Plant Industry - Blueberry Certification Program

Blueberry Certification Program

The blueberry maggot (Rhagoletis mendax; BBM) is an important pest of commercially-grown blueberries.  The pest was first detected in Maine and New Hampshire in 1914 and has since spread throughout the eastern United States and into some provinces of Canada.  The Canadian Food Inspection Agency (CFIA) has developed requirements to prevent the spread of this pest to non-infested areas of Canada and blueberry growers in North Carolina who ship fruit to Canada are required to participate in the Blueberry Certification Program to ensure their blueberries are blueberry maggot-free.

What is blueberry maggot and why should you be concerned?

Berries infested with the blueberry maggot become extremely soft and watery making them unmarketable for both fresh markets and processing.  During the early stages of the maggot’s development, it is nearly impossible to detect whether or not the berries are infested.  As development progresses, you may see an abundance of fruit dropped on the ground.  Other signs to look for are tiny puncture holes on the skin of the fruit and collapsed berries.  The CFIA has established protocols in order to detect whether or not your fruit is infested with this pest.  In the past, this was done via cooking the berries, but as of June 1, 2015, growers must now perform either a sugar or salt flotation test (steps outlined in a document here) to monitor for the blueberry maggot.

BBM has four life stages: egg, larva (“maggot”), pupa, and adult fly.  The two stages we are primarily concerned with are the larval stage (detected via flotation method) and adult fly stage (detected via trapping).  BBM larvae are light-colored, legless, lack a head capsule, grow up to 8 mm in length, and are tapered at one end and blunt at the other (like a carrot).  In addition to BBM, there are several other insect larvae that can infest blueberries and their distinguishing characteristics can be found in the table below (Table 1).

Blueberry Maggot
Adult Blue Berry Maggot Fly
Blueberry maggot in blueberry
Adult blueberry maggot fly
Photos by Rufus Isaacs, Michigan State University

Table 1. Distinguishing between insect larvae found in blueberry fruit (Table courtesy of Ontario Ministry of Agriculture, Food, and Rural Affairs)

Insect Pest

Head (other)

Legs (other)


Size of mature larva

Blueberry maggot

No head capsule (black mouth hooks)

No legs


8 mm, pointed at one end, blunt at the other

Cranberry fruitworm

Brown head capsule

3 pairs of legs (plus abdominal prolegs)

Light green

9-10 mm

Plum curculio

Brown head capsule

No legs


7-9 mm, C-shaped

Spotted wing drosophila

No head capsule (black mouth hooks)

No legs


5-6 mm, tapered at both ends


What are Canada’s requirements and should you participate in the Blueberry Certification Program?

The purpose of the Bluberry Certification Program is the facilitate movement of fresh blueberries from areas regulated for blueberry maggot to non-regulated areas while mitigating the risk of moving blueberry maggot outside the regulated area. Phytosanitary requirements established by the CFIA require that blueberry producers from the United States comply with the protocols established in the CFIA directive D-02-04 to prevent the introduction of blueberry maggots (Rhagoletis mendax) to non-infested areas of Canada. Blueberries infested with the maggot will NOT be allowed into Canada.

The Integrated Pest Management trapping guidelines and BBM detection protocols are outlined in the trapping and detection protocols (see under 'Helpful Links' below) . Each year, NCDA personnel will start the inspection process within one week of the projected blueberry maggot flight (approximately the second-to-last week of May) to help assist blueberry producers in the program.

If you ship any of your blueberry crop to Canada, you are required to participate in the Blueberry Certification Program.  If you are a new blueberry grower and want to join the program please contact Paul Adams (919-707-3742).  The deadline for participation in the program for 2022 is March 4, 2022.


Helpful Links:


If you have additional questions please contact:
Paul Adams, Entomological Programs Manager
Phone: (919) 707-3742
Fax: (919) 733-1041