Figure 1. Overview of the bluegrass billbug adult.
Tere are nine major billbug species that cause damage to turfgrass in the United States with the bluegrass billbug and hunting billbug being the most widely identified as causing visible damage (Vittum et al. 1999). In the transition zone and cool-humid region, adult billbugs can be active across the growing season from March through November. In regions like the Midwest, they become active in April or May as soil temperatures warm and eventually deposit their eggs in stem tissue and the legless larvae begin their feeding (Figure 2).
Multiple generations of billbugs frequently overlap throughout the growing season extending the time period when both adults and larvae may be present. For the bluegrass billbug, turfgrass damage is associated with the larvae, while for hunting billbugs the adults are most damaging. In short, this paints a complicated picture concerning the most effective suppression strategies for billbugs and has strong implications for proper pesticide application timing to achieve maximum effectiveness.
Figure 2. A typical larvae of bluegrass billbug in the soil.
Tese larval survival data are similar to what has been documented for other insect pests like white grubs. Grubs did not survive at 0 percent soil moisture. Survival increased with increasing soil moisture, but at high soil moisture, survival decreased. Te effects of soil moisture on larval survival is important information to aid in advising turf managers of optimal timings for insecticide applications.
Given the long egg-laying period and visible damage associated with adult hunting billbugs, suppression efforts should target when the adults are active. Monitoring strategies like scouting for adult activity immediately after sunset or the use of pitfall traps may also improve pesticide application timing efforts.
While a number of insecticides can be used to suppress billbug populations, there are also effective non-chemical options for chronically affected lawns. In a prior “Rooted in Research” article from January/February 2022, I highlighted research that was conducted in Ohio on a chronically affected Kentucky bluegrass lawn that was overseeded with an endophyte-enhanced perennial ryegrass, to suppress billbug populations (Richmond et al, 2000). Te researchers reported that this was an effective non-chemical strategy to manage and suppress billbugs.
Side note: Dr. Doug Richmond has an excellent fact sheet related to billbug management which can be found at the link that follows.
https://extension.entm.purdue.edu/ publications/E-266/
E-266.html
Since billbugs are complicated, turf managers need practical guidance in the best suppression strategies and Dr. Brandenburg’s entomology research lab conducted a series of hunting billbug studies to better understand their behavior and how environmental factors like soil moisture may affect this insect in North Carolina (Reynolds et al, 2016). Teir specific objectives were to determine the overwintering life stages, larval survival under different moisture regimes, and oviposition (this is simply a fancy word for egg laying) and feeding behavior of adults.
One of the more important findings of this research was that egg-laying data indicated that larvae could be present at any time throughout the year. Since there is such a long period of larval activity, understanding how factors like soil moisture status affect larval survival was important. In this study, they found that hunting billbug larvae mortality was lowest under low moisture status and highest under very wet conditions. Tis is important since higher larval survival results in more emerging adults that could damage turfgrass.
In closing, I wanted to offer a sincere THANK YOU to Dr. Brandenburg for his many contributions to the discipline of turf science and the betterment of humanity in many parts of the world.
References: Reynolds, D.S., W.C. Reynolds and R.L. Brandenburg. 2016. Overwintering, oviposition, and larval survival of hunting billbugs (Coleoptera: Curculionidae) and implications for adult damage in North Carolina turfgrass. J. Economic Entomology. 109: 240-248.
Richmond, D.S., H.D. Niemczyk and D.J. Shetlar. 2000. Overseeding endophytic perennial ryegrass into stands of Kentucky bluegrass to manage bluegrass billbug (Coleoptera: Curculionidae) J. Econ. Entomol. 93:1662- 1668. doi:10.1603/0022-0493-93.6.1662.
Vittum, P. J., M. G. Villani, and H. Tashiro. 1999. Turfgrass insects of the United States and Canada, 2nd ed. Cornell University Press, Ithaca, NY
Cale Bigelow, PhD, is a professor of Turfgrass Science and Ecology in the Department of Horticulture and Landscape Architecture at Purdue University in Indiana. Mike Fidanza, PhD, is a professor of Plant and Soil Science at Pennsylvania State University, Berks Campus. They are teaming to provide a Rooted in Research article for each issue of Turf News. Photos courtesy of Dr. Doug S. Richmond.
TPI Turf News January/February 2025 55
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58 |
Page 59 |
Page 60 |
Page 61 |
Page 62 |
Page 63 |
Page 64 |
Page 65 |
Page 66 |
Page 67 |
Page 68 |
Page 69 |
Page 70 |
Page 71 |
Page 72 |
Page 73 |
Page 74 |
Page 75 |
Page 76 |
Page 77 |
Page 78 |
Page 79 |
Page 80 |
Page 81 |
Page 82 |
Page 83 |
Page 84
