GIS Pest Mapping example: Using Maps to Improve Green June Beetle (GJB) Control on Golf Course Turf.
GJB are serious turf pest that trigger blanket broadcast pesticide treatments on golf course fairways. The larvae feed on dead, decaying organic matter (thatch) and to some extent on grass roots. Smaller larvae tunnel horizontally in the top 4” of the soil, loosening the soil, eating roots, and thinning the thatch. Larger larvae dig vertical tunnels, dislodge turf roots, and push loose mounds of acidic subsoil to the surface. Disturbed areas of grass often wilt and die, and weeds often invade mounded areas. The mounds compromise the playing surface, quality of the golf course turf, and damage mowing equipment. Predators such as small mammals and birds often damage GJB infested turf as they dig for the larvae.
However, as the map below shows; GJB are like most other pest, they occur in clumped distributions.
To sample for GJB we employed a simple hoop that was tossed to the ground and the number of mounds counted or an infestation rating assigned.
DATA CONTOURS AND TREATMENT MAP
As a demonstration project we focused on fairway 18. Our goal was to provide a treatment map to the spray technician which he could simply follow visually. Golf course fairways are unique in that they have numerous landmarks such as yardage markers, hazards and permanent irrigation sprinklers whose distance to the green is marked. We georeferenced these landmarks and our sampling sites and prepared a map.
The figure on the left shows an outline of the fairway and raw data contours where 6 mounds per hoop were found. The superintendent selected 6 mounds per sampling ring as his threshold for pesticide treatment. However, the map on the left would be difficult to follow while spraying.
The figure on the right shows the map we handed the pesticide applicator. We drew boxes around the infested areas and included landmarks on the map such as sprinklers and yard markers. Since this was done in a GIS platform the program also returned to us the amount of area that needed to be treated so the exact amount of insecticide could be mixed.
PRETREATMENT AND POSTREATMENT MAPS
During the pesticide treatment we marked and georeferenced the area of actual pesticide application. The actual treatment areas, shown on the map on the left, proved to be fairly close to those proposed on the map we provided the applicator and more importantly, they did effectively cover the infested areas.
The background picture shows the dead larvae which frequently die on the surface of the turf. The map on the right is the GJB population 30 days after treatment. With this targeted pesticide application we were able to get 90% control by treating less than 30% of the area than would normally be treated.