Hunting billbug is becoming a significant problem in parts of southern Indiana where zoysiagrass is grown. These insects typically have two generations per year in this part of the Midwest with the larvae of both generations being capable of causing significant injury to turf. Sporadic adult hunting billbug activity has already been observed in the Evansville area marking the beginning of egg laying by overwintered adults.
Applications of insecticides targeting these insects should already be in place or should be applied as soon as possible. If pyrethroid insecticides such as Talstar, Astro or Deltagard are used to target adults before significant egg laying occurs, optimal timing will typically be sometime on or before April 15.
Chloronicotinyls such as Merit, Meridian, and Arena, combination products such as Aloft and Allectus, and the anthranilic diamide Acelepryn can also be applied during this time frame. However, since these later compounds have the added bonus of systemic activity that will kill larvae inside the plant, applications made as late as the first of May should still be effective.
Unfortunately, experience has shown that spring applications of any of these compounds will not adequately control the second generation of this insect which can easily move into previously treated areas from surrounding untreated areas. Therefore, a second application in mid to late July may be necessary. When making this second application, be sure to not surpass allowable annual usage rates for any given product. The easiest way to avoid such a mistake is to use different products for spring and summer applications.
Figure 1. Adult hunting billbug
Figure 2. Hunting billbug larva in zoysiagrass (early July)