Lowveld
Invasive fruit fly’s wings are clipped
11:37 (GMT+2), Thu , 07 April 2016
Lowveld

Sometimes it can be better the devil you know than the one you don’t know, especially when it comes to the bane of a fruit grower’s existence, fruit flies. 
They are among the most destructive agricultural pests in the world and an invasive, aggressive alien fruit fly even more so, especially when it becomes dominant.
Such an example, the Oriental fruit fly, is steadily trying to take over the role of local fruit flies in Mpumalanga, but its wings might be clipped thanks to an initiative by the Department of Agriculture, Rural Development, Land and Environmental Affairs (Dardlea) and Agricultural Research Council-Institute for Tropical and Subtropical Crops (ARC-ITSC). 
These two organisations are working together to combat the fruit-fly problem, according to Dr. Tertia Grové, senior agricultural researcher at ARC-ITSC. 
The aims of the project is to create awareness of the fruit-fly problem - especially of the Oriental fruit fly species - 
as well as to use research to develop strategies for an integrated fruit-fly control programme. 
In order to alleviate the situation an environmentally sound management strategy need to be formulated with special emphasis for resource poor farmers.
The fruit fly pest from Asian origin was detected in 2010 for the first time in the northern part of Limpopo and for the first time in Mpumalanga in 2012. 
The fruit fly was declared present in the Ehlanzeni District Municipality of Mpumalanga during 2015. 
Agri advisers of Dardlea in Bushbuckridge and Nkomazi municipalities are the drivers of the project. These teams were trained in order to give guidance to farmers on how to manage problems.
The ARC-ITSC placed traps out in the two areas to monitor fruit flies in order to determine the diversity, abundance and seasons that the flies are prevalent. 
Traps were placed out in different habitats such as cultivated areas, rural areas and residential areas.
Dr Tertia Grové said she is excited about the projects’s development. “The project is going well. Communities are taking hands with us to create awareness.” 
The project guidelines were also devised to include detection of the Oriental fly. “Our concern is that in many of the other countries this fly negatively impacted on flies endemic to the region and very quickly dominated the area. We need more information about how it has adapted to our own areas so that we can design a strategy to combat it.”
She foresaw that results might be conclusive enough at the end of the year to formulate a strategy and to put it to work.
The Oriental fruit fly has a wide host- plant range. Mango is one of its preferred crops.
One of the project’s aims is also that a greater awareness be created about fruit flies. They are small to medium-sized 
(2,5 -10mm), often colourful and have patterned wings. The larvae feed on plants. The larvae of certain species develop in the fruit. It is the feeding habits of their larvae that inflict heavy losses.
“Fruit flies are dangerous to the whole fruit industry because export markets can be lost. In many countries, the exportation of fruit is severely restricted by quarantine regulations to prevent the spread of fruit-fly species,” Grové concurred.
An epidemic of fruit flies can have a large socio-economic impact in rural areas where people depend on fruit and vegetables to supplement their income.
“Especially in the Bushbuckridge and Nkomazi areas where households often have fruit trees like mango trees in their backyards as a good source of vitamins, it is important that awareness is spread.”
One way to combat fruit flies is 
orchard or yard sanitation which entails the collection of fallen fruit regularly and burying or by placing it in a plastic bag it in the sun. 
“This is an excellent measure that people in rural areas can use because it doesn’t cost money,” she said.
Another way of addressing a fruit-fly infestation would be to use bait sprays or bait stations. For the Oriental fruit fly the male annihilation technique can be used. This involves the attraction and killing of male fruit flies using a high density of bait stations or substrates. These consist consisting of a male lure combined with an insecticide to reduce the male population to such a low level that mating does not occur. 
The real damage occurs when the female uses her sharp ovipositor to pierce the skin of ripening fruit and then deposits eggs in a small group just below the surface. The maggots that hatch from the eggs feed on the fruit pulp causing soft patches that decay. When fully grown the maggots are about 6mm in length. Fully-grown larvae leave the fruit and drop to the ground. On the ground the larvae develops into a pupa which is enclosed in a puparium. Sometime later the adults emerge. 

 



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