results of the experiments showed that, the natural pheromone extract according to the development of chromatographs of HPLC in the first analysis contain 17 peaks, 32 peaks for the second analysis and the samples analysis by GS-MS showed the presence of 42 compounds. The last part of the study was carried out during 2015-2018, as we encountered problems in fruit flies control measures in study sites that lead to increase in fruit fly infestation and reduction in fruit production. Further experiments were carried out to investigate the problem. It was found that fruit flies numbers trapped by locally manufactured Lynfield traps baited with Methyl Eugenol, mixed with malathion (57%) ranged from 4 to 440 flies per trap per week. The present results compared to former studies in same study sites showed a decrease in hatchability. To investigate the reasons of the decrease in traps catchability, we evaluate different types traps. The results showed that, the Sticky Traps catched the highest mean number of trapped fruit flies, followed by Lynfield trap baited with Methyl Eugenol mixed with malathion (57%) and Guava fruit juice. During checking of the traps and counting the numbers of flies, a new species of fruit flies was noticed, which was identified later as, Bactrocera zonata. B. zonata was reported to be resistant to malation and this could be the reason catchability of traps decreased in comparison with previous studies. A newly designed two liter plastic bottle trap was compared with the locally manufactured Lynfield trap which is used for mass trapping in the study area (1st Trap)”.The result showed that the range of catched flies per trap per week between (28 to 75) for the 1st trap and (863 to 1659) for the 2nd trap , The structure of the new designed two liter plastic bottle trap, with one upside down hole make it difficult for the flies to get out of the trap and hence be exposed to the pesticide for long time