First ABW damage detected in 2025 season at North Suburb Chicago golf courses

In late June and early July, notable annual bluegrass weevil (ABW) larval damage was detected at both Ravinia Green Country Club (RGCC) and Glen Flora Country Club (GFCC) in the Chicago area, though not on the greens under investigation. At RGCC, damage was found on the fairway of hole no. 7, where a large, irregularly shaped yellow-orange patch appeared in the Poa annua turf on June 27 (Figure 1). Sampling revealed heavy larval pressure, with 15 larvae found in a single 2-inch plug, and lab analysis estimated approximately 130 larvae per ft². Most were 5th instar larvae, though other instars and younger, brown-colored adults were also present. At GFCC, damage was observed in the collar region of Green 17, with significantly less severity. On July 4, soap flushing yielded 32 adult weevils in a 9 ft² area, including several reddish-brown individuals, indicating that these were newly emerged adults. At both locations, the peak emergence of the next generation of ABW adults is anticipated within the next 1 – 2 weeks. Significant larval turf damage at RGCC coincided with the growing degree day (GDD) of 753 on June 27, and at GFCC with the GDD of 843 on June 30.

Adult counts on the investigated green declined significantly after mid-June, with the exception of a spike of 16 adults per 9 ft² at RGCC on June 30 (Figure 2). On the same day, 4th and 5th instar larvae were detected in the collar region of Green 17 at RGCC, while no larvae were found in either the fairway or collar samples at GFCC. As of July 6, the accumulated growing degree days (GDD) are 1004 at RGCC and 997 at GFCC.

The onset of significant turf damage coincided with the early to full bloom of smooth hydrangea (Hydrangea arborescens ‘Annabelle’) (Figure 3).

First ABW damage detected in 2025 season at North Suburb Chicago golf courses

In late June and early July, notable annual bluegrass weevil (ABW) larval damage was detected at both Ravinia Green Country Club (RGCC) and Glen Flora Country Club (GFCC) in the Chicago area, though not on the greens under investigation. At RGCC, damage was found on the fairway of hole no. 7, where a large, irregularly shaped yellow-orange patch appeared in the Poa annua turf on June 27 (Figure 1). Sampling revealed heavy larval pressure, with 15 larvae found in a single 2-inch plug, and lab analysis estimated approximately 130 larvae per ft². Most were 5th instar larvae, though other instars and younger, brown-colored adults were also present. At GFCC, damage was observed in the collar region of Green 17, with significantly less severity. On July 4, soap flushing yielded 32 adult weevils in a 9 ft² area, including several reddish-brown individuals, indicating that these were newly emerged adults. At both locations, the peak emergence of the next generation of ABW adults is anticipated within the next 1 – 2 weeks. Significant larval turf damage at RGCC coincided with the growing degree day (GDD) of 753 on June 27, and at GFCC with the GDD of 843 on June 30.

Adult counts on the investigated green declined significantly after mid-June, with the exception of a spike of 16 adults per 9 ft² at RGCC on June 30 (Figure 2). On the same day, 4th and 5th instar larvae were detected in the collar region of Green 17 at RGCC, while no larvae were found in either the fairway or collar samples at GFCC. As of July 6, the accumulated growing degree days (GDD) are 1004 at RGCC and 997 at GFCC.

The onset of significant turf damage coincided with the early to full bloom of smooth hydrangea (Hydrangea arborescens ‘Annabelle’) (Figure 3).