Active Turf Insects
Posted: April 18, 2012
We get many questions about how to predict pest activities based on weird weather conditions. Predictions are always scary, but two things are certain.
- The insects are developing in line with the weather conditions, and it may mean you’ll need to adjust the timing of scouting and management procedures!
- As a professional, the knowledge and input that you can provide to your customers is even more important when things aren’t exactly “normal”.
Here’s a brief overview of some early season observations.
Black cutworm moths were captured in light traps, and seen at porch lights in Berks County this weekend. The black cutworm doesn’t usually overwinter here, but instead the adults are blown here from southern areas with weather fronts. Their arrival means that in about two weeks, you could start to see the feeding damage from the caterpillars, especially on bentgrass greens and tees.
The adult female moths can lay 1200-1600 eggs over a 5-10 day period! The eggs are usually attached to the tips of grass blades or other low, dense-growing plants. Larger cutworm larvae will make burrows or use aerator holes or other holes as their “home base”, and feed nightly around that hole. There can be three generations, so keep an eye out or use disclosing solution to help you find suspect caterpillars. Detailed fact sheet from Rutgers University
Black turf ataenius adults were seen flying in early April. These small (3/16 inch) black beetles overwinter as adults, and emerge when red buds are in bloom. In flight, they seem to float on the evening breeze and they are attracted to lights. Their movement from overwintering sites lasts over a month.
Egg laying starts when Vanhoutte spirea comes into full bloom (usually May to early June). The larvae feed on Kentucky bluegrass, annual bluegrass, and bentgrass, causing typical white grub damage. You’ll find them on golf courses and lawns. The grubs are tiny and often overlooked, but could begin to cause damage in early June especially if it’s dry.
Annual bluegrass weevil continues to plague golf turf throughout the northeast. Adults have been active for a number of weeks, and as their name implies, they feed mostly on annual bluegrass (although they will also eat closely mown perennial ryegrass or bentgrass). Adults overwintered in brushy or protected areas around greens and tees, and have moved back into the turf.
Like the related billbug, their larvae feed through the stem of annual bluegrass and eventually end up feeding on the crowns. One larva can injure as many as 20 stems. We can have three overlapping generations during the summer season.
Follow Dr. Pat Vittum’s timely posts about annual bluegrass weevil and other turfgrass pests.
What about billbugs? The bluegrass billbug is also a weevil that overwinters as an adult. Adults become active, walk around and find mates once the temperatures are over 60 degrees. More accurate predictions about their activity can be made by using the degree-day model developed by Dr. Dave Shetlar, from Ohio State University. Dr Shetlar found that first adult activity should occur between 280 and 352 DD50 (base 50, March 1 start date).
In Berks County, we are currently at 230 GDD and moving fast. Adults can be found walking on paved surfaces, or in the grass at the base of plants.
Billbugs in Home Lawns Fact Sheet, Dr. Paul Heller