Fruit Flies in Oman: Characterization, Seasonal Population Dynamics, Height and Direction of Flight Activity, and Efficacy of Physical Barriers for their Management

Fruit flies are major pests of fruits of fruit trees and vegetables in Oman. The significant damage they cause on fruits has become a major concern to farmers, especially farmers of the AlBatinah Farmers Association. Due to the lack of stringent application of quarantine laws, a number of fruit fly species were possibly introduced and became invasive in the last few decades (e.g. peach-guava fruit fly). Due to their aggressive nature, lack of effective natural enemies, and socio-economic changes related to agriculture in the last 60 years (especially after 1970), populations of these fruit flies increased rapidly causing destruction of fruits and diminishing yields from fruit and vegetable farms. The impact of fruit flies on farmers is of great concern due to the ability of these pests to damage fruits on many different crops, whether fruit trees or herbaceous vegetables (such as cucurbits). It can be estimated that at least 30-40% of the fruit produced in Oman is destroyed by fruit flies. Two species of fruit flies are confirmed to be regular and severe pests of fruits in Oman. Bactrocera zonata damages fruits of different fruit trees such as citrus, mango, guava, and ber (sidr), while Dacus ciliatus damages various cucurbits. Other less important fruit flies include two species of Carpomya on fruits of Ziziphus, and four species on wild plants. There are unconfirmed reports of other fruit fly species in Oman including B. dorsalis (on fruit trees) and Zeugodacus cucurbitae (on cucurbits). There is lack of data on the current status of fruit fly species in Oman (last extensive survey was done by CAMS team in 2003-2005). Moreover, there is no effective strategy for dealing with these severe and perennial pests of fruits. Therefore, this project aims to update our knowledge of the fauna of fruit-feeding fruit fly species found in Oman, both on cultivated and wild plants and characterize these species both morphologically and molecularly. A second objective involves determining the spatial and seasonal flight activity of fruit flies using different types of traps in some representative farm(s) of Oman. Spatial activity will focus on flight height level and direction of fruit flies as they disperse into farm(s). A third objective involves testing of physical barriers at farm borders, row covers for cucurbits, and kaolin for fruit trees. It is expected that the project will provide a database on fruit flies of Oman in terms of species available, their morphological and molecular characteristics, distribution, host plants, and natural enemies. Information from flight height, direction, and seasonal flight activity will help in application of physical barriers that will reduce fruit fly populations reaching cucurbit vegetables and fruit trees, thereby minimizing damage to these fruits. This will provide novel tactics for sustainable management of fruit flies without resorting to insecticides.