Billbugs are out in full force in West Lafayette and I’m certain they have already started to deposit eggs into stems. Some of those eggs have probably started hatching which means the larvae are already actively feeding inside plant stems. For those who have been challenged by billbugs in the past, the time to apply chemical controls is NOW! At this time, we would lean toward the neonicotinyls (chlothianidin, dinotefuran, imidacloprid or thiamethoxam) or Acelepryn® (chlorantraniliprole) because the systemic activity of these compounds will provide control of larvae inside the stems. If you are also thinking ahead to white grub control later in the season, make sure to use the highest labeled rates or risk losing the benefits of residual grub control later in the season (expect white grub season to start earlier this year too).
This may be one of those years when we experience two full generations of billbugs even in the northern part of the State, so good control of the first generation will be extremely important. Our turf will be able to tolerate a fair amount of damage from the first generation since growing conditions will likely make recovery less challenging. However, a second generation with damage occurring in the hot dry months of July and August can be much more problematic ¾ just ask anyone who regularly deals with hunting billbugs in Southern Indiana and Kentucky.
Speaking of hunting billbug… experience would indicate that these insects have been out and about for some time now in Southern Indiana and it is very likely that most eggs have already hatched. As with the other billbug species, target the larvae inside the stems at this time using one of the previously mentioned insecticides.
Overwintered sod webworm larvae have also begun feeding and the birds have, no doubt, keyed in on this activity. If you are experiencing damage related to sod webworms or birds foraging for these insects on short-cut bentgrass, an application of any of the pyrethroids (bifenthrin, beta-cyfluthrin, deltamethrin, lambda-cyhalothrin etc…) should remediate the insect problem. If birds are actively foraging in these areas, try to avoid using granular materials and do not water-in liquid applications.Cutworms and Armyworms
As Dr. Gibb has pointed out, substantial numbers of adult black cutworms and armyworms are already present and laying eggs in the turf ¾ the larvae will not be far behind. Keep an eye out for indications of damage and treat accordingly. Remember that a tablespoon of lemon-scented dishwashing detergent in a gallon of water can provide an effective and simple sampling tool for these insects when poured over a square yard of turf. A few short minutes of observation after a soap flush can clarify if treatment is required.