We have noticed an increase in June beetle (June Bug) larvae or Grubs as many of you know them. European Chafers have been the primary focus as of the past 3 – 4 years and before then from our standpoint. However, the May – June Beetle has many different species. One of these species of beetle is called Phyllophaga. The problem with this grub is it typically has a 2 – 3-year life cycle. This means it stays a grub for up to 3 years. If you notice grub damage in your lawn during the summer months. Skunks or birds digging in your lawn, please call us. We are working with the Cooperative Extension in locating areas of infestation. Weather conditions and environmental changes are usually the main reasons why insect populations increase or decrease. Control for these insects is difficult in turfgrass. Our normal grub control will not have much effect on them if they are beyond the 1st year. This is why when customers have grubs, our technicians are digging them up to look to determine what species they are. Japanese Beetle and European Chafer have been the primary focus as of late. As mentioned before Phyllophaga (June Bug) grubs feed for up to 3 years or more in some cases. When that happens the size of them can reach up to the size of your pinkie finger!!! Eeeeww!!! Just imagine how much turfgrass root systems these guys need to eat each day! Hopefully, now you can see the cause for concern.
The Phyllophaga life cycles vary somewhat because some species complete their growth in one year, while others require as much as four years. The common life cycle of the more destructive and abundant of these beetles extends over three years. The adults mate in the evening and, at dawn, females return to the ground to deposit 15 to 20 eggs, 1 to 8 inches deep in the soil. Since the adults are attracted to trees to feed, they tend to lay most eggs in the higher portions of sod near wooded areas. Eggs hatch about three weeks later into young larvae that feed upon roots and decaying vegetation throughout the summer and, in the autumn, they migrate downward (to a depth of up to 1.5 meters) and remain inactive until the following spring. At this point in the insect’s life cycle, the greatest amount of damage occurs as the larvae return near the soil surface to feed on the roots of the plants. The next autumn, the larvae again migrate deep into the soil to overwinter, returning near the soil surface the following spring (the third spring) to feed on plant roots until they are fully grown in late spring. These grubs then form oval earthen cells and pupation follows. The adult beetles emerge from the pupal stage a few weeks later, but they do not leave the ground. The beetles overwinter, emerging the following year in May or June when feeding, mating, and egg-laying take place.
Here is a view of the Raster pattern on this species.