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Home > Plants, Pests & Pest Control > Pest Management > Gypsy Moth Program > Trapping Survey

Gypsy Moth Trapping Survey

Each year the MDA sets around 20,000 gypsy moth traps throughout Minnesota to find out where gypsy moth populations exist. The MDA's trapping survey program is closely tied to the insect's biology. The female does not fly so she uses a pheromone, or sex attractant, to lure the male moth to her for mating. Although humans can't detect the scent of the pheromone, it is a powerful attractant to the male gypsy moth.

Five gypsy moths caught in a trapThe survey detects the presence of the moth. The traps are set before the adult moths fly, are monitored throughout the summer, and are removed after the flight season is finished. Data are collected about the location of the trap and the number of moths caught in it, if any. The data are then used to determine if gypsy moth infestations exist and to give an idea of how widely the population is dispersed.

MDA survey staff and cooperators deploy weatherproof cardboard traps. Triangular delta traps can be orange or tan in color and are the standard trap type used. Milk carton traps are green and are used in areas where the expected moth counts are higher than what the delta traps can accommodate (>15 moths). Both trap types have a lure inside that mimics the natural pheromone of the female moth. The male moth flies to the trap to mate but instead ends up ensnared in a sticky substance inside the delta trap or perishes from the pesticide strip in the milk carton trap.

A delta orange gypsy moth trap
Delta Trap
A green milk carton trap
Milk Carton Trap


30–45 survey staff are employed each summer to set, check and remove the traps. It is a full-time seasonal position that requires considerable driving and the ability to work outdoors in all kinds of weather.

Job Opportunities

Check out opportunities to be a gypsy moth survey trapper.

Trapping Survey in Minnesota

The gypsy moth trapping survey program concentrates on the eastern border of the state because the natural movement of the main population is moving westward from Wisconsin. Selected high-risk businesses also receive survey traps throughout the annually designated trapping survey project area. 

Over the years, the trapping survey has shown us where gypsy moth populations are starting up, building, and moving: 

Please view the 2015 gypsy moth trapping survey results map. 

MDA 2015 gypsy moth trapping survey results map.

Gypsy moth trapping results: 14,170 traps set, 522 moths caught. 2013 Gypsy Moth Trapping Results: 13,891 Traps, 70,935 Moths caught

2012 Gypsy Moth Trapping Results2011 Gypsy Moth Trapping Results

Gypsy Moth 2010 Trapping resultsMinnesota map showing 2009 gypsy moth trapping results

2008 Gypsy Moth Trapping Results2007 Gypsy Moth Trapping Results

2006 Gypsy Moth Trapping Results2005 Gypsy Moth Trapping Results

2004 Gypsy Moth Trapping Results2003 Gypsy Moth Trapping Results

2002 Gypsy Moth Trapping Results

MDA Contact

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