Efforts are underway in South Africa to ensure that the Oriental fruit fly does not establish itself in the Western Cape following three incursions since late-January. 

One male specimen was detected on Jan. 31 in the Grabouw area in a protein trap and one week later a female specimen was found in the same trap, the Department of Agriculture, Forestry and Fisheries (DAFF) said.

A 5km quarantine area from the detection point was established after the first detection, with fruit growers and packers within a 25km radium placed under quarantine. 

On Feb. 14 a third specimen was detected in a methyl eugenol baited trap approximately 6km from the first detection point close to Grabouw, a major pome fruit-growing area.

The commercial fruit at threat include mango, guava, citrus, papaya, pome fruit, stone fruit, cherry, grapes, passion fruit, bell pepper and tomato.

Hortgro Science's general manager Hugh Campbell said the association had been proactively preparing for the possible occurrence of the pest in the Western Cape for the last decade.

Campbell said there were 1400 monitoring traps in the Elgin, Grabouw, Vyeboom and Villiersdorp region alone that form part of an area-wide monitoring and control initiative for fruit fly. This program is managed by FruitFly Africa (FFA) and supported by DAFF as part of a national surveillance programme.

“Immediately after the first OFF was caught the national action plan was implemented,” Campbell said.

“All growers and packhouses in the region were notified and an area of a 5km radius of the trap was placed under quarantine.”

A removal permit which is based on control and containment actions is now required to move the host material to a pest-free area. A delimiting survey was implemented by FFA to identify the pest's potential spread and growers have implemented weekly control measures.

If no further Oriental fruit flies are caught in any of the delimiting traps for a period of 12 weeks or three generations, the area will be considered as eradicated and the quarantine measures will be lifted. 

According to Campbell, the Asia-origin fruit fly was first discovered in Kenya in 2003 and has established itself in Limpopo, Mpumalanga, North West and parts of Kwa-Zulu Natal.

“It is an evasive fruit fly that can cause considerable damage if not controlled. Its preferred host is mangoes, but it has a wide host range and all efforts are being made to keep it from establishing itself," he said.

This is the first time that it has to be eradicated in the Western Cape and all efforts are being made to ensure that it does not establish itself there or any other regions that are currently free of the pest, Hortgro said.

Campbell said the experience they have from the regions where it has established itself is that it can be successfully controlled in commercial orchards - at a cost - but it has caused considerable damage to mangoes in the informal sector and house gardens where no control measures are implemented.

He stressed that the specific area is under official control and the action plan that is being implemented under the control of DAFF subscribes to the principles of the International Plant Protection Convention. The objective is to isolate the problem area and eradicate the source of contamination.

The remainder of the Western Cape is not affected by this point interception and trade will continue as normal. Fruit trading may, therefore, continue in compliance with established additional risk mitigation procedures.

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