Several grub species impact the roots or stems of cool season grasses within the Midwest. Turf managers must be aware of the symptoms and damage that each species can cause due to the impact to turf quality on golf courses, home lawns, and sports fields the grubs can have. The most common grub larvae that continue to impact turfgrass roots are both the Japanese Beetle and S. Masked Chaffer.
Both adult beetles are distinguished by their color as well as their flight patterns. SMC typically fly at night, are attracted to light and can be observed on driveways or sidewalks. The Japanese Beetle, on the other hand, flies during the day and can be observed feeding on flowers and leaves. Once mating has occurred, eggs are deposited into the turf. Within one month, grub larvae emerge and begin to chew on grass roots below the soil surface.
Another grub species that is one of the misdiagnosed is the bluegrass billbug. This beetle has an easily identifiable feature, its elongated snout. Females use it to lay an egg in the stem of the plant. The tiny larvae feed inside the stem, which causes the turf to appear wilted. To see if bluegrass billbugs are present, employee the “tug test.” Pull upward on the affected turf stems and see if you see a “legless” grub at the base of the plant. Sometimes weakened or dead plants can be associated with the early stages of damage.
Another grub species that is one of the misdiagnosed is the bluegrass billbug. This beetle has an easily identifiable feature, its elongated snout. Females use it to lay an egg in the stem of the plant. The tiny larvae feed inside the stem, which causes the turf to appear wilted. To see if bluegrass billbugs are present, employee the “tug test.” Pull upward on the affected turf stems and see if you see a “legless” grub at the base of the plant. Sometimes weakened or dead plants can be associated with the early stages of damage.
The black turfgrass ataenius or BTA is the tiny grub that exclusively impacts golf course turf consisting of bentgrass and/or annual bluegrass. These small beetles can overwinter in plant debris or near woods and emerge the following spring where they can produce 1-2 generations of grub larvae. BTA beetles and their damage can occur during the same time as other grub beetle complexes.
Choosing the correct insecticide for controlling various grub complexes begins with proper timing and selection of granular or sprayable applications. Almost every turf manager selects a preventative approach using new class chemistries (CNI – Merit Mallet or Arena or Chlorantraniliprole – Acelerpryn) for only one application per season. Product applied to the turf will control for various larvae instars before damage occurs. Watering in is recommended to move active ingredient into the soil and reduce any photodegradation. Applications can begin during the month of May or early June to optimize control.
Should a curative treatment need to be used in the late summer/fall, Dylox® granular, from Bayer®, is the best choice for controlling both small and large instars. Dylox needs to be irrigated to be effective and only lasts for less than a couple of weeks.
The #1 question about the grub forecast for 2017? Will we have higher populations of grubs this year? Yes, I believe we will have higher populations due to the higher precipitation from last summer.
John Turner
John Turner
Sales Account Manager, Advanced Turf Solutions
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