A suspected male Queensland fruit fly was found in a trap in the Seville area.
The fly was sent to Crop Health Services for further verification following the discovery on Friday 3 May.
Within 1.5 kilometres of the detection are regions of Seville, Seville East, Wandin East and Yellingbo.
Bronwyn Koll, Agribusiness Yarra Valley QFF regional co-ordinator, said all fruit producers in the area should stay vigilant and fruit and farm hygiene, fruit fly monitoring, and consider the value of fruit fly baiting going into the tail end of the season.
Any fruit fly pressure that is removed now reduces the chances of QFF overwintering as adults, potentially able to cause damage next season.
The region’s warm April probably supported this QFF activity.
Ms Koll said farmers should also check non-commercial host plants in perimeter areas, around dams and sheds, and look in the house yard.
Citrus, pome, autumn berries and late plums might all be hosts still, as is the native kangaroo apple.
An extra 22 traps have been placed on five properties to help determine if this is a one-off or if there is an established population in the area.
All neighbouring properties have been notified personally.
Inform Ms Koll of any QFF detections in on-farm investigations on 0490 381 999 or firstname.lastname@example.org.
Supplementary trapping is available to assist in early response.